Thanks to all here for the learned advices offered.
Regarding a swap of a turbo Ecotec into a Fiero, I am looking at a transmission choice between F35 or an F40 options.
This will be a daily driver vehicle with an occasional heavy foot applied. No racing, etc so I don't anticipate beating the tranny up. The LHU and LTG engines (stock) produce up to 270 hp and up to 295 ft-lb torque, hence my focus on an F35 or F40. The F35 is rated to at least 260 lb-ft input torque. The F40 is rated to at least 295 lb-ft input torque. The Fiero being lighter than the vehicles these are usually found in, I'm sure these would be my optimal choices for an Ecotec/Fiero swap.
I've read much about required intermediate shaft and axles requirements. My problem at hand is which one would be the least difficulty / least expensive choice, with least expensive being my primary concern.
Which transmission would you advise I choose to use with a turbo Ecotec, an F35 or an F40, and why? What, exactly would one need to accomplish installation (flywheel, clutch, half shaft, axles)?
Thanks in advance for any help with this.
------------------ Steve Mushynsky
1984 Fiero 2M4 34K miles
1986 Fiero SE I4 (donor now) Lots of good miles. One very bad mile.
1987 Fiero Tried to kill me (gone to a 'better place') Prior owner failed to tighten a bolt. Trailing arm separated at 70 mph
[This message has been edited by SteveMushynsky (edited 11-16-2019).]
A lot of the ss/redline guys prefer the base model f23 to the sc/tc f35. F23 are dime a dozen and have been said to be stronger than the f35. Besides that information, I'm not too much help to ya. I would go with whatever has a better gear ratio for your planned application.
Originally posted by oldrock2401: A lot of the ss/redline guys prefer the base model f23 to the sc/tc f35. F23 are dime a dozen and have been said to be stronger than the f35. Besides that information, I'm not too much help to ya. I would go with whatever has a better gear ratio for your planned application.
Thanks for the reply, oldrock2401.
The F23 is rated by GM for at least 170 lb-ft torque. With the LHU and LTG producing up to 295 lb-ft torque, the F23 looks to me to be inviting eventual problems.
There are F35s available with limited slip differential and 4.05 final drive ratio for $500 and up, though their mileage is high. F40s with 3.76 final drive ratio can be had for $250 and up with half the mileage. Either can be had in Ecotec bellhousing versions.
So, my personal choice is F35 or F40. What's needed re half shaft, axles, etc and costs thereof is the question.
------------------ Steve Mushynsky
1984 Fiero 2M4 34K miles
1986 Fiero SE I4 (donor now) Lots of good miles. One very bad mile.
1987 Fiero Tried to kill me (gone to a 'better place') Prior owner failed to tighten a bolt. Trailing arm separated at 70 mph
Im aware the f35 is "rated" higher, hop on the ss forums and many switch to the f23 because its stronger, theres quite a few guys with 500+whp on them in both that community and the 3.8 community here. Just because paper says its better, doesn't mean it is. F35 has different axles than the f23. There's quite a bit of information on here that covers f23 stuff for our cars, which is why I brought it to light.
Originally posted by oldrock2401: I'm aware the f35 is "rated" higher, hop on the SS forums and many switch to the F23 because its stronger, There's quite a few guys with 500+ whp on them in both that community and the 3.8 community here. Just because paper says its better, doesn't mean it is. F35 has different axles than the f23. There's quite a bit of information on here that covers f23 stuff for our cars, which is why I brought it to light.
Your reply is why I posted my intentions: To learn and to steer me toward info sources I should become familiar with. I've done a lot of reading research on the F23 and other options here and elsewhere. I'm fully aware that reading and studying isn't the same as experience. Questions, though, on how the F23 has been able to amass such a reputation despite GM's engineering criteria. Having some engineering background myself, I do know that breaking/shearing strength is one thing, but wear resistance and reliable lifetime is another. Loyalty to a well-established and widely used technology is no doubt another factor (ie: the 3800 Buick V6 engine's very strong following).
The F23 popularly swapped into the Fiero came in earlier vehicles with non-Ecotec engines. It is a logical replacement for the earlier Getrag in many Fieros. The F25 and the F35 were used in vehicles with the supercharged and early turbocharged Ecotec engines. The F40 was used in later cars with the higher output LHU tubo'd Ecotec.
A 500 hp vehicle equipped with an F23 would appear illogical, unless longevity was not a priority. It would be for me, though. I would guess that a 500 hp Fiero would likely be built and used occasionally as a race car and not for multi-year, high mileage daily driver use, where wear and reliability are big factors.
As a general rule, I am inclined to use as-current technology as feasible and that I can afford and that is engineer-designed to accommodate the application I would use it with. Yes, I fully acknowledge that builders of what are or essentially are high-performance race cars can accomplish amazing results outside the normal performance envelope, but that's not me. There's too much the practical engineer in me.
So, I think I'll stay with my chosen options being an F35 or F40. What are the issues of installing either of these?
------------------ Steve Mushynsky
1984 Fiero 2M4 34K miles
1986 Fiero SE I4 (donor now) Lots of good miles. One very bad mile.
1987 Fiero Tried to kill me (gone to a 'better place') Prior owner failed to tighten a bolt. Trailing arm separated at 70 mph
You need the F35 from the lsj supercharged cobalt as. The later turbocharged f35 transmision’s axles will not fit Fiero hubs. The F23 takes Fiero axles making it much easier to source. The f40 also needs axles from the supercharged cobalt SS
------------------ 86 GT built 2.2 ecotec turbo rear SLA suspension QA1 coilovers on tube arms
Originally posted by wftb: You need the F35 from the lsj supercharged cobalt as. The later turbocharged f35 transmision’s axles will not fit Fiero hubs. The F23 takes Fiero axles making it much easier to source. The f40 also needs axles from the supercharged cobalt SS
Thanks for your reply, wftb. I had repeatedly read that the outer end of Cobalt axles will not fit the Fiero hubs, but unsure what year Cobalts equipped with what transmissions they were writing about.
Is it accurate that the axles from the earlier supercharged Ecotec Cobalts equipped with the F25 transmissions WILL work with an F35 transmission and mate with Fiero hubs, but that the axles that were used in the later F35-equipped, turbocharged Ecotec Cobalts will NOT fit Fiero hubs?
In other words, one can use an F35 transmission off a later year turbocharged Cobalt in a Fiero IF one replaces the later year turbo Cobalt axles with the earlier year supercharged Cobalt axles, correct?
Is it safe to assume that the later year Cobalt's transmission jackshaft can be used with the earlier Cobalt axles?
Will the resulting axles & jackshaft lengths be correct without modifications? Are the earlier axles strong enough?
If I can definitely resolve this, I will feel much better about the feasibility of this project for me.
I will be using the F35 as it is lighter and smaller than the F40. The final drive ratios are close to each other as is the span of ratios from lowest to highest gears. The input torque rating of the F35 is a bit lower than I would like for an LHU or a LTG engine, but I'm sure that its engineered safety margin and my not hugely heavy accelerator foot will make this not a problem for me. I don't think I would care for cramming the offset Ecotec + big F40 combination into the Fiero cradle.
Hopefully this will put my axles worries to bed. Now I can constructively worry about something else.
------------------ Steve Mushynsky
1984 Fiero 2M4 34K miles
1986 Fiero SE I4 (donor now) Lots of good miles. One very bad mile.
1987 Fiero Tried to kill me (gone to a 'better place') Prior owner failed to tighten a bolt. Trailing arm separated at 70 mph
4thfiero: "F23 M86: Will this tranny accept Fiero axles? Will the stock cobalt axles fit the Fiero hubs? Will one of those jack shafts (or half shafts) fit into the f23 and will a Fiero axle fit into the jack shaft? Same questions for the F35 and F40 trannys... I really wanna use the F23 tranny with the jack shaft and 2 drivers side Fiero axles...will that work? If not, what can i do to make it work...(like using Cobalt axles if they are compatible)" Also... Can I hook up a 5 speed Getrag shifter (inside the car) to a 6 speed F40???? Will that "transform" my 5 speed shifter into a 6 speed? I would LIKE to use the F35 or the f40 tranny with my 2.4 turbo set up. I just need to know about the shifter and the axles...Do I use cobalt axles? Of what year? Which jack shaft do I use as well... I need a parts list to make this work and have everything the length I need!"
fieroguru: "One of the primary reasons people pick the F23 is because stock Fiero axles are used with it. The F40 and F35 can both use the Cobalt SS (supercharged version, not the turbo version) axles and intermediate shaft when installed in a Fiero. The F35 would place the engine in the approximate stock location, the F40 would shift it 1" to the passenger side (which there might not be room for - like many of the V8's). For the F23 or F35, you can use any shifter you want as the reverse lockout is part of the transmission. On the F40, its not part of the transmission and the Fiero 4 speed shifter is needed since it has the reverse lockout built into it."
4thfiero: "So if I'm reading this correct... I can use the F40 with cobalt supercharged axles and jack shaft...but the 5 speed shifter won't work with the 6 speed, but the 4 speed shifter will! If I use the F35, again use cobalt axles and jack shaft...and can I use my 5 speed shifter just fine?"
fieroguru: "Correct. The engine placement of the F35 will be very similar to a stock Fiero, but the F40 will need it to be 1" further to the passenger side and some engines don't have the room on the passenger side for this shift (mostly the V8's). The F23 and F35 can use a Fiero thickness flywheel (about .82"), but the F40 needs one that is much thicker. 4 speed shifter when used with the F40 needs to be modified (expand the slots to allow the 4th shift gate and to relocate one of the cable brackets on it). Custom shift cable brackets will be needed on the transmission side for any of the 3 transmissions and the needed shifter cables depends on your cable bracket design. If you use 2 Getrag select cables, you will likely break the one used for shifting - It simply isn't large enough for aggressive shifting. Custom transmission mounts are also needed for any of the 3 transmissions."
4thfiero: "Does the 5 speed Getrag shifter need to be modified for the f35? And do you know what cables I would need?"
fieroguru: "If you want to run the F40 with 2 Getrag select cables, then yes, the 4 speed shifter must be modified. The modification involved opening up a slot and relocating a shift cable bracket (cutting/welding)."
------------------ Steve Mushynsky
1984 Fiero 2M4 34K miles
1986 Fiero SE I4 (donor now) Lots of good miles. One very bad mile.
1987 Fiero Tried to kill me (gone to a 'better place') Prior owner failed to tighten a bolt. Trailing arm separated at 70 mph
That thread is 5 years old. There is now a better cable combination for the F40 and you can now use a 5 speed shifter with it with a bolt on reverse lockout.
The current issue is most available parts for the F40 are for the G6 version. The ecotec version is different in bolt patterns for mounts, clutch line connector, and shifter assembly mounting flange.
The F35 isn't any better... I think it has been used in a Fiero 1 or 2 times, so there isn't a kit for it either.
Originally posted by fieroguru: That thread is 5 years old....
Thank you again, fieroguru. I was hoping for updated comments.
The F40 looked like more size, weight, capacity, complexity and expenses than I wanted for this project.
The F35, I hoped, was going to be less complex / less costly regarding the axles aspect. I am comfortable with the above info resolution of that.
I had seen the bolt-on reverse lockout item online and am holding that thought in reserve in case I need it. My swap car currently is equipped with the early '84 4-speed transmission and associated gear. My donor has a THM-125 automatic.
As to linkages, etc needed to install an F35, that's my next focus of research. I believe I've seen a build thread or two that were to use an F35, although I don't remember if they got that far. We also have a SAAB parts yard near me for stuff & inspiration. Any info or leads to same on this aspect of installing an F35 in a Fiero would be welcome.
I have time to figure this all out, as I have yet to strip my red 1986 Fiero SE I4 donor car after clearing my garage to store parts. That will be my primary concern for the rest of this year, as my darling spouse has once again threatened to have it dragged to our corner and decorate it with lights for Christmas.
When I have the poor thing stripped, I will be listing / have available a passel of parts for purchase.
------------------ Steve Mushynsky
1984 Fiero 2M4 34K miles
1986 Fiero SE I4 (donor now) Lots of good miles. One very bad mile.
1987 Fiero Tried to kill me (gone to a 'better place') Prior owner failed to tighten a bolt. Trailing arm separated at 70 mph
The F23 is rated by GM for at least 170 lb-ft torque. With the LHU and LTG producing up to 295 lb-ft torque, the F23 looks to me to be inviting eventual problems.
If that rating were gospel, the Fiero community would not have been able to run Muncies and Getrags with V8's for years. Yes, the failure rate is higher than with the original engines, but it's not like they blow up the first time you go to WOT. I've run my Getrag into the 12's with 300 RWHP Northstar. I broke a Fiero inner CV joint due to wheel hop from worn suspension bushings, but not the transmission.
The "rating" is just the biggest number for which GM has ever used the transmission. That's all it is. Don't get wrapped around the axle with regard to that.
The Fiero driveline's weak spots are: 1. Outer CV joints; 2. Inner CV joints; 3. Getrag right differential bearing boss.
The Getrag's weakness is the right side of the differential case. Some failures have split the case and pushed that boss out due to axial loading from the helix angle on the ring & pinion mesh. The F23 case is clearly and obviously reinforced far and away above what the Getrag's case is... and yet the "rating" is the same.
I'm sure someone can link the build thread, but there's a member here who's run an F23 to the drag strip near/above 500 HP with a turbo 3800.
Since I'm building a V6/3.63 F23, I can assemble the leftover parts into an Ecotec/3.94 transmission and sell you that.
Originally posted by Will: If that rating were gospel ... ... Yes, the failure rate is higher than with the original engines, but it's not like they blow up the first time you go to WOT ... ... The "rating" is just the biggest number for which GM has ever used the transmission.
Thank you for your comments, Will.
From an engineering point of view, GM's transmission ratings of "At least XXX ft-lbs torque" would be defined as the most anticipated, but not the maximum, load the unit is certified (warranted) to in its normally anticipated use environment, with a sizable safety margin included.
Ratings for a device like a transmission reflect constant-motion wear / reliability, sudden shock stress capacity, among other factors such as installation with a dual-mass or solid flywheel or electronic shifting-torque shock mediation measures.
This is why I said I felt confident that the F35, rated at somewhat less than the torque output of an Ecotec LHU / LTG, would be adequate for regular road use in a Fiero, which is 500-800 lbs lighter than the Cobalt the F40 was used in. Not so much so for the F23, despite anecdotes about its occasional use outside of its designed-for environment. My aim is to create a long-term reliable daily driver with 'guts'.
Please, no more advocacy replies from fans of the venerable F23. I'm past that decision point.
My questions are regarding installation of an F35 transmission into a pre-1988 cradle. Specifically at this point regarding how to accomplish shifting linkages in what is now a 1984 4-speed Fiero. Thanks.
------------------ Steve Mushynsky
1984 Fiero 2M4 34K miles
1986 Fiero SE I4 (donor now) Lots of good miles. One very bad mile.
1987 Fiero Tried to kill me (gone to a 'better place') Prior owner failed to tighten a bolt. Trailing arm separated at 70 mph
In that case I am pretty sure you want the F35 from a supercharged Cobalt SS. The turbocharged Cobalt SS as stated before has axles that have the wrong splines to fit Fiero hubs. In addition to that the axle shafts are a larger diameter so I am pretty sure that they will not fit the earlier jack shaft found on a supercharged Cobalt SS.
------------------ 86 GT built 2.2 ecotec turbo rear SLA suspension QA1 coilovers on tube arms
Also note that the LTG has a different bellhousing than the LHU (LOTS of other differences too). Only trans that will bolt right to an LTG is the F40 (from a Regal with the LTG).
(You mention the LHU/LTG torque. Not sure if you're actually considering an LTG or not...)
[This message has been edited by ennored (edited 11-20-2019).]
Originally posted by wftb: In that case I am pretty sure you want the F35 from a supercharged Cobalt SS. The turbocharged Cobalt SS as stated before has axles that have the wrong splines to fit Fiero hubs. In addition to that the axle shafts are a larger diameter, so I am pretty sure that they will not fit the earlier jack shaft found on a supercharged Cobalt SS.
Thanks again for your reply. I do value your inputs.
This reinforces what I understand to be the case.
------------------ Steve Mushynsky
1984 Fiero 2M4 34K miles
1986 Fiero SE I4 (donor now) Lots of good miles. One very bad mile.
1987 Fiero Tried to kill me (gone to a 'better place') Prior owner failed to tighten a bolt. Trailing arm separated at 70 mph
Originally posted by ennored: Also note that the LTG has a different bellhousing than the LHU (LOTS of other differences too). Only trans that will bolt right to an LTG is the F40 (from a Regal with the LTG). (You mention the LHU/LTG torque. Not sure if you're actually considering an LTG or not...)
Thank you, ennored.
Yes, I was considering the LTG as well as the LHU as they seem to get about the same price on the used engines markets. Not so many people are looking for the limited-use LHU while the LTG's price is depressed by there being so many of them about, I assume.
I understand that the LTG is an evolution of the Ecotec line with GM having said that there is almost nothing in common with previous Ecotech versions.
I see enough references online that the LTG has a different mounting pattern and different starter placement that the LTG is off my preference/selection list. Thanks much for pointing this out.
So, LHU it will be
------------------ Steve Mushynsky
1984 Fiero 2M4 34K miles
1986 Fiero SE I4 (donor now) Lots of good miles. One very bad mile.
1987 Fiero Tried to kill me (gone to a 'better place') Prior owner failed to tighten a bolt. Trailing arm separated at 70 mph
[This message has been edited by SteveMushynsky (edited 11-20-2019).]
I have a 2007 2.4 le5 ecotec Turbo, in a 1988 Fiero GT with around 400 wheel HP. I use the F23 tranny with a Quaife LSD installed. I wa slooking into the f35 vs the f23 and the f23 won for me. The f23 are WAY cheaper and easier to find, and they were built stronger it seems. The f35's had a lot of issues and didnt seem to hold power as much as they claimed. ZZP performance also has custom flywheels that fit on the f23 to install f35 clutches as well to hold more hp. Myself and other ecotec uses (custom cobalts) with 600 plus hp use the F23 tranny bcc we prefer the gear ratio, reliability and price of the tranny. The swap is also easy.
I have been driving with this tranny for years now and ive never had an issue with it. Its a solid tranny.
Originally posted by SteveMushynsky: Please, no more advocacy replies from fans of the venerable F23. I'm past that decision point.
quote
Well... you certainly won't be the first person to do something the hard way when there's an easier way right next to it.
Thanks, Will. I have witnessed your advocacy on this on various other threads as well. Your loyalty to the F23 is admirable. I actually do value your input. Snarkiness not really required, though. (No offense taken)
I see on SAAB forums concern about F23's and questions about transferring "stronger" F35 internals into their cases for use in their vehicles. I've also seen posts stating that choice of transmission fluid used is paramount re performance and reliability and also absolute warnings not to use additives in same. There seems to more involved in the overall F23 vs F35 reputation dispute than justifies a simple single, emphatic answer.
I won't be thrashing this transmission all that much, actually. I'm in this to learn, not to leave flaming tracks on the road. Let's see how this works out, shall we?
------------------ Steve Mushynsky
1984 Fiero 2M4 34K miles
1986 Fiero SE I4 (donor now) Lots of good miles. One very bad mile.
1987 Fiero Tried to kill me (gone to a 'better place') Prior owner failed to tighten a bolt. Trailing arm separated at 70 mph
Originally posted by 4thfiero: ... I use the F23 tranny with a Quaife LSD installed. I was looking into the f35 vs the f23 and the f23 won for me ... I have been driving with this tranny for years now and I've never had an issue with it. It's a solid tranny.
Thank you for relating your choice and experience. Duly noted.
------------------ Steve Mushynsky
1984 Fiero 2M4 34K miles
1986 Fiero SE I4 (donor now) Lots of good miles. One very bad mile.
1987 Fiero Tried to kill me (gone to a 'better place') Prior owner failed to tighten a bolt. Trailing arm separated at 70 mph
F23: -Can buy mount brackets -Can buy shift linkage -Clutch similar to stock -Uses stock Fiero stickshift axles -Strong enough for your needs
F35: -Must make brackets from scratch -Must make shift linkage from scratch -Specialized clutch -Must make hybrid axles -Do all that and still have only 5 gears
Heck, one of the engines you're thinking about ships from the factory with the F40 bolted to it. The F40 is probably an easier swap than the F35 because brackets and shift linkage for it are available for purchase and most of the rest of the work is the same. Just buy the whole package.
[This message has been edited by Will (edited 11-21-2019).]
Originally posted by Will: F23: -Can buy mount brackets -Can buy shift linkage -Clutch similar to stock -Uses stock Fiero stickshift axles -Strong enough for your needs F35: -Must make brackets from scratch -Must make shift linkage from scratch -Specialized clutch -Must make hybrid axles -Do all that and still have only 5 gears Heck, one of the engines you're thinking about ships from the factory with the F40 bolted to it. The F40 is probably an easier swap than the F35 because brackets and shift linkage for it are available for purchase and most of the rest of the work is the same. Just buy the whole package.
Will, I am aware of your long evangelical history of advocacy for the F23. And you are aware of my prior responses as well. To reiterate:
F35 axles from the supercharged Cobalt SS series fit the F35-Fiero application. They fit the Fiero hubs. They are 1/2" shorter, but that is no hindrance. The F40, by the way, would require at least one axle to be custom-made.
Clutches of various capacities are easily available for the F35, from cheap stock to all out racing designs.
F35's, by the way, can be had new at very low cost. I have one on the way to me now. If I can secure a source of factory units, I might offer them cheap online sometime.
As I said earlier, "strength" of a device like a mechanical transmission is defined from an engineering point of view as resistance to sudden, jarring change of torque load & shock and resistance to wear and failure over long-term use. The numerical portion of these transmissions' identifiers refers to the "at least" stated maximum steady load that the manufacturer will warrant. "23" stands for "230 newton-meters "or 170 lb-ft of torque; "35" stands for "350 newton-meters"or 258 lb-ft of torque; "40" stands for "400 newton-meters" or 295 lb-ft of torque. No doubt, each of these figures has a sizable unspoken safety margin built in, but one gets the idea.
Also, what car a transmission is installed into and how and for what it is driven has to be a huge factor, too. The supercharged and turbo'd Cobalts were notorious for experiencing "wheel hop", exacerbated no doubt, by the demographic of drivers involved. True race cars also are not driven with primary concern for transmission or engine longevity, although they get better care and maintenance.
I won't be circuit racing or drag racing my completed car. As I've already said here, my aim is to create a road car with impressive "oomph" - and to do a parallel project to my son's engine-transplanted MR2 (He's a Toyota Certified Master Mechanic). He's got WAY more knowledge than I, but I can learn and I have lots of time to do so.
The truth is that all engines found in popular, powerful cars today have torque far in excess of their transmissions' rated capacities. Modern transmissions like the F40 reduce sudden torque shocks with dual-mass flywheels. Modern ECU's and TCM's compensate by reducing torque produced from standing starts and during gear shifts.
I look forward to learning what I need to construct appropriate engine and transmission mounts at right angle axes to hopefully provide maximum stability. If I succeed, I imagine others would like to know how. Perhaps I might even be able to provide F35 mounts to others, even. What's wrong with that?
As to gear ratios, the span from low to high gear ratios is almost identical for the F35 and the F40. Would I miss one extra gear in a car with close to 300 hp and close to 300 lb-ft, stock on the road? I really doubt that. 6th gear conversions for F35's can be found also, if one looks hard enough and really has the need to more often shift a high-torque engine with a flat performance curve that badly.
Will, you've proselytized for F23's on this thread before. I do value your input but as I've said, I am past that and have made my choices for engine (LHU) and transmission (F35). Please let that lie here. I've explained and made my choice. I look forward to hearing any helpful advice within this scenario. Shall we see how it eventually works out for me?
------------------ Steve Mushynsky
1984 Fiero 2M4 34K miles
1986 Fiero SE I4 (donor now) Lots of good miles. One very bad mile.
1987 Fiero Tried to kill me (gone to a 'better place') Prior owner failed to tighten a bolt. Trailing arm separated at 70 mph
[This message has been edited by SteveMushynsky (edited 12-07-2019).]
If you want to put power to a F35, there are 2 primary upgrades you will want to do (convert to shims vs. crush sleeve on the main shaft) and rework the bolt method for the main shaft bearing retainer/differential support strap.
Originally posted by wftb: When you get you F35, post some pictures of it. I would be interested to see what external difference there is compared to my F23. Are you getting the F35 with the LSD ? That was an option for the supercharged Cobalt SS.
I will do that as I can. I have been unwell for the last several weeks and unable to get out & about at will. "If the creek don't rise", I'll be able to post pics soon. I am also interested in commonality of mount arrangements between the F23 and the F35 as both saw service in the same car (Cobalt). I believe I've seen that some mounts themselves are the same. Don't know if placement is the same.
As to LSD, leftover new F35s with LSD are rare and quite expensive. I had a choice of a factory overstock new unit with zero miles and no LSD or a used one with LSD at about the same cost with shipping that had LOTS of miles on it. Since this is going to be a seasonal daily driver (and I have doubts about the quality of those miles with some Cobalt SS drivers), I opted for the new unit without LSD. It looks like LSD add-ons are available new or used, though I haven't researched costs much.
My total cost, including shipping, for a factory overstock new F35 w/o LSD was $628. I'm working on the possibility of getting these for quite a bit less, should anyone else want one.
This is going to be an interesting, though long-term, project. My health is going to be a factor as I had a ten-year autoimmune inflammation situation (think PAIN), pretty much beat that, then got zonked with heart failure a couple years ago. It's controlled, but some months are better than others.
So, next question is re welding equipment. I'll start a separate thread on that.
------------------ Steve Mushynsky
1984 Fiero 2M4 34K miles
1986 Fiero SE I4 (donor now) Lots of good miles. One very bad mile.
1987 Fiero Tried to kill me (gone to a 'better place') Prior owner failed to tighten a bolt. Trailing arm separated at 70 mph
[This message has been edited by SteveMushynsky (edited 12-08-2019).]
Originally posted by fieroguru: If you want to put power to a F35, there are 2 primary upgrades you will want to do (convert to shims vs. crush sleeve on the main shaft) and rework the bolt method for the main shaft bearing retainer/differential support strap. https://www.genuinesaab.com/psi/gearbox.htm
Thanks much for the tip, fieroguru. I will definitely look into that.
I have read that some of the "F35" units used in some of the SAABs (until the last years) were actually weaker F25's with F35 differentials. Full upgrade came not long before the Cobalt SS S/C years. I'll be interested to see if this was part of any strength issues.
------------------ Steve Mushynsky
1984 Fiero 2M4 34K miles
1986 Fiero SE I4 (donor now) Lots of good miles. One very bad mile.
1987 Fiero Tried to kill me (gone to a 'better place') Prior owner failed to tighten a bolt. Trailing arm separated at 70 mph
The front engine Ecotec turbo guys have little problem with their transmissions (Aisin AR5), which IIRC GM rates for 260 Tq, but hold up to at least 400 Tq if not abused - GM themselves issued the GMPP tune which bumped torque from 260 to 340 Tq.
The Cobalt guys do seem to have some trouble with their transaxles but I don't know if it is inherent or due to those guys being a generally pretty rowdy bunch more likely to abuse the hardware. If you want to drive sensibly in your Fiero, I'd say that you should be OK.
Originally posted by BillS: Just noticed this thread, Steve. The front engine Ecotec turbo guys have little problem with their transmissions (Aisin AR5), which IIRC GM rates for 260 Tq, but hold up to at least 400 Tq if not abused - GM themselves issued the GMPP tune which bumped torque from 260 to 340 Tq. The Cobalt guys do seem to have some trouble with their transaxles but I don't know if it is inherent or due to those guys being a generally pretty rowdy bunch more likely to abuse the hardware. If you want to drive sensibly in your Fiero, I'd say that you should be OK.
I rather thought so, but brand loyalty is strong among people.
The Cobalts appear to have been noted for transmission-destroying wheel hop.
------------------ Steve Mushynsky
1984 Fiero 2M4 34K miles
1986 Fiero SE I4 (donor now) Lots of good miles. One very bad mile.
1987 Fiero Tried to kill me (gone to a 'better place') Prior owner failed to tighten a bolt. Trailing arm separated at 70 mph
It appears that some of the questionable things I may have done in my life (I'm not admitting to anything) have come back to bite me in my butt.
The F35 NOS transmission purchase I made at eBay turns out to have been a fraud. Contact with/from seller abruptly cut off and no transmission delivered or trackably en route. Oh well, that's what the eBay guarantee and the St Louis police are for.
I'll get my money back in full and hopefully, he'll get his. The search is renewed.
------------------ Steve Mushynsky
1984 Fiero 2M4 34K miles
1986 Fiero SE I4 (donor now) Lots of good miles. One very bad mile.
1987 Fiero Tried to kill me (gone to a 'better place') Prior owner failed to tighten a bolt. Trailing arm separated at 70 mph
[This message has been edited by SteveMushynsky (edited 12-30-2019).]
Originally posted by SteveMushynsky: It appears that some of the questionable things I may have done in my life (I'm not admitting to anything) have come back to bite me in my butt. The F35 NOS transmission purchase I made at eBay turns out to have been a fraud. Contact with/from seller abruptly cut off and no transmission delivered or trackably en route. Oh well, that's what the eBay guarantee and the St Louis police are for. I'll get my money back in full and hopefully, he'll get his. The search is renewed.
Promptly refunded in full by eBay. On to plan B.
[This message has been edited by SteveMushynsky (edited 12-30-2019).]
