Clutch problem update: I am hoping the brain trust can decipher the new twist to this problem, so here it is. I separated the engine from the transmission. As I turn the input shaft of the F40 , the axles turn as expected. Changing to different gears resulted in the axles turning at different speeds as expected, but if someone holds the axles still, the input shaft can still be turned. I thought that the shafts were supposed to be geared together. What I thought was a clutch always disengaged was really a transmission problem. What am I missing here? What should I be looking for?
If both axles are held still, you should not be able to turn the input shaft. If just one axle is held still, the input shaft should be able to turn the other axle. If you hold the input shaft still, and turn one axle, the other axle should turn in the opposite direction. Unless you have a POSI unit (LSD) - which would be quite uncommon, and spendy - you have an "open" differential.
[This message has been edited by Raydar (edited 10-03-2020).]
If both axles are held still, you should not be able to turn the input shaft. If just one axle is held still, the input shaft should be able to turn the other axle. If you hold the input shaft still, and turn one axle, the other axle should turn in the opposite direction. Unless you have a POSI unit (LSD) - which would be quite uncommon, and spendy - you have an "open" differential.
Yup, that's how it should work, but it isn't. I'm wondering what can break or be assembled wrong to give the results I'm seeing. I picked up this transmission at a wreaking yard in Riverside, California in 2016. They said it came from a running car.
I can speak in generalities, but I don't know anything about the internals of an F40. Over my head. Perhaps Joseph can chime in.
Edit - Are you sure it's all the way in gear? I've seen other trannies that had enough drag to move stuff in neutral that shouldn't be turning. Of course if you reached out and grabbed it, it would stop. Sorry. Don't mean to sound condescending. Just can't imagine anything that would break, and cause the symptoms you are describing. Clutching at straws, here.
[This message has been edited by Raydar (edited 10-03-2020).]
I can speak in generalities, but I don't know anything about the internals of an F40. Over my head. Perhaps Joseph can chime in.
Edit - Are you sure it's all the way in gear? I've seen other trannies that had enough drag to move stuff in neutral that shouldn't be turning. Of course if you reached out and grabbed it, it would stop. Sorry. Don't mean to sound condescending. Just can't imagine anything that would break, and cause the symptoms you are describing. Clutching at straws, here.
Probably the greatest issue that put these transmissions on the market brand new (first GM generation) and steeply discounted, is the fact that there were many complaints about shifting them into gear when cold, particularly while the engine was running. Sometimes it was necessary to shut the engine off and put the transmission in first and then start the engine up, until the transmission warmed up (which I had to do a few times). My first F40 was from a salvaged vehicle and it eventually failed behind considerably more torque than what it was designed to handle in about a year. The second transmission was new from bmwguru (thanks for that man), still first design, held up to the same motor over 5 yrs, although with considerably less off the line torque than it had initially (but still too much) and to my knowledge did not fail after the car was sold over 3 yrs ago.
Without a history to assess, there's no telling what condition the transmission was in when purchased. It could have been in trouble in the car it came from, especially if the owner had trouble shifting it and applied excessive force to the shifter to make it go into gear. Slam those levers with force by hand into position and make sure you have it in gear, or the appearance of "Has to be in gear" and see if the condition changes. If it doesn't, the transmission is broken. It could have been damaged on impact if the donor was wrecked.
[This message has been edited by Joseph Upson (edited 10-03-2020).]
Check to make sure all gears have axle rotation while rotating the input shaft. If it is only 1 gear doesn't have rotation, a single gear could be stripped. If you lost half the gears, one of the two main shaft pinion gears could have stripped. If all the gears are gone, then if could be the ring gear or the spider gears stripped. Any of these failure modes would leave lots of metal bits in the transmission, so drain the transmission oil and check for metal chunks.
The F40 is super easy to disassemble. Put the shifter in neutral, removed the flange bolts and pull it out. Remove the case half bolts from the bellhousing area (these are easy to miss) as well as the ones from the passenger side of the differential housing. Set the transmission on the bellhousing face. Remove all the rest of the bolts, and gently pry open the case. Carefully lift the gear side case off and you will be left with all the shafts and gears exposed like this:
From there, you can remove the shift forks/shafts, as well as the gear stacks (just wiggle them side to side so the interlocking gears have room to pass by each other).
[This message has been edited by fieroguru (edited 10-03-2020).]
Check to make sure all gears have axle rotation while rotating the input shaft. If it is only 1 gear doesn't have rotation, a single gear could be stripped. If you lost half the gears, one of the two main shaft pinion gears could have stripped. If all the gears are gone, then if could be the ring gear or the spider gears stripped. Any of these failure modes would leave lots of metal bits in the transmission, so drain the transmission oil and check for metal chunks.
The F40 is super easy to disassemble. Put the shifter in neutral, removed the flange bolts and pull it out. Remove the case half bolts from the bellhousing area (these are easy to miss) as well as the ones from the passenger side of the differential housing. Set the transmission on the bellhousing face. Remove all the rest of the bolts, and gently pry open the case. Carefully lift the gear side case off and you will be left with all the shafts and gears exposed like this:
From there, you can remove the shift forks/shafts, as well as the gear stacks (just wiggle them side to side so the interlocking gears have room to pass by each other).
Probably the greatest issue that put these transmissions on the market brand new (first GM generation) and steeply discounted, is the fact that there were many complaints about shifting them into gear when cold, particularly while the engine was running. Sometimes it was necessary to shut the engine off and put the transmission in first and then start the engine up, until the transmission warmed up (which I had to do a few times). My first F40 was from a salvaged vehicle and it eventually failed behind considerably more torque than what it was designed to handle in about a year. The second transmission was new from bmwguru (thanks for that man), still first design, held up to the same motor over 5 yrs, although with considerably less off the line torque than it had initially (but still too much) and to my knowledge did not fail after the car was sold over 3 yrs ago.
Without a history to assess, there's no telling what condition the transmission was in when purchased. It could have been in trouble in the car it came from, especially if the owner had trouble shifting it and applied excessive force to the shifter to make it go into gear. Slam those levers with force by hand into position and make sure you have it in gear, or the appearance of "Has to be in gear" and see if the condition changes. If it doesn't, the transmission is broken. It could have been damaged on impact if the donor was wrecked.
Yes, used stuff is iffy at best. It doesn't help that I have little experience with manual transmissions. I just am at a loss as to what would cause this sort of issue.
At the risk of appearing foolish, I have to fess up. I made many mistakes that led up to this issue. These are the big ones. 1. Leaks in the hydrolic line. 2. The left axle was not incerted all the way into the diff. It looks like the transmission is fine. I just need to be more careful with my mechanic work.
At the risk of appearing foolish, I have to fess up. I made many mistakes that led up to this issue. These are the big ones. 1. Leaks in the hydrolic line. 2. The left axle was not incerted all the way into the diff. It looks like the transmission is fine. I just need to be more careful with my mechanic work.
It takes a lot of character to come back and admit a mistake like that after all of the unnecessary labor that has resulted from it. It's also encouragement I believe for those of us trying to help to be more critical and insist that one check those little details that we tend to assume are too simple to miss and forgo mentioning them.
At the risk of appearing foolish, I have to fess up. I made many mistakes that led up to this issue. These are the big ones. 1. Leaks in the hydrolic line. 2. The left axle was not incerted all the way into the diff. It looks like the transmission is fine. I just need to be more careful with my mechanic work.
Ya' know... Zhit happens. You are also not the first Fiero person to make those identical mistakes. Probably not even this year.
Thanks for the encouragement. When I started this project, I think I mentioned that I hadn't done much mechanic work since I was in my early 20s. That was 40 years ago. A lot has changed about cars since then. I am learning, but not without a bunch of trial and error. Retirement is not as easy as it looks.
If it makes you feel even better, I put my first Fiero clutch disc on backwards, not realizing it was possible and not bothering to check, upon looking at the disc before install and seeing it was offset different on both sides. The symptom was failure to fully disengage and difficulty shifting into first, like in the F40 at times, until the springs wore down enough to clear the flywheel bolts. The clutch lining came apart after about 200 miles of driving, or less.
If it makes you feel even better, I put my first Fiero clutch disc on backwards, not realizing it was possible and not bothering to check, upon looking at the disc before install and seeing it was offset different on both sides. The symptom was failure to fully disengage and difficulty shifting into first, like in the F40 at times, until the springs wore down enough to clear the flywheel bolts. The clutch lining came apart after about 200 miles of driving, or less.
Oh no!, I guess I have a 50/50 chance. What way does the offset go?
Oh no!, I guess I have a 50/50 chance. What way does the offset go?
It should be stamped, or labeled on the clutch disc, but from the situation I had with the stock clutch, the highest offset side goes toward the pressure plate, which moves the dampening springs away from the flywheel bolts.
If you don't recall specifying that detail during assembly, it's cause for concern, as even if the springs do not interfere with the flywheel bolts, the reverse direction of rotation as it relates to contact shearing forces may still cause the lining adherence to fail, as was the case for me.
[This message has been edited by Joseph Upson (edited 10-05-2020).]
It should be stamped, or labeled on the clutch disc, but from the situation I had with the stock clutch, the highest offset side goes toward the pressure plate, which moves the dampening springs away from the flywheel bolts.
If you don't recall specifying that detail during assembly, it's cause for concern, as even if the springs do not interfere with the flywheel bolts, the reverse direction of rotation as it relates to contact shearing forces may still cause the lining adherence to fail, as was the case for me.
Looks like I got lucky. I guessed that would be the logical way it goes. Good to know there are so many knowledgeable people willing to give advice. Thanks again to all that give input.
Daryl, question for you; How do your axles look installed? I used the cobalt axles. I mounted up the suspension to get the car on the ground and while the drivers side looks good, the passenger side seems a little stretched. If I don't have the strut on, at max drop (not possible in running condition) you can feel the axle bearing start to leave the cup. While its fully in the cup on max drop with the strut installed, the boot seems a little stretched. Just wondering if you ran into this. I think I may need to move everything to the passenger side by a half inch.
Daryl, question for you; How do your axles look installed? I used the cobalt axles. I mounted up the suspension to get the car on the ground and while the drivers side looks good, the passenger side seems a little stretched. If I don't have the strut on, at max drop (not possible in running condition) you can feel the axle bearing start to leave the cup. While its fully in the cup on max drop with the strut installed, the boot seems a little stretched. Just wondering if you ran into this. I think I may need to move everything to the passenger side by a half inch.
Centering the assembly to help accommodate optimum axle arrangement is part of the deal unless you have custom axles made, although keeping the driver side axle as long as possible, which favors repositioning the assembly is probably better to avoid axle/joint separation when lifted. It has been several years since I swapped the F40, so I don't recall which side, but the axle seal to axle seal width is 1" wider to one side on the F40, compared to the stock options. I recall the Cobalt axles being equal length, so the difference will need to be adjusted for.
Centering the assembly to help accommodate optimum axle arrangement is part of the deal unless you have custom axles made, although keeping the driver side axle as long as possible, which favors repositioning the assembly is probably better to avoid axle/joint separation when lifted. It has been several years since I swapped the F40, so I don't recall which side, but the axle seal to axle seal width is 1" wider to one side on the F40, compared to the stock options. I recall the Cobalt axles being equal length, so the difference will need to be adjusted for.
Thanks,
I think at this point I'm going with custom axles. Couple issues; 1.) These cobalt axles look thin/weak, especially compared to the ones that came out of the saab. Since I plan on going boost after I put some miles on the swap, its nearly going to be a must 2.) The outer cups dont allow for the seal on the back of the upright. 3.) Lengths aren't ideal. I only have about an inch before the cam phaser connector starts hitting the strut tower. Half inch is all I would be comfortable with and honestly, I don't think that would be enough. 4.)I already (stupidly) pretty much completely welded the engine mounts to the subframe. Would require lots of work to cut them off and re-install.
Anyone have a good company to work with to get this done?
I think at this point I'm going with custom axles. Couple issues; 1.) These cobalt axles look thin/weak, especially compared to the ones that came out of the saab. Since I plan on going boost after I put some miles on the swap, its nearly going to be a must 2.) The outer cups dont allow for the seal on the back of the upright. 3.) Lengths aren't ideal. I only have about an inch before the cam phaser connector starts hitting the strut tower. Half inch is all I would be comfortable with and honestly, I don't think that would be enough. 4.)I already (stupidly) pretty much completely welded the engine mounts to the subframe. Would require lots of work to cut them off and re-install.
Anyone have a good company to work with to get this done?
Thanks,
It will be a while before I get everything assembled again, but I may be in a similar situation. If you find a good place to have axles made, let me know.
I think at this point I'm going with custom axles. Couple issues; 1.) These cobalt axles look thin/weak, especially compared to the ones that came out of the saab. Since I plan on going boost after I put some miles on the swap, its nearly going to be a must 2.) The outer cups dont allow for the seal on the back of the upright. 3.) Lengths aren't ideal. I only have about an inch before the cam phaser connector starts hitting the strut tower. Half inch is all I would be comfortable with and honestly, I don't think that would be enough. 4.)I already (stupidly) pretty much completely welded the engine mounts to the subframe. Would require lots of work to cut them off and re-install.
Anyone have a good company to work with to get this done?
Thanks,
If possible and practical, it might not be a bad idea to take on a surgical attitude along with a 2 lb hammer and see if you can create a tasteful relief in the strut tower, if not cut and weld one in for a little more clearance. I've just been reminded that you're working with the 3.6L and have different clearance limitations than what I faced.
Axles. Now that you've brought it up, the Cobalt SC axles are weak and have had a tendency to break near the outboard joint, which you have probably realized is tapered in that area for some limiting reason. The Turbo SS axles if I recall correctly, have splined shaft ends like those of the Saab which are not even close. The additional pwr of the 3.6L coupled with better traction potential than the fwd Cobalt will likely tax the axles a bit more, so your concern is not without merit.
The best option for a possible hybrid axle and a long shot given the age since they were made, would be to find the shortest axle shaft from the driver side of one of the old 440T transaxles, which I believe has the 32 spline count necessary (Don't waste your time at the major parts stores, they're likely all made in China now as I discovered when trying to replace my broken G6 axle and they are not interchangeable with GM parts.
Mate that to CV joints from the MANUAL Fiero transmission axles, as I found that the automatics had weaker joints with smaller internal parts/splines. I used axles from the Pontiac G6 GTP. The out board joint cups could be swapped with the Fiero cups. I used the full length passenger side, and sent the driver side off to Moser racing to have it shortened and resplined to work on the driver side.
They can make a pair of custom length shafts for your application. You'll just need to send them a shaft and a hub from either end. If they can't cut the simple snap ring groove in the axle by now, tell them not to bother. They put the typical rwd groove in mine and I put the snap ring in without thinking about it and put the joint on. Since the groove was too deep, the snap ring went eccentric and the joint was permanently locked on to the axle, which wasn't a problem since I figured I would never need to disassemble it, until I did when I managed to break the threaded end of the joint with the nut that keeps the bearing assembly together.
I did get the joint off to avoid having to have another shaft modified, but it involved a plasma cutter.
If possible and practical, it might not be a bad idea to take on a surgical attitude along with a 2 lb hammer and see if you can create a tasteful relief in the strut tower, if not cut and weld one in for a little more clearance. I've just been reminded that you're working with the 3.6L and have different clearance limitations than what I faced.
Axles. Now that you've brought it up, the Cobalt SC axles are weak and have had a tendency to break near the outboard joint, which you have probably realized is tapered in that area for some limiting reason. The Turbo SS axles if I recall correctly, have splined shaft ends like those of the Saab which are not even close. The additional pwr of the 3.6L coupled with better traction potential than the fwd Cobalt will likely tax the axles a bit more, so your concern is not without merit.
The best option for a possible hybrid axle and a long shot given the age since they were made, would be to find the shortest axle shaft from the driver side of one of the old 440T transaxles, which I believe has the 32 spline count necessary (Don't waste your time at the major parts stores, they're likely all made in China now as I discovered when trying to replace my broken G6 axle and they are not interchangeable with GM parts.
Mate that to CV joints from the MANUAL Fiero transmission axles, as I found that the automatics had weaker joints with smaller internal parts/splines. I used axles from the Pontiac G6 GTP. The out board joint cups could be swapped with the Fiero cups. I used the full length passenger side, and sent the driver side off to Moser racing to have it shortened and resplined to work on the driver side.
They can make a pair of custom length shafts for your application. You'll just need to send them a shaft and a hub from either end. If they can't cut the simple snap ring groove in the axle by now, tell them not to bother. They put the typical rwd groove in mine and I put the snap ring in without thinking about it and put the joint on. Since the groove was too deep, the snap ring went eccentric and the joint was permanently locked on to the axle, which wasn't a problem since I figured I would never need to disassemble it, until I did when I managed to break the threaded end of the joint with the nut that keeps the bearing assembly together.
I did get the joint off to avoid having to have another shaft modified, but it involved a plasma cutter.
Spoke to a company in Canada who is going to make some custom axles. Im trying to see if any upgrades can be done to the outer bearings to accommodate a larger spline but as of now, run the saab inners (which seem beefy) and the fiero outer at custom lengths is about $500.
I'd check with Moser and Strange first. I believe Moser still runs about $300 a pair for axle shafts. The cross the border deal would make me nervous, especially if your quote range is not anticipating any potential surprises at the border. Unless you're dealing with some pretty intense torque loads, the Fiero outboard joints will be fine, I'd focus on joining the different joints together.
Originally posted by Joseph Upson: The cross the border deal would make me nervous, especially if your quote range is not anticipating any potential surprises at the border.
Some three quarters of my Fiero parts purchases are cross-border... it's really nothing complicated.
At worst, anticipate 2 weeks of extra delay, and $200 of extra fees.
I'd check with Moser and Strange first. I believe Moser still runs about $300 a pair for axle shafts. The cross the border deal would make me nervous, especially if your quote range is not anticipating any potential surprises at the border. Unless you're dealing with some pretty intense torque loads, the Fiero outboard joints will be fine, I'd focus on joining the different joints together.
The Fiero outers are the first weak links in the driveline. There are 27 and 33 spline outers that readily replace the Fiero outers.
The Fiero outers are the first weak links in the driveline. There are 27 and 33 spline outers that readily replace the Fiero outers.
I'm speaking of the shaft itself, which is the same spline count as that of the G6, with the same outboard joint internals except the hub I believe which may be the spline confusion for me. I'm recollecting the axle shaft being 32, if it's 33 okay, I fiddled with several so getting them mixed up comes easy.
I did specify the manual trans shafts as being the stronger of the two earlier, and I just don't recall any instances here that would make the stronger of the two joints weak points for the naturally aspirated 3.6L and the Ecotec SC given how well they appear to have held up behind various other 300 hp range swaps and for me.
My joint failure was the result of an axle nut backing off and a subsequent break in the threaded portion of the joint. I also broke a bearing cage in the opposite axle, which I attributed to too much engine torque for the lowered ride height and axle angle at the joint. I don't remember if it was before, or after the transmission was taken out for the same reason, but know they were in close proximity to each other. If there's stronger stuff out there, by all means stick it on.
[This message has been edited by Joseph Upson (edited 10-15-2020).]
Originally posted by pmbrunelle: ... At worst, anticipate 2 weeks of extra delay, and $200 of extra fees.
I'll have to ask my wife about the possibility she may have a long lost sibling. That's definitely in line with her thinking; Saving money by using coupons before they expire, as opposed to just putting money in the bank.
All of the V6 lines should be the same, from year to year. 4 cylinder? I would expect the 87 and 88 lines to be different from the earlier years, since the 87 and 88 got a different compressor from the earlier years. I would expect 84s to be different from everything.
All of the V6 lines should be the same, from year to year. 4 cylinder? I would expect the 87 and 88 lines to be different from the earlier years, since the 87 and 88 got a different compressor from the earlier years. I would expect 84s to be different from everything.
All of the V6 lines should be the same, from year to year. 4 cylinder? I would expect the 87 and 88 lines to be different from the earlier years, since the 87 and 88 got a different compressor from the earlier years. I would expect 84s to be different from everything.
In the engine bay, yes, things will be different. I don't know about the '84, but everything else uses the junction block bolted to the left frame rail... so just make up lines that work how you need them to work and route how you need them to route between the junction block and the compressor.
I moved the junction block under the car to free up space.
It will be a while before I get everything assembled again, but I may be in a similar situation. If you find a good place to have axles made, let me know.
I got the car on the ground. No way stock cobalt axle will work, at least on the passenger side. Its actually pulling the whole driveline to the side, bearings are pulled out of the cup. I found a place that will make me some custom axles for ~$1k. Thanks for the user who informed me about the shipping customs fees associated with utilizing a Canadian company.
I got the car on the ground. No way stock cobalt axle will work, at least on the passenger side. Its actually pulling the whole driveline to the side, bearings are pulled out of the cup. I found a place that will make me some custom axles for ~$1k. Thanks for the user who informed me about the shipping customs fees associated with utilizing a Canadian company.
I'm not sure what I am looking at in your photo, but I would be interested in knowing how much longer your custom axles will be that the Consult axles.
I got the car on the ground. No way stock cobalt axle will work, at least on the passenger side. Its actually pulling the whole driveline to the side, bearings are pulled out of the cup. I found a place that will make me some custom axles for ~$1k. Thanks for the user who informed me about the shipping customs fees associated with utilizing a Canadian company.
That's looking down at the PS shock tower.
Whoa!
I'm using the cobalt turbo axles resplined for a G6 cage/tripot with fiero outer stubs, which are still the same length as the stock or supercharged cobalt axles and although I had to offset the block/F40 to the passenger side just shy of two inches everything lines up with plenty of room for CV joint play.
Hindsight being 2020, I would have obtained some later model saab 9-3 9-5 axles and maybe found a working combo with them.. or had a shop remake the turbo cobalt axles, one two inches shorter, one two inches longer. If mine shear, probably on the resplined end, I'll look further into these options or go to DSS and get their SC Cobalt axles..
What axle shop/vendor are you going to be utilizing?
The Cobalt axle issue is due to old info and GM changing the differential offset with the production run of the F40.
People have used the Cobalt axles with the G6 version of the F40 by moving the drivetrain towards the passenger side. You guys are not using that version of the F40.
The issue is at sometime during the production run (2009 or possibly later) GM made the bellhousing on the non-GM metric versions deeper so they could fit larger clutch setups for higher HP and AWD applications. This moved the differential about 1" further from the engine vs. the G6 F40.
Here are a couple of picture of the G6 version (clean) and a later model version.
The Cobalt axle issue is due to old info and GM changing the differential offset with the production run of the F40.
People have used the Cobalt axles with the G6 version of the F40 by moving the drivetrain towards the passenger side. You guys are not using that version of the F40.
The issue is at sometime during the production run (2009 or possibly later) GM made the bellhousing on the non-GM metric versions deeper so they could fit larger clutch setups for higher HP and AWD applications. This moved the differential about 1" further from the engine vs. the G6 F40.
Here are a couple of picture of the G6 version (clean) and a later model version.
A good clutch can fit in the short bell housing right? GM used a dual mass system that took up some space.
