They all work... so for most applications, it really doesn't matter which one you run. It might be best to stick with the GM fluid.
If you plan to drive your car in the sub 40 degree temps, the heavier weight fluid options make the shifter more difficult to move on cold mornings until it warms up. They also likely will reduce your mpg slightly.
I switched to the Redline Shockproof as I am aproaching near twice the rated touque through the F40, and the shockproof line is designed to help in these extreme cases.
This thread was the main source of info for F40 3.09 conversion and I am glad that I found it. I am doing conversion for my Alfa Romeo 156 2.4 JTDm 20V which has 3.54 F40 gearbox. From Ebay I bought 3.09 gearbox from Opel-Vauxhall Insignia 2.0 CDTi "ECOFlex". I read that you are not sure in what cars are 3.09 gearboxes. I found that only "ECOFlex" Opel-Vauxhall Insignia's have that gearbox and Astra K with B16DTU engine. So it is easier to find the gearbox by specific car model searching ECOFlex only.
I also bought another Alfa's F40 gearbox, because housings are not the same, and I am using the car daily, so when I finish conversion I will just put modded F40 to the car.
Also I tried to measure shim preload, and gap between outer bearing ring and the gearbox's housing by putting soldering wire between, putting the 3.09 bearings and 3.09 gear set in 3.54 housing, tightening and tapping top of the housing with rubber hammer, and then removing everything and measuring thickness of the soldering wire. I am hoping that this was good method. Now I will do the same one day when I have time, but everything stock with both gearboxes. I am aiming for 0,05-0,12mm preload but I will find out when I put all back together both gearboxes with stock gear sets. Shims that I have now are: for diff: 1,00mm, 1,05mm, gear set: 1,10mm x1, 1,15mm x2, 1,20mm x3.
On the images are info where to find 3.09 gearbox on which cars and the current gap measurements between bearings and the housing (3.09 gear set in 3.54 housing with 3.09 bearings). Measurements were min and max measure that I got, need do it maybe once more for consistency and taking the average.
I hope that this info will help.
[This message has been edited by fikuna45 (edited 06-03-2025).]
Hello, It was a good idea to use solder wire to determine the shims.
I also bought a used F40 to change the final drive for my car. The used F40 has 3.091 final drive with only 110k kilometers milage. All the gear ratios would be suitable for me. So I will intend to swap the cases of the F40 gearboxes, since the case of the 3.091 gearbox is slightly different to my F40 with 5.545 final drive.
I wonder whether it is easy to pull out the outer tapered bearing races from the casing of F40 without any damage? Should I use an expensive bearing puller which has wide surface (see picture)? Since I reuse the races and the shims, I want to avoid damaging anyone of them.
On the picture I point out the places of outer races for better understanding.
I used modified inner bearing puller like one @fieroguru used. But mine was broken after several attemps. I grinded off too much of material.
So I used hand impact bearing puller with a modified hook (Flattened and near perfectly rectangular so it can go and grab underneath the bearing edge ) and then I hammered out left and then right side alternately little by little until bearing popped out. I did this twice for shim side bearings, and none fo the bearings was damaged nor it had any scratches.
Bearing seat had few minor scratches at the beginnning only until I managed to do it properly.
Of course best way is to use wide bearing puller, because then you are reducing the risk of damaging anything.
Thank you for the response. Today I opened the donor F40. Really interesting to do such kind of projects
I will start also with a budget tool for bearing races pulling. Will I require a press to install the outer bearing races? Or I can just use a piece of wood and a hammer? Best regards,
Good time of the day, I have purchased a 20t press with bottle jack and hope it will get the work done on my F40 gearbox. In the next step I wanted also to purchase the driver set for the bearing races of the shafts, but I found out that the driver should be a tiny bit smaller than the race diameter. Because the bearing race is pressed inside a 62mm hole.
Currently I am struggling to find a driver for this bearing race. Could you tell me which one did you use?
Good time of the day, I have purchased a 20t press with bottle jack and hope it will get the work done on my F40 gearbox. In the next step I wanted also to purchase the driver set for the bearing races of the shafts, but I found out that the driver should be a tiny bit smaller than the race diameter. Because the bearing race is pressed inside a 62mm hole.
Currently I am struggling to find a driver for this bearing race. Could you tell me which one did you use?
Best regards,
Not exactly sure. I know I purchased a bearing race driver kit, but don't recall if I needed to modify one of them. In a pinch you could drive the race most of the way in with piece of wood and a hammer. Then to fully seat it set the old race on top of the new one and use the wood and hammer again.
By the way, after many days of research I found a service manual for F40. It is an official website of Alfa Romeo. There you can find the torque numbers of fasteners and information about the shims and the preload of the differential shaft bearings.
As I mentioned I used improvised puller tool for the bearings, pictures are below. I did not damaged nor the bearing nor the shim. Only thing is that I needed press a little bit plastic oil cap for tool to get in. I pulled one side at a time. I have generic bearing removal tool, only thing that I modified was the hook a little bit. Puller hammer was 32mm wrench.
When pulling it out, my improvised tool needed to be at slight angle and I needed to hold my finger on the hook pressing against housing so it does not pop easily when pulling.
I took a pictures of bearing without plastic oil cap for example, but the principle is the same.
Best starting point for pulling them out is oil channel hole because there you have the most grip and hook can go in there with ease. I know this is not the best way to do it, but for me it worked and I did not damaged anything.
It is 60Nm plus 90 Degrees. I have it from Alfa Romeo's documentation.
Oh, documentation for this transmission exists? I didn't know Alfa even used it. Although... Alfa is a Fiat brand and the transmission came from Fiat & GM's collaboration.
Does Alfa list part numbers for the internal components?
quote
Originally posted by Wasii:
Thank you so much!
By the way, after many days of research I found a service manual for F40. It is an official website of Alfa Romeo. There you can find the torque numbers of fasteners and information about the shims and the preload of the differential shaft bearings.
By the way, after many days of research I found a service manual for F40. It is an official website of Alfa Romeo. There you can find the torque numbers of fasteners and information about the shims and the preload of the differential shaft bearings.
Originally posted by Will: Alfa lists two models which use the 0.62 sixth gear. Is there a place on this site to find the part numbers for those gears?
The 0.62 6th gear on the input shaft is # 12787428. I don't have the part # for the mating 6th gear on the main lower shaft.
quote
Originally posted by rbell2915: I think it would be a good idea if someone took screenshots from those links and post them here for documentation. Never know when the link will die.
I already copied them to word documents for my files. One is 22 pages long the other is 36, so that would be alot of screen shots. The two teardown links are really about how the special tools used for disassembly. Those are the only part #s listed. So they will be helpful if you haven't torn one down, but not super critical.
I already copied them to word documents for my files. One is 22 pages long the other is 36, so that would be alot of screen shots. The two teardown links are really about how the special tools used for disassembly. Those are the only part #s listed. So they will be helpful if you haven't torn one down, but not super critical.
Okay great, it appears that some things on the Internet do not live forever!
Thank you, @ fikuna45. I could build two tools too extract the races.
@Will: I could only find two sources for part lists: the first one is in english, but requires some payment : https://alfa-romeo.7zap.com...ransmission+gears/#2 the second one is in russian and is for free. just look for "CC2.4" and you will find the parts of F40 gear box that was installed in 2.4 Diesel Alfa Romeo with the following ratios: 1st : 3.769, 2nd: 2.040. 3rd: 1.321. 4th: 0.954, 5th: 0.755, 6th: 0.623, reverse: 3.538. https://www.elcats.ru/alfar...8+%D0%9A%D0%9F%D0%9F
@rbell2915: I agree. the links can de closed by Stel lanti s. Since they even make it impossible to get access to servicebox website for small repairers without tax id......... so, I had luck to modificate the links of the service instructions and provide you a printable version :
A couple notes from a geek about recent F40 posts based on my experience rebuilding one four years ago:
I suspect the evolution toward lower transmission oil viscosity and lower transmission oil fill level during the F40 production run was driven by fuel economy, not cold weather shift effort. They even had engine start-stop capability on some later models for the same fuel economy reason.
There is a lot of confusing info about factory oil recomendations, perhaps starting with SAE 70W-90 GL-4, then SAE 75W-85 GL-4 under a wide variety of GM Opel Saab & ACDelco part numbers, but the last factory recommendation for F40 transmission oil was apparently an SAE 70W GL-4 which was Castrol BOT-303 sold as GM 19259104 and ACDelco 10-4037. I first bought the expensive ACDelco stuff, but have since switched to Red Line MT-LV that is a little cheaper and more readily available. It works fine but..
The cold weather hard shifting issue that plagues all F40s is unlikely to be significantly improved by any oil formulation or oil level changes. I believe the hard shifting in cold weather is related to tapered roller bearing preload that almost stops the input shaft in the middle of a shift. Speeding up the input shaft (and all the gears that are meshed with it) from zero is a much harder job for the synchronizers than simply matching speeds that are nearly equal. My transmission shifts swell when it's warm.
Like everybody else I shimmed my tapered bearings to give a little preload at room temperature, which probably gives a little less preload or even a little endplay at operating temp when the aluminum case expands a little more than the steel shafts and bearings. Unfortunately that same effect will give a lot more preload when the transmission is cold and the case shrinks a lot more than the shafts. I used the wrong sealant on my case (anerobic instead of the correct RTV), and my case started leaking at the joint the first season of cold weather - I am confident that increasing bearing preload trying to pull the case halves apart is why later transmissions have extra bolts at the bottom as noted by Fieroguru.
Those Alfa service publications are sweet. When I did my tranny all I had to help was the great info that Fieroguru has published, plus a couple Opel F40 Technical Service Bulletins (recalls 14-E-3074, & 15-E-3183) that had a little bit of the same info as the Alfa pubs, but have since disappeared from the internet.
The tall 0.623 ratio 6th gear has a 61 tooth gear on the input shaft (GM p/n 12787428 per Fieroguru) and a 38 tooth gear on the lower countershaft. I believe the GM part number for the 38 tooth gear is 12787469, & Opel p/n 9007154. There is a German transmsission specialist that doesn't list the GM part number, but does appear to offer these parts (and others) https://getriebeservice-gse...-gangrad-6-gang-z38/. The Russian parts info referenced by Wasii lists a Saab p/n 55563065 for the 38 tooth gear, which also led me to this Italian ebay listing that might be the right stuff (based on counting tooth numbers in the photo) https://www.ebay.it/itm/126...stomid=&toolid=10050. My 1st time on the site so please excuse my format. Hope there's something useful here.
Thanks! Great info! I hadn't had time/bandwidth to dig into either of those pages and follow the leads.
I've found the 12687469 number in parts lists for GM F40s, but while the listing exists, no supplier could ever get one.
It's interesting that you mention a 5556 number, as the '11 and '12 Buick Regal transmissions (entire unit) start with 5556
Neither the German company nor the eBay seller ship to the US, so I've asked both if they can. Since I already have the input gear, it would be great if I could just buy the output gear.
Don't laugh. Although I salute you Fiero guys, my F40 still has the 3.55 final drive from the wrecked G6 I bought to transplant the transmission into my daily driver, a Chevy Malibu Maxx with the standard 3.5L LZ4. I took it apart to inspect, replace all the bearings & synchros, and install a Quaife diff. Lotsa research and wrench work, but no fabrication because GM did all the engineering - it just bolted up. I wanted a big hatchback with a V6 and a stick. I've followed the 3.09 final drive story because I'd consider it if I ever have to remove my transmission for any reason (like a clutch replacement - I've got 46K miles on it so far).
Hi, I started setting the preload on my differential bearings, but I ran into a problem. When measuring the diff bearing preload, do I need to install and torque all of the case bolts? I followed the original F40 gearbox preload measuring procedure, and when I installed the 3 bolts as shown in the instructions, I got the same reading every time. But when I added just one more bolt, the reading changed. I’m not sure what’s happening—does the case twist or something like that?
whith 3bolt installed I got every time like 1.2nm readings on the torque wrench, I installed the thicker shim and still the same Thanks
Originally posted by ManojlO: When measuring the diff bearing preload, do I need to install and torque all of the case bolts? I followed the original F40 gearbox preload measuring procedure, and when I installed the 3 bolts as shown in the instructions, I got the same reading every time. But when I added just one more bolt, the reading changed. I’m not sure what’s happening—does the case twist or something like that?
By defintion, when setting "preload", the width of the bearings on the differential are wider than the opening in the case, so the case is pulled around them and slightly deformed. To get an accurate measurement, all case bolts should be tighened and torqued to replicate the as assembled condition.
My preload torque values as measured from a 0 mile F40, were done in this manner, so only torquing a few bolts will likely result in a different value.
@ManojlO: by 2b all the M8 bolts are meant and by 2c the M10 bolt. I could measure the torque of 2 Nm, if i rotate it moderately. As soon as I started to rotate it fast, the preload was going down up to 1Nm. Kind of strange. The torque to start rotating the differential was aroung 3 Nm.
What kind of tool did you use? After some testing, a torque dial wrench (Tohnichi 6Nm) was shifting torque values by 0.5Nm if some pull of push force into axial direction was applied.
Could you tell me where you bought the new bearings? The bearings have some article numbers on them, but not each of them could be found in the internet. Even an official distibutor of Koyo bearings could not help. The support from Koyo directly told me, that some bearings were designed only for GM and they are hard to get.
[This message has been edited by Wasii (edited 09-12-2025).]
The Russian parts info referenced by Wasii lists a Saab p/n 55563065 for the 38 tooth gear, which also led me to this Italian ebay listing that might be the right stuff (based on counting tooth numbers in the photo) https://www.ebay.it/itm/126...stomid=&toolid=10050. My 1st time on the site so please excuse my format. Hope there's something useful here.
I bought this, and it appears to be the correct gearset. (Where's the modern "party!" emoji?)
Upper & Lower Main Shaft - Gear Case End: Koyo 32007-JR-3YD (35mm ID, 62mm OD, 18mm width)
Upper & Lower Main Shaft Shims - go behind the gear case bearings. The part # goes up or down by 1, the thickness of the shim changes 0.05mm. 24461944 = 0.80mm (thinnest) ... pattern continues 24461949 = 1.05mm 24461950 = 1.10mm 24461951 = 1.15mm 24461952 = 1.20mm (thickness specified on tear down documents) 24461953 = 1.25mm 24461954 = 1.30mm 24461955 = 1.35mm ... pattern continues 24461966 = 1.90mm (thickest)
Does anyone know the GM part number of the shims for the differential? The shim from Alfa Romeo documentation has long lead time. I have currently 1.2 mm and the differential can be easily turned showing only 0.5Nm of rolling torque. It is my second rebuild. In the first one I had luck and should not to change the shims.
I did my swap and 90% of my research was back in 2017 when I first started this thread.
At that time, I was pulling information from everywhere I could find it. I found various items on various websites and took the disassembly drawings, copied over all the part call outs, and then started adding part numbers when I came across them. That is where that page came from.
It was far to long ago to remember which site got be the shim part #s, but I least I wrote them down when I came across them.
Hello. I am a new member with a question about the final drive swap. I have an Insignia A A20DTH ecoFLEX and form the pic fikuna45 posted it's fitted with 3,091 final drive. But I am afraid the gears are too long with this final drive. On third gear at 3000 RPM the speed is 95 km/h, on 6th gear the car doesn't have any power for acceleration at 140 km/h while cruising on the highway. And I am curious why would you all want to swap yours with a 3,091? Aren't the cars more responsive with bigger final drive ratios? Or I am missing something? Or maybe the car will be a lot better with a fine tune of the ECU?
quote
Originally posted by fikuna45:
[This message has been edited by PackMan0 (edited 09-17-2025).]
Hello. I am a new member with a question about the final drive swap. I have an Insignia A A20DTH ecoFLEX and form the pic fikuna45 posted it's fitted with 3,091 final drive. But I am afraid the gears are too long with this final drive. On third gear at 3000 RPM the speed is 95 km/h, on 6th gear the car doesn't have any power for acceleration at 140 km/h while cruising on the highway. And I am curious why would you all want to swap yours with a 3,091? Aren't the cars more responsive with bigger final drive ratios? Or I am missing something? Or maybe the car will be a lot better with a fine tune of the ECU?
The lower gearing is great for very high torque engines, like a v8, with lower torque engines, especially if it's a stock 2.8v6, the engine won't have enough torque to work very well. My 4 speed and 14"wheels had the stock engine at nearly 3000 rpm at 110-115km/h, that is very high, but passing on the highway was still not to great, sometimes I still wanted/needed to shift to 3rd. My new f23 5 speed/larger wheels/turbo 3.4 has highway rpm at 2400, much better sounding and feeling, but enough power in 5th thanks to the turbo to not need to down shift, although I still might for the fun of it. Also technically top gear isn't for accelerating at all, it is for high speed cruising, and ideally enough torque to get up any hills on your highway. Many newer/less powerful automatic cars have a very low top gear, then change down 1 or even 2 gears as you increase the throttle, sometimes even just for hills. My 2001 Sebring is the opposite, it stays locked in 4th (top gear) until about 95% throttle, then it jumps to 3rd and takes off, makes the cruise control rather interesting haha.
I did my swap and 90% of my research was back in 2017 when I first started this thread.
At that time, I was pulling information from everywhere I could find it. I found various items on various websites and took the disassembly drawings, copied over all the part call outs, and then started adding part numbers when I came across them. That is where that page came from.
It was far to long ago to remember which site got be the shim part #s, but I least I wrote them down when I came across them.
I understand. And thanks to this thread I was inspired to do the gearbox rebuild.
Hello. I am a new member with a question about the final drive swap. I have an Insignia A A20DTH ecoFLEX and form the pic fikuna45 posted it's fitted with 3,091 final drive. But I am afraid the gears are too long with this final drive. On third gear at 3000 RPM the speed is 95 km/h, on 6th gear the car doesn't have any power for acceleration at 140 km/h while cruising on the highway. And I am curious why would you all want to swap yours with a 3,091? Aren't the cars more responsive with bigger final drive ratios? Or I am missing something? Or maybe the car will be a lot better with a fine tune of the ECU?
I have Insignia B sports tourer (Buick regal tourx) with diesel engine , 416 Nm (307 lb-ft) (I measured it on Dyno) and 245/45 18" wheels. When cruising long distances at 130 km/h (80mph), I have around 2300 rpm. This is 61% of my nominal rpm. Just for the cruising it is too much.
The turbo of my diesel engine is efficient till 2250rpm, cause according to its spec. the engine has its top torque band between 1750 and 2250 RPM. It means that any speed with the higher rpm than 2250 would be the moment, when the engine would work less efficient. I just have an awkward feeling driving more than 130 km h knowing that my engine is performing at lower efficiency than it is capable of and I am just burning fuel hence money for nothing. Also higher rpm cause a tiny bit more wear on the components. I maintain my car and want that it functions for a long time.
During my trips I measured the engine load with app over db2 interface. On the highway the engine has the load of only around 30%... I made a research about the brake-specific fuel consumption of the diesel turbo engines depending on load and rpm. The engines burn less fuel, if the load is at 2/3 and the rpm is relatively low. So, my aim was to lower the rpm and to increase the engine load on the highway to burn less fuel.
Those are three reasons why I am changing the final drive from 3.545 to 3.091. I calculated, at 130 km/h I should have 1950 rpm. Still in the middle of the top torque band and still it would be at 52% of engine nominal rpm (where the peak power is).
Well, honestly, even with 3.545 that car doesn't have power to accelerate quickly in the sixth gear. It accelerates slowly like a yacht. No one of the passengers feels it. So, I will not be surprised by low torque on the wheels after the rebuild.
I really hope that it would reduce the fuel consumption of the car. Diesel engines of BMW, Mercedes , VW and so on have low top gears for cruising. It means they have proved the concept.
I bought it stock with 70k km (43k miles), on highway it had 6.2 l/100km (38 mpg). Now after some mods it has 4.8 l/100km (49 mpg). I am trying to get the best efficiency on long highway trips from the car to be able to travel with clean confidence and some money left in the pocket
[This message has been edited by Wasii (edited 09-17-2025).]
Originally posted by PackMan0: Hello. I am a new member with a question about the final drive swap. I have an Insignia A A20DTH ecoFLEX and form the pic fikuna45 posted it's fitted with 3,091 final drive. But I am afraid the gears are too long with this final drive. On third gear at 3000 RPM the speed is 95 km/h, on 6th gear the car doesn't have any power for acceleration at 140 km/h while cruising on the highway. And I am curious why would you all want to swap yours with a 3,091? Aren't the cars more responsive with bigger final drive ratios? Or I am missing something? Or maybe the car will be a lot better with a fine tune of the ECU?
When I first did the swap, the engine was a natually aspirated LS4, 5.3L V8 with 382 rwhp and 335 rwtq and the car weighted 2807 lbs. The final drive swap was more about improving the driving feel of 1st and 2nd gears. The lower cruise rpm in 6th was an added benefit.
It really changed the around town feel. It now feels like driving a sporty V8 car vs. it being way over geared swap. With 6 speeds to choose from, if you want more responsiveness, just downshift and/or press the loud pedal harder, or both!
I would do the final drive swap on every F40 swap, but then again I am a V8 guy.
I bought it stock with 70k km (43k miles), on highway it had 6.2 l/100km (38 mpg). Now after some mods it has 4.8 l/100km (49 mpg).
Going from 3.545 to 3.091 will cause more that 12% reduce in acceleration... so if you think it is slow now it will be even worse with 3.091 and you will have to downshift for every overtaking which for me is annoying.
quote
Originally posted by Wasii:
Well, honestly, even with 3.545 that car doesn't have power to accelerate quickly in the sixth gear. It accelerates slowly like a yacht. No one of the passengers feels it. So, I will not be surprised by low torque on the wheels after the rebuild.
(Where's the modern "party!" emoji?)
