WANTED: E36 drivetrain expert

[cfossum]

I have some (fairly) urgent questions with regard to a transmission swap in an E36. We need to complete a project before April, so I need advice with regard to mixing and matching components.
Evidently, the M3 used a ZF transmission while the standard 328 used a Getrag. This resulted in the use of a different driveshaft because the tailshaft output size is different between the two transmissions. Also, the M3 used a rear end which was unique as compared to the standard unit in the 328.
Is there a conversion to put a ZF transmission into a non-M chassis? The non-M chassis would, of course, have the non-M rear end.
Or, is there (out there anywhere) a good place to find a reasonably priced Remanufactured Getrag for a 328?
Perhaps another option is the customize the driveshaft to fit both the ZF tailshaft and the non-M rear end.
I'm really looking for advice for the simplest way to solve this. Any comments? Don't bother telling me to bring it to XYZ shop, we're beyond that. I just need info, thanks!
-Carl

[FredK]

The 95 M3 used a ZF310, 96-99 M3 used a ZF320. The 96-99 328 used a ZF320 and not a Getrag 250.

All 3 of these cars used a transmission output flange with a PCD of 96 mm.

I do not know why you have a Getrag 250 on your 328 with an transmission output flange with a PCD of 78 mm. That does not come as standard equipment. The 323 came with a Getrag, though, with the smaller transmission output flange.

The ZF will bolt up to the 328, because it belongs in there. You will need the ZF transmission and 328 driveshaft (BMW PN 26111227283). Alternatively, you may use a 96-99 M3 driveshaft, but not the 95 M3 driveshaft.

One note is the 328 came with a 240 mm flywheel and clutch that is unique to the 328. It has the same diameter as the M3 flywheel, but it differs to the point that you can't mix and match, for example, an M3 clutch onto a 328 flywheel. If you want to upgrade to an M3 lightweight flywheel (or just have an M3 clutch and flywheel for some reason), it bolts right up to the engine. Just be sure to use all M3 parts with known compatibility with each other. The 95 M3 had a different flywheel and clutch than the 96-99 M3, and the parts do not interchange.

[cfossum]

That is extremely helpful, thank you. I will pass this information along to the gentleman who is doing the work. My interpretation of the problem as it was explained to me on the phone may be somewhat incorrect, but the variations you point out between the different years within the same model could be the very type of information that none of us on the team were aware of. Its also possible that the car in question didn't start life as a 328. Either way, this information will prove to be quite valuable to us.
Thanks again!
-Carl

[jeffw]

Dan Fitzgerald at https://diffsonline.com/ might be a good resource to connect with. He's local and knows that problem space well.

[cfossum]

Thank you, that looks like a good resource for the future. We might have this figured out now, but I'll keep the link just in case.

[FredK]

One further clarification that I did not mention is that the incompatibility of the M3 differential to the non-M differential is unique to the 1995 model year. The 95 M3 has a driveshaft unique to the model year as well, as the driveshaft has a CV joint in the rear instead of a u-joint, and it attaches to this unique 6 bolt diff input flange. If you have a diff with a 6 bolt input shaft, it is from a 95 M3.

The 96-99 M3 has a four bolt diff input flange that is compatible with the 92-95 325i and 96-99 328i.

If you are building a race car, and have a four bolt driveshaft, it may be preferable to use a 96-99 M3 differential, as it is limited slip, unlike the 323, most of the 325, and 328 diffs. I have forgotten if you have to swap out the differential stub axles, as I seem to recall that the M3s had larger diameter CVs on their halfshaft vs. some of the non-M E36s. Swapping out the stub axles, if necessary, is very simple, as they will pop right out since they're retained by a small spring clip.

[joncowen]

Fred is correct. The M3 has larger diff output flanges, at least compared to the 325. Not certain about the 328, since i've never seen them in person.

[cfossum]

Thank you for the additional clarification, I have passed it along. The driveshaft part number and the specific year I believe was the key.