E34 to E30 G260/5 output interchange etc

[Maybe Magpie]

BLUF: Got a G260/5.16 -TNZ 23001221332 out of a '90 E34 w/M20B25, output shaft 23211228296. 96mm flange vs 78mm on the 260/5.15-TNW 23001221205 with output shaft 23211228297. Will a 78mm pop on there or do I need to hunt down and change out the output shaft or what? Do I need to futz around with internals more if I swap the output shaft itself? Both are late M20 cars, my e30 is a 12/87 M/Y '88.

Detail: found a thread about this exact problem that's ancient, but the fellow posting in it didn't elaborate on the actual differences in spec - my local E30 specialist has said he is confident output flanges/spline sizes should interchange so that if I get a 78mm flange I should be good to go with the regular E30 325i 5-speed driveshaft I was gonna grab a rebuild/serviceable u-joint version of (26101226433, L=1483mm) but I wanted to figure out if that was the case or not for real given that thread mentioned needing (minor) machining work. The driveshaft shop also said they could whip me up a 78mm flange if need be but obviously if that wouldn't fit the output shaft that's no good. I'm also not sure if I could just put an E30 output shaft in the E34 G260 and have all the mechanisms still line up, so if anyone knows that'd be great.

HC13 05-1990 and 1113 12-87 are the respective catalogue codes. All the differences between the transmissions I could find in the ETK are as follows:
E34 front:
02 synchro: 23231224325
E30 front:
02 synchro: 23231228097
Synchro 24 (23231228097) and 27 (23231228096) are the same on both cars.

E34 rear:
output shaft: 23211228296
03 synchro: 23231228096
09 synchro: 23231224325
output flange: 23211228038
E30 rear:
output shaft: 23211228297
03 synchro: 23231228096, same as on E34
09 synchro: 23231228097
output flange: 23211228298

Inner gear shift parts:
The E34 only has screwplug M22X1,5 23311224238 valid, the E30 has that and M24X1,5 23111228309 valid. E34 has 03 Roll Pin 07119941381 6x28 and 03 Spiral Tension Pin 23221203745 6x24 as valid, E30 only has 03 Roll Pin 7119941381 6x28 as valid on the first set of inner parts.
E34 uses the same 6x24 spiral tension pin for shift rod components, E30 uses the 6x28 on the second set of inner parts.


Any recommendations or info, or am I best off trying to swap this (functional) G260/5.16-TNZ for a G260/5.15/TNW?

Thanks in advance. This is my last holdup to 5-speed.

Edit: I also found CATuned sells an adapter - is this a better bet or should I do it more factory do you think?

[reelizmpro]

I don't know if the shaft on the E34 Getrag is different but I don't see why it would be. As long as the shaft splines are the same then the small and large flanges will interchange. I have done this on one of my transmissions so I can run the larger guibo.

[Maybe Magpie]

I don't know if the shaft on the E34 Getrag is different but I don't see why it would be. As long as the shaft splines are the same then the small and large flanges will interchange. I have done this on one of my transmissions so I can run the larger guibo.

That's my point of confusion - are the splines always the same? The post I saw lead me to believe they aren't, and at least the support portion/un-splined end is larger(?), plus the differing part numbers. Trying to clarify before I roll the dice on parts.

[TobyB]

No help here- I have discovered that the (spline) answer will vary depending on mfg. date.
So taking things apart, counting splines, and trying it to see if it works is sometimes the only answer.

t

[varg]

Best I can do for you is this picture I took when I did my output shaft seal 5 years ago. You can get the spline count from it and compare it to yours. I believe my transmission is out of a '89 325is


Realoem interchange for the output flange:

https://www.realoem.com/bmw/enUS/part?id=1113-USA-02-1989-E30-BMW-325i&mg=23&sg=15&diagId=23_0145&q=23211228298

[Maybe Magpie]

Best I can do for you is this picture I took when I did my output shaft seal 5 years ago. You can get the spline count from it and compare it to yours. I believe my transmission is out of a '89 325is


Realoem interchange for the output flange:
https://www.realoem.com/bmw/enUS/par...&q=23211228298

Thank you, I'll have to check next time I have access to the gearbox (it's across town at a family member's shed). I hazarded the CATuned 96-78mm adapter doohickey to see if that'll work out for me - if it doesn't I'll try to get my mitts on the medium flange and see if I can fit it on there.

[Maybe Magpie]

Following up: Confirmed with an E30/2002/E28/E24/etc specialist shop that the flange splines fit both size flanges across multiple years, verified by them swapping big and small flanges on and off multiple G260s they had laying around. I'm not sure if that's true for all G260s, but it seems to be true for most of them. I opted to go with the more cost-effective CAtuned adapter as said because the appropriate flange is triple the price - if it doesn't work I'll have to get one, but I'll follow up again if it's smooth sailing.

[Maybe Magpie]

Following up: Confirmed with an E30/2002/E28/E24/etc specialist shop that the flange splines fit both size flanges across multiple years, verified by them swapping big and small flanges on and off multiple G260s they had laying around. I'm not sure if that's true for all G260s, but it seems to be true for most of them. I opted to go with the more cost-effective CAtuned adapter as said because the appropriate flange is triple the price - if it doesn't work I'll have to get one, but I'll follow up again if it's smooth sailing.

Ended up not using the adapter and will likely return it. The place I ordered the serviceable 78mm shaft for my car from (which would be 2792-433N, a PTI unit they were a distributor for) screwed up and sent me the wrong unit despite giving them the right info. I was given the one for 6/'88 and later M/Y '89 cars. PSA: PTI 2792-733N does not match OE BMW P/N 26101226433, and is incorrect for my 12/87 M/Y '88 — doesn't fit the captive studs on the body and the half lengths are wrong for the early-late cars, as it were. Thankfully the RMA was easy-peasy and the folks at HDT Auto both honored the sale price I had gotten around Black Friday and eagerly made it right really quick and got me a replacement in short order, so only mildly inconvenient.

As I had to return and change out which one I was getting anyway the shop I was working with on the swap advised I just stick with 96mm flange so as to not need to source a new output flange or have one fabricated, as they were iffy on the adapter with 25+ years of 02/E30/E36/etc specialty experience. We instead went with PTI 2792-425N - technically an application for an '88 325E but essentially identical to 2792-433N, just with a 96mm flange instead. Bolted right up.

Also worth noting is that everything was plug and play except the shift carrier arm, the E34 version is about 3 inches too long! Thankfully the shop I worked with's head honcho is a fab guy in both senses and gave it a chop and welded it back up to appropriate size in like half an hour, and it works smooth as butter. Some beefy Rogue Engineering transmission mounts for an E46 application also worked perfectly with my G260 and are nice and firmer than stock while being more street-friendly than poly or the like, NVH is minimal. With the DSSR and adjustable SSK from garagistic I got, I'm pretty happy with the setup I have now - the shop had to put a little bit of a bend in the DSSR to clear the 96mm flange and guibo but it works a treat in the end.

Anyway, hopefully somebody with this or a similar problem in the future finds any of this information useful so they don't have to go on all the snipe hunts I did to figure it all out! The end.