Getrag 250 driveshaft

[thepoloplaya]

Quick question, got a m50 with a getrag 250, which driveshaft would swap in with no modifications? Im currently using an e30 back half, with an unknown front half. The setup works, but the U-Joint is on its way out. I have tried an e36 front half and e30 back half, would I be wrong in assuming using a complete e36 driveshaft will work out?

[FredK]

A complete E36 325i driveshaft will work.

[smooth]

An e36 325i driveshaft *won't* work if he's using an e30 differential. he needs to find a driveshaft with u-joints on the end and e36 325i driveshafts have the cv bolt arrangement. a stock e30 driveshaft is going to have the correct u-joints but the input flange hole size will be 10mm instead of 12mm. and an M driveshaft with the correct u-joints is going to have the correct 12mm holes in the input flange but the it's going to be the larger flange than the getrag 250's output flange.

there is no driveshaft that will just drop in without modification for the setup described.

hopefully this information will clarify more than confuse:

Driveshaft
Driveshafts come in many flavors. The driver of which driveshaft you should use boils down to availability, ingenuity, and what transmission you are using, as the transmission output flange (the triangular flange at the rear of a transmission) differs in size between cars.
The brainless way to go about this is to say, use the driveshaft that came with the transmission on the car you are using. It is almost foolproof.
But, if you want to get down and dirty because you want to save a few bucks, or a driveshaft is hard to find for some reason, here is a summary of what should go into selecting the proper driveshaft. First, you determine what transmission you have. Second, you determine the size of the output flange (the triangular flange on the rear of the transmission). It is either 78mm or 96mm bolt circle diameter (BCD). Third, from the output flange size, you choose the appropriate driveshaft. Fourth, take into consideration the size of the bolts that are required. If you put a 10 mm bolt into a hole meant for a 12 mm bolt, you will need spacers. McMaster Carr (www.mcmaster.com) sells plain bearings that would be appropriate for this purpose. Of course, in my opinion, the best thing would be just to use the correctly sized bolts for the correctly sized transmission output flange, flex disc, and driveshaft.
The Getrag 240 (as found in the E30 318is) has a 78 mm BCD output flange. The Getrag 260 has a 78 mm BCD output flange in ALL 325i, early (<6/86) 325e The Getrag 260 has a 96 mm BCD output flange on late 325e (6/86+) The Getrag 250 has a 78 mm BCD output flange The ZF 310 and 320 both have a 96 mm BCD output flange

All E36 driveshafts have 12 mm bolt holes. The E30 M3 driveshaft has 12 mm bolt holes. All non-M E30 driveshafts have 10 mm bolt holes.
The E30 M3, 6/86+ E30 325e, 96+ E36 M3, 96+ E36 328i, and E36 328is have 96 mm bolt circle diameter (BCD) input flanges on their driveshafts. The E30 325i, <6/86 325e, and E36 325i have 78 mm bolt circle diameter input flanges on their driveshafts.

-- http://www.e30dohc.com/wiki/index.ph...age#Driveshaft

I just went through sourcing a driveshaft for my zf320 and z3 diff so I can help if you need more information

[FredK]

smooth,

I wrote that section of the e30dohc wiki. I have also swapped the identical setup to the original poster's. M50, Getrag 250, E36 325i driveshaft, stock E30 differential.

All of the E36 325i driveshafts I have seen have a 4 bolt u-joint rear which mates up perfectly with the E30 differential input flange.

The S50US E36 M3 came with a 6 bolt CV joint rear, which is indeed incompatible with the E30 differential input flange.

[smooth]

sorry about that misinformation

for penance I just crawled under my'94 sedan in the mud to confirm that the driveshaft does indeed have a 4 bolt flange :D


edit: also, thank you for your contribution to that wiki. it has helped me immensely with my swap.
in case this comes up, does it matter if he sources an e36 325i driveshaft from a manual or an auto?

[FredK]

haha, it happens. As long as the original poster gets the info he needs, no worries.

[smooth]

I sent you an PM regarding proper CSB orientation that isn't covered in the wiki. If you have an opportunity to address my questions I'd appreciate it. I didn't want to hijack the thread :)

[thepoloplaya]

Ok cool thanks! As far as center bearing, do I use the e30 one or e36?

[FredK]

E30