rear differential - '76 2002

[DM914]

I'm trying to change out the axle flange output seals in the rear differential -  all the diagrams I have found show a bolt that holds the flange on from the outboard side.  mine doesn't have a bolt -  on either side -  I haven't pulled the unit right out of the car yet or removed the rear plate.  Visually it looks like the shorter differential that should be in the car -  I found an article on the FAQ website about removal of the differential which I'll do ( I have to cut the muffler off yet - but it has a hole in it so no loss )

 

I have new outer seals and bearings and the rubber ring that goes on the inside of the flange - I think that should be all I need -  other than some fluid once I'm done.  I did not plan or replacing the front drive shaft seal or bearing as they are not leaking and are smooth... 

 

Any ideas as to what I might have -  I can try and crawl under and snap a picture or two but it does't look much different than the differential on the OEM BMW site other than it doesn't have a bolt through the flange from the outboard side..

 

I've already changed out the rear wheel bearings ( inner and outer ) seals and all the brake line rubber hardware - wheel cylinders - brakes shoes, drums and e brake cable -  I also took the drive shafts to be serviced / clean and new CV joint rubbers installed 

[DM914]

i found an article in the technical section ( thanks ) that talks about the various differentials in the cars 

 

Variations and how to recognize them:

All 2002/1600 diffs have 4 bolts holding the side covers and the output flanges are held in by a large central bolt. CV's are attached the output flanges with 6 - 8mm bolts.

Early e21 ('77 and '78) 320i's have four bolts holding the side covers, but the output flanges are held in by a C-clip inside the diff. These diffs usually have 8mm bolts for the CV joints but some use the later 10mm bolts. These early diffs are the same width as the 2002 diff so no spacers are necessary if you are putting one in a 2002.

 

 

So by reading this I can be safe to assume that the might have a E21 earlier version because the CV joints do connect with 8mm hex head bolts -  

 

My question now is will the bearing and seals that I bought for my stock 1976 differential work on the early version E21 differential ?   

[Conserv]

27 minutes ago, DM914 said:

i found an article in the technical section ( thanks ) that talks about the various differentials in the cars 

 

Variations and how to recognize them:

All 2002/1600 diffs have 4 bolts holding the side covers and the output flanges are held in by a large central bolt. CV's are attached the output flanges with 6 - 8mm bolts.

Early e21 ('77 and '78) 320i's have four bolts holding the side covers, but the output flanges are held in by a C-clip inside the diff. These diffs usually have 8mm bolts for the CV joints but some use the later 10mm bolts. These early diffs are the same width as the 2002 diff so no spacers are necessary if you are putting one in a 2002.

 

 

So by reading this I can be safe to assume that the might have a E21 earlier version because the CV joints do connect with 8mm hex head bolts -  

 

My question now is will the bearing and seals that I bought for my stock 1976 differential work on the early version E21 differential ?   

 

Certainly all the U.S. 1976 49-state cars received the 3.90 differential (39-tooth ring, 10-tooth pinion), which, but for the ratio, is identical to the early e21 differential.  I've heard reports that some U.S. 1975 cars -- those are cars manufactured September 1974 through August 1975, although I'd bet the e21 differential arrived with the arrival of the e21, about May 1975 -- may have also come with the e21-style differential, even though they had a 3.64 ratio.  If that's true, then I would guess the U.S. 1976 California-only cars ALSO received the early e21 differential, even though they had the 3.64 ratio.  I'd look to the e21 differential parts schematics and see if the early e21 cars ('75 through '78) use the same parts that you purchased -- I suspect the bearings and seals are the same.

 

Short form?  At least U.S. 1976 49-state cars carried the e21 differential, but for the ratio, and the rear housing cover...

 

Regards,

 

Steve

 

[TobyB]

Pull.  It has c- clips.  I have had to pry, then strike the pry bar to break them loose sometimes.  They stick.  You won't hurt them.

 

Then, your seals will work, no hassles.

 

And Steve, you and I differ on this one- the early E21 used a 2002 differential, just the 'very late style' 2002 diff!

heh

And yes, the very late 2002/ early E21 diff had 8mm bolts, with threaded holes in the flanges.

 

t

 

[ray_]

All that work is harder on the front differential.

 

 

Cheers,

 

(that's ok; I'll show myself out!)

[jimk]

43 minutes ago, ray_ said:

All that work is harder on the front differential.

 

And there isn't much air flow thru the rear grills.

[Guest_anonymous]

The '76 differential stub flanges are held into the diff by circlips at the inboard end of the splined shaft inside the casing. The clip need to be removed to take the flanges off. If it is an e21 diff the stub flanges have a friction ring around the splined shaft holding the in, these flanges can be removed as Vice President elect Toby says, pry them off. In either case it will be easier and cleaner to remove the diff from the car to service the seals.

also..... The seals and o-rings are the same.

Edited December 3, 2016 by Guest_anonymous

[Guest_anonymous]

This is a '76 flange, you can see the groove for the circlip at the end. I had them cut for a ring groove at 15mm for using them in an e21 LSD to match the e21 stock stub flange

 

 

[Conserv]

16 hours ago, TobyB said:

Pull.  It has c- clips.  I have had to pry, then strike the pry bar to break them loose sometimes.  They stick.  You won't hurt them.

 

Then, your seals will work, no hassles.

 

And Steve, you and I differ on this one- the early E21 used a 2002 differential, just the 'very late style' 2002 diff!

heh

And yes, the very late 2002/ early E21 diff had 8mm bolts, with threaded holes in the flanges.

 

t

 

 

I guess it depends on one's point of view, Toby!  ?

 

Since '02 production was winding down in 1975 -- with the exception of 1502's and U.S.-spec cars -- just as the European-spec e21 was arriving, I view '02 "development" as ceasing and e21 development as commencing.  Hence, the new E21 head (is that name simply a coincidence or is it based on the intended application?), the C-clipped differerential output shafts, the front seats, and more seem like BMW's "future," but thrown into the late U.S.-spec '02's.

 

But that's just a viewpoint....?

 

Best regards,

 

Steve

 

Edited December 4, 2016 by Conserv

[Mark92131]

On 12/3/2016 at 10:06 AM, Conserv said:

 

Certainly all the U.S. 1976 49-state cars received the 3.90 differential (39-tooth ring, 10-tooth pinion), which, but for the ratio, is identical to the early e21 differential.  I've heard reports that some U.S. 1975 cars -- those are cars manufactured September 1974 through August 1975, although I'd bet the e21 differential arrived with the arrival of the e21, about May 1975 -- may have also come with the e21-style differential, even though they had a 3.64 ratio.  If that's true, then I would guess the U.S. 1976 California-only cars ALSO received the early e21 differential, even though they had the 3.64 ratio.  I'd look to the e21 differential parts schematics and see if the early e21 cars ('75 through '78) use the same parts that you purchased -- I suspect the bearings and seals are the same.

 

Short form?  At least U.S. 1976 49-state cars carried the e21 differential, but for the ratio, and the rear housing cover...

 

Regards,

 

Steve

 

 

I can confirm my 1975 BMW 2002 VIN 2367567 had a 3.64 ratio e21-style differential (C-clip output flanges) from the factory.

 

Mark92131

 

 

[DM914]

that kind of what mine looks like minus all the dirt and grim and the fact it's still in the car   -  I'll pull it later this week so I can replace the seals -   I have rear cover gasket and the seals and the rubber O-rings that go inside the bolted flanges ...  once it's out it should be pretty easy to figure out - 

 

thanks for all the help by the way...  after I get this done I'll start working my way mechanically to the front of the car ...good thing we have long winters gives me lots of time prior to next springs driving season to get things sorted out..