Differential ID

pkbinplano

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don't know where else to ask, where are the ID numbers on the differential from a 72 Bavaria. Going to flea bay it but waiting to ID it first. Also what is the going price on these, non lsd ? Thanks
 

x_atlas0

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The diff tag is on the bottom right, it is a flat section on the bottom edge of the unit, about 3/4ths of the way towards the back. (if th input flange is the front)

The stamped tag will say if it is LSD and the ratio.

There was a thread about this a while back, with pictures. I suggest you look it up.
 

x_atlas0

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I checked on the thread I mentioned, and the pics are all long gone, since it was primarily ebay pics.

For the actual part numbers, in the pic decoupe posted, you can see them on the top, in line with the output flanges. You can then check these part numbers on realoem.
 

Bill Riblett

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Diff ID

For E3 and E9 diffs, the diff. ratio, expressed in numbers of gear teeth, i.e. 39:11, is stamped on the right side of the diff, in front of the output shaft on that side (the opposite side of the output shaft from the area circled in the picture above). Limited slips have an "S" stamped there. These markings are pretty faint and usually pretty well hidden under paint, grime, etc.

The cast numbers on top of the diff aren't useful for ID.

The tags and painted "S" didn't come until the E12/E24s.

Diff ratios:
3.64 = 40:11
3.45 = 38:11
3.25 = 39:12
 

Malc

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I have an LSD and "normal" diff in the shed....
Time for more pictures?
Malc

Update:

Pictures taken, though there are some differences in the stamped and the cast in numbers. However the main part number 12243301800 remains the same.

1.. Casting marks on LSD Diff.
Note the sideways "S" above "15 BMW". The white painted "E" (Ersatz?) shows it is a BMW rebuilt unit?

e02eb752a7336cb92792accc71daaf10.jpg


2.. Casting marks on the original out of the bucket

c89f8beb9602fe188fd800601f9b54b9.jpg


3... Tried to highlight and show the markings on the LSD diff, sorry a bit of a mess, but basically
11 43 - 3.09 Ratio on the rear face?
A9 80 - No idea, unless it's a rebuid date?
E - For Ersatz (spelling) for part/rebuilt part

92b820231e4e7b5c22f1cfe147674a36.jpg


4... Numbers found on the original Diff these were the only ones I could find.
12 39 - 3.25 ratio I assume
14 - No idea
2 - Sideways, again no idea

f9eb44c90414eb5dfabea1b811fe79dd.jpg
 

pkbinplano

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Thanks

I thinks it's a common 3.64. I think I'll just send it to the crusher with the car. Last call for motor parts, another one bites the dust.
 

stephan.s

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Borrowing this thread to ask a question about a sideloader differential I've come by. I've spent several hours scanning google for info about these, but the ID process is still a mystery to me.

I haven't baught it yet, since its 19 mile roadtrip to pick it up, and unless it's a lsd, it's not worth the time. So all i got is this pic to go by:
image.php



It's from a 77 E9 3.0 Automatic with 3.45 apparently. Was thinking of using it on my 79 e24. Any thoughts?
 

x_atlas0

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Borrowing this thread to ask a question about a sideloader differential I've come by. I've spent several hours scanning google for info about these, but the ID process is still a mystery to me.

I haven't baught it yet, since its 19 mile roadtrip to pick it up, and unless it's a lsd, it's not worth the time. So all i got is this pic to go by:
image.php



It's from a 77 E9 3.0 Automatic with 3.45 apparently. Was thinking of using it on my 79 e24. Any thoughts?

That picture isn't enough to go on. The part number shown is for the differential housing, rather than what is actually in the case. You need a picture of the bottom-right edge tag to determine if it is a LSD and what ratio it is.
 

Bill Riblett

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Nothing in the picture is of any value for identification. All those numbers were cast in the part. what you are looking for are the stamped numbers, like Malc shows highlighted in his post above.
 

sfdon

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a [enhanced a bit] pic for you..

hope this helps.
 

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PaulinPa

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Did you "enhance" the "S" or is that what it actually looks like when you remove the 40 years of crud?I thought it was on top,this is much easier to find!Thanks for posting!
 

sfdon

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The "S" was getting fairly worn , so I used the paint program to fill in missing or faint parts.
 

stephan.s

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Thanks for your reply. I was hoping those numbers where enough to identify it, but I didn't have my hopes up.

According to the seller says there are no numbers/letters in the area you describe, and he isn't being very helpful at all, so I'll keep looking for another one. Thanks thou. At least now I know how to identify one. ;)
 

stephan.s

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I'm gonna use this thread to ask a few questions, rather than starting a new one.

I finally got my hands on a LSD, 3,45 ratio.
Is it possible to swap the LSD unit from the 3,45 to the original 3,25 on the car, or do I need to replace the bearings if I do? (Want to combine it with a Getrag 265/6 OD gearbox) How about oil?

And how do I identify the lsd unit? Not sure what to look for. Just want to check to see if it's welded or a real lsd.

One last question; according to the seller, it was restored 3 years ago and changed to about 70%. How do i check the percentage? And how do I lower it? Think 70% is a bit much for a cruiser.

Thanks

edit: Unless it's an original CSL or later E9 with the 75% lock. If so, is it identifiable? There are no stampings on the case to how much locking there is.
 
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sfdon

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You could try asking Pete at "Petes Gear Shop" in Haywaed CA
 

x_atlas0

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I'm gonna use this thread to ask a few questions, rather than starting a new one.

I finally got my hands on a LSD, 3,45 ratio.
Is it possible to swap the LSD unit from the 3,45 to the original 3,25 on the car, or do I need to replace the bearings if I do? (Want to combine it with a Getrag 265/6 OD gearbox) How about oil?

And how do I identify the lsd unit? Not sure what to look for. Just want to check to see if it's welded or a real lsd.

One last question; according to the seller, it was restored 3 years ago and changed to about 70%. How do i check the percentage? And how do I lower it? Think 60% is a bit much for a cruiser.

Thanks

edit: Unless it's an original CSL or later E9 with the 75% lock. If so, is it identifiable? There are no stampings on the case to how much locking there is.

As I recall, with these units, the LSD replaces the actual "differential" part of the diff, and can be bolted to any ring and pinion gearset you want, assuming the gears are of the proper diameter and bolt pattern. You will still have to re-shim and may as well rebuild the diff while you are there at that point, as you have to mostly break down the diff to get to that point anyway.

You can easily identify the LSD because it is the only thing (aside from the pinion and ring gear) inside the diff. It is shaped like a coffee can. If it is simply welded, you will still be able to see the internal gearset.

Most of the guys run the OD gearbox with the 3.45 diff. It works out pretty well. You end up at around 2000 RPM at 70 mph using stock tire diameters. (assuming I'm remembering correctly, it has been a few years since I did a serious highway blast with my E9)
 

bluecoupe30!

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So I had some time today, and got under my Coupe and tried to identify what diff is in my '72 CSA. The above posts were really helpful and I have found I have, to no surprise, a 3.64. see photo. But I am curious, has anyone decoded the other numbers etched in and around the 11 40 or 11 38? I see a sideways 2, and a big 3, any ideas?
fullsizeoutput_152.jpeg
 
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