BMW 2002 AND E21 DIFFERENTIAL

[sawn77]

Make:: BMW

Model:: 2002

Location: : marylanDd

i have differential for Bmw 2002 OR E21 part number

331-1204898 in very good condition 

Edited November 26, 2015 by sawn77

[Conserv]

The rear cover is obviously an e21 part but the output flanges appear to say '02 to me. There are good detailed threads on this forum regarding dating and identifying '02-e21 diffs. And...10 out of 10 potential buyers will want to know a.) the ratio, and b.) whether or not this is an LSD, neither of which is currently disclosed!

And, oh yes, this ad would be more correctly listed under "Parts for Sale" rather than "Cars for Sale"!

GLWS,

Steve

Edited November 25, 2015 by Conserv

[sawn77]

How can I find the ratio?

[sawn77]

Thank you for information you provide

Is there any number on differential which can provide the ratio ?

[Conserv]

Thank you for information you provide

Is there any number on differential which can provide the ratio ?

You can turn the input shaft and count, precisely, how many revolutions the output shafts make. Many '02 diffs are stamped with the number of pinion and ring gear teeth on the left front side of the housing. Below is a photo of an e21 diff with complete stampings:

11 S 40

5

8

Which translates to 11 teeth on the pinion gear, 40 teeth on the ring gear (yielding a ratio of 3.64 -- thanks for catching my error, gaius!). The "S" indicates a limited slip unit. And the 5 over the 8 indicates the unit was completed May 1978.

Beware: it's possible to change the ring and pinion set, rendering housing markings irrelevant. Common? No. Possible? Certainly. The sure-fire solution is to simply remove the rear cover and count gear teeth.

Most '02 diffs are 3.64s. Limited slip '02 diffs are quite rare: your price is low for a good '02 LSD, within the range for an e21 LSD, and $500 to $650 too high if it's not an LSD!

Here's a typical thread on identifying diffs:

http://www.bmw2002faq.com/topic/160737-differential-identification/

GLWS,

Steve

Edited November 29, 2015 by Conserv

[sawn77]

thank you so much for the information 

thats help me a lot 

[sawn77]

This is the only numbers I find

11 0

5

5

I guess because of paint the differential some numbers are hide

I don't see s and 4

And also I open the cover and I see big gear has 40 teeth

[sawn77]

These few others picture I took from differential

[Conserv]

11 and 40 make it a 3.64, 5 over 5 make it a unit completed in May 1975. The e21 rear cover is not original to this differential.

Regards,

Steve

[bob02]

Steve,

 

  Were you a dentist in a former life?? You're damn good at pulling teeth with a loving touch:))

 

Bob