Cost to rebuild your differential

[MrGumby]

There's been a few people ask for a quote to rebuild their rear diff and instead of sending everyone a list, I figured I'd create a thread for those who ask as well as reference for those who want to attempt it themselves. If you decide to go at it on your own, this is the thread I made as a bit of a how to with some tips & tricks. We'll start with parts.


Pelican parts:

Seal and gasket kit $83.95
33-10-1-203-002

Front Pinion Bearing $19.00
33-12-1-468-895

Rear Pinion Bearing $16.00
33-12-1-468-894
**1976-8/78 only**
**9/78-1983 Not available through Pelican**

Carrier Side Bearings $12.75 (each-you'll need 2)
33-13-1-213-892

Crush Sleeve $6.50
33-12-1-200-259

Lock Plate $2.50
23-21-1-490-120

Inner bearing from 9/78-1983
Maxmillion Importing
33-12-1-206-739 $41.16


Here's a list of limited slip parts that would possibly need replacing

Diaphragm Spring (2) $28.35 each
33-14-1-206-307

Inner Disc (2) $47.71 each
33-14-1-203-806

Outer disc (2) $29.23 each
1.9mm 33-14-1-203-803
2.0mm 33-14-1-203-804
2.1mm 33-14-1-203-804




Labor for bearings & seals- $100

Labor for bearings, seals & LSD parts- $150

Labor for bearings, seals, LSD parts and gear ratio change- $200
***additional shims will be needed for gear ratio change***

Shipping will be at your cost although I do have dock shipping available
through my work which helps quite a bit.
If you want to get a shipping quote beforehand, the box will be roughly these dimensions: 12x12x18 60lbs 85286 ZIP


The easiest way to go with parts is to order them from the respective supplier and have them shipped directly to me, I'll provide a seperate shipping address when the time comes.

Let me know if there's something I'm leaving out of the above list or if you have any other questions

-Bill

[jjgbmw323]

Ok...I will be wanting you to build mine...lets get together on this in a little bit...I am gearing up right now for the engine swap.

I have a 3.91 LSD and an ALPINA Dual finned diff cover replica that I want to send you....

[jimjim69]

My 188mm spool is here now. I just need to get out of doner diff now
***additional shims will be needed for gear ratio change***
How will we know what shims we will need on hand for my diff ?
I may have to make them.

James

[MrGumby]

Ok...I will be wanting you to build mine...lets get together on this in a little bit...I am gearing up right now for the engine swap.

I have a 3.91 LSD and an ALPINA Dual finned diff cover replica that I want to send you....

Ready whenever you are, just let me know!

My 188mm spool is here now. I just need to get out of doner diff now
***additional shims will be needed for gear ratio change***
How will we know what shims we will need on hand for my diff ?
I may have to make them.

James

Make shims? Basically it's a matter of setting it up & checking the wear pattern. The problem comes to the inner pinion bearing and the shim that's below it. I'll probably buy a inner pinion race and machine the O.D. so it slides in and out without force and use that for the initial pinion depth and wear pattern set up.

********UPDATE ON PARTS AVAILABILITY*********

BMW only bearing is not BMW only!!!!
Maximillian Importing Company has the bearing!

********UPDATE ON PARTS AVAILABILITY*********

BMW only bearing is not BMW only!!!!
Maximillian Importing Company has the bearing!

[MrGumby]

Bumping this thread too.

[jrcook320]

Excellent thread, this (and the other) absolutely needs added to the faq. I'll get there soon.

Outer disc (2) $29.23 each
1.9mm (25% lock up) 33-14-1-203-803
2.0mm (50% lock up) 33-14-1-203-804
2.1mm (75% lock up) 33-14-1-203-804

This seem logical and is something I have speculated might be true, but is this verified as how BMW got different lockup percentages? Changes to ramp angle seems like a better method for lockup changes.

I have the 2.1mm discs for my rebuild.

[MrGumby]

It's purely logical speculation. If someone has genuine BMW information on this, please post it up.

[pommeree]

"Slip torque is adjusted with outer plates ...
plates are available in three different thicknesses"

I believe they're used to make modest changes to bring slip torque to within spec.
I don't believe that the individual plates have the dramatic effect on slip torque as Bill has shown above.
[EDIT] Margin on the LSD is between 22 and 36 ft/Lbs. so while maybe not as dramatic as Bill's chart, I bet the difference would be significant.
Pack a pair of 2.1s in there!

Blue book excerpts below ...

[MrGumby]

Thanks, info is fixed now.

[pommeree]

Just for grins, when I was replacing seals on mine, I put my beam-type torque wrench to one output flange and secured the other.
I could get the clutches to slip with a loud 'clack-clack-clack' at about 19Lbs.
Not very scientific ... but fun.
We'll see how she behaves once I'm actually driving it. Otherwise it's going in a crate to you Toyo!

[milovanov]

I assume 2.1mm means 33-14-1-203-805, not 33-14-1-203-804, right?

[midlifebmw]

Wondering what the cost would be to get a open 3.64 diff converted to lsd.... or swapping the ring/ pinion from a 3.64 into a 3.91 lsd diff to get the drop in ratio.

Possible? Pissable? (that's what I had tried to correct in my typing about 4X just now, may be a Freudian slip)

[Tombonetoo]

Hello Mr Gumby

i am replying to an old thread/post of yours. Do you still rebuild/reseal BMW differential boxes? I have a '76 BMW 2002 with a leaky differential. Appears to be coming from the front drive bearing area. I am very mechanically inclined, but after reading your write-up, thought best that sending it to you may be the better option. Let me know.

Best,

Tom Carbone
Fort Worth Area

[dinenoj]

MrGrumby, are you still around rebuilding older BMW differentials?
say from a 1976 2002.