Current status of LSD installs.

[AceAndrew]

@JQ02  I'm sure wavetrack has best intentions, but small case 168mm nuances can be tricky.  However, it can be broken down into two simple variables.  1) LSD Pumpkin width 2) Output flange spline type

 

1) LSD Pumpkin width:  breaks down into two widths. 5.05" and 5.7"                                                                                                                         5.05" applications : OEM 02 LSD's and E21 LSD's.  Since they were "shorter" end to end the case's side caps need to protrude further inboard. 

     5.70" applications : OEM open 02, e21, e30, e36 and LSD versions of the e30, e36.

 

2) Output Flange Spline Count: breaks down into two types.  Early "course" 15-count splines, Late "fine" 27-count splines.

      Early "course" 15-count spline application : All OEM 2002 differentials (including the rare factory 02 LSD).  These were held in via bolts. **

      Late "fine" 27-count spline application : All OEM E21, E30, E36 differentials.  However the only output flange backwards compatible with the 2002 is the E21 output flange.  These were held in with either circlips or retainer clips.

 

**Therefore if you're interested in an aftermarket pumpkin, you need to verify if they are 5.05" or 5.7" wide, AKA if it was designed as a drop in replacement for the E21 or the E30/E36, chances are that it's 5.7" wide (E30/E36) and therefore also the same dimension as an 02 open diff.  However, given the trick to fitting an E30/E36 LSD into an 02 open case is to insert the pumpkin into the case w/o it's cap, then slide in the cap and bolt it on from the inside of the case ... an aftermarket differential design may not allow for that same trick.  i wouldn't know until I had one in hand to tinker with.

 

Right now, over the winter break, I'm rebuilding/assembling five of these things.  If you need reference photos or want to call, you're more than welcome to shoot me a PM.

 

As I said, it's pretty easy when you break it down.  The hard part is getting everyone on the same page on the critical dimensions.

Edited January 4 by AceAndrew

[JQ02]

Thank you very much @uai, @Furry Camel, and @AceAndrew! I really appreciate these details and am glad this knowledge is captured in one place for posterity! What a wealth of knowledge!

[jimk]

Fitting a LSD diff in an open diff case with 4 bolt covers, the diff is wider as @Furry Camel said.  Custom covers a with deeper bearing pockets are someone came up with.  Thats what the footnotes Wavetrak is referring to.

 

Here is @AceAndrew document.  My comment to it is that there is no discussion about determining the total shimming needed for bearing pre-load.  Shims for backlash is one part of the total shims, some are needed on the opposite side.VER-DIFF-1Rev2 4 Bolt.pdf

 

Also the center bolt (02 diff) method and c-clip (E21 open diff) method to secured the output axles won't work.  Axles need to be converted to the E21 LSD design.

2002_Strongest2002LimitedSlipDifferentialBuild.docx

[JQ02]

1 hour ago, jimk said:

Here is @AceAndrew document.  My comment to it is that there is no discussion about determining the total shimming needed for bearing pre-load. 

What a fantastic document. Thanks for sharing @jimk and thanks for having put that together @AceAndrew