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Sierra Diff Ring & Pinion Swap ???
tilly819 - 10/2/13 at 10:12 AM

Hi all.

I have a 3.9 open diff in my car at the moment and a 3.6 LSD on the bench. I was just wondering does anyone know if it is possible to swap the ring and pinion gears over so i can make a 3.9 LSD?

cheers

Tilly

[Edited on 10/2/13 by tilly819]


mookaloid - 10/2/13 at 10:43 AM

I'm sure it's possible but setting them up is a bit tricky with end float and preload stuff I think?

There was a guide to assembling them kicking around here somewhere ...


ReMan - 10/2/13 at 10:44 AM

I'm sure it is.
Although I did'nt build it I've got a 3.38 LSD


mark chandler - 10/2/13 at 11:15 AM

Yes, easy enough to do yourself if you are not to precious on settings.

On the basis that my little car will only do low miles and everything in the diff was pre-worn I set everything up so it was binding slightly then backed off a tad.

The only exception to this was setting up the pinion, this has a crush washer so you tighten until all float is removed, if you overdo it then you can put the crush washer on a rod and gentle reform it to make it a little wider.

For the pinion nut I got an impact socket for a couple of ££ from halfords and grew it by cutting off the driven end and inserting a couple of inches of scaffold tube as you need a very deep, expensive socket otherwise.

Hardest part is undoing the adjusters either side, soak in decent penetrating oil and warm the outside with a blow torche before trying to shift or the lobes break off, I used a rod across the adjuster, better off with the correct tool, they are on eBay for not to much money sometimes, along with a seal set.

Regards Mark


tilly819 - 10/2/13 at 04:46 PM

cool, that sounds very promising. Iv found a strip and rebuild manual which has all the exploded diagrams in and torque settings etc.

cheers

tilly


Johneturbo - 10/2/13 at 06:10 PM

just put the lsd into the open diff then you don't have to mess about with the pinion, only need to set up the back lash


tilly819 - 10/2/13 at 09:13 PM

quote:
Originally posted by Johneturbo
just put the lsd into the open diff then you don't have to mess about with the pinion, only need to set up the back lash


I was thinking of doing that, great minds think alike!

Tilly