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swapping LSD in sierra Diff
gavin174 - 25/8/10 at 07:03 PM

as title really...

Is it possible to take the LSD from one diff and fit into another.

I have 2 lsd's the same ratio and wanted to change one.

Thanks in advance

tomgregory2000 - 25/8/10 at 07:08 PM

as far as i understand, you unbolt the lsd unit from the back of the crown wheel and bolt it on the new one and dont forget to change the pinion as well to match

BobM - 25/8/10 at 07:32 PM

quote:
Originally posted by gavin174Is it possible to take the LSD from one diff and fit into another.

I have 2 lsd's the same ratio and wanted to change one.
Yes, not too difficult. You don't need to touch the pinion if it's the same ratio - do double check this, I had a diff clearly labelled 3.38 that was a 3.62!!

Drain the oil, take the back cover off and then remove the circlips holding the shafts in each side. You can then slide the output flanges out and pull out the crown wheel. As stated the LSD bolts onto the crown wheel.

wilkingj - 25/8/10 at 09:06 PM

quote:
Originally posted by tomgregory2000
as far as i understand, you unbolt the lsd unit from the back of the crown wheel and bolt it on the new one and dont forget to change the pinion as well to match


And dont forget to shim up the backlash on the pinion when you fit it to the new case.
Otherwise you could get premature wear and a lot of whining from the diff.

I would keep crown wheel and pinion as a matched pair, as they wear out together as a pair. A bit like putting new tappets in with a new Cam.

None of its rocket science, just set it up correctly.


mark chandler - 25/8/10 at 09:18 PM

Took me a couple of hours, needed a long socket for the pinion nut so got a shallow air socket from Halfords, sliced the top off and welded a bit of 2" scaffold tube between the two halves, bingo nice long socket to fit.

Wire brush and soak the side adjusters a few days before stripping, I also needed to add a little heat to release one side, was able to use a bit of rod across the teeth to undo.

New seal kit was £5 from Ebay I think.

No special tools required really, do not attack with a hammer !

Regards Mark

snapper - 26/8/10 at 06:17 AM

Gavin you DO need to swap crown wheel and Pinion together as the are a matched pair, any wear difference between the two sets could wreck one in minutes

Liam - 27/8/10 at 05:05 PM

Find an open diff of the ratio you desire, then put the LSD mech into that diff (as opposed to putting your desired ratio crownwheel and pinion into your existing LSD case). That way you dont disturb the pinion shim setup in the case and only have to worry about setting the crownwheel-pinion mesh with the adjustable output shaft bearing housings.