LSD Differential

Simeon · Post by **Simeon** » Thu Sep 03, 2009 7:55 am

Hi All
I have been sold a 7 inch Sierra LSD Differential. i have no reason to doubt it is LSD but is there any way I can tell without stripping it down? it does have the bolt on flanges if thats any use.

Thanks

kiwicar · Post by **kiwicar** » Thu Sep 03, 2009 9:15 am

To check hold the diff case in some way, lock the input shaft in some way, try turning one of the drive shafts, if the other drive shaft turns in the opposite direction it is an open diff (or a very very knackered LSD) otherwise it won't turn until you stick about 150-ftlb into the drive shaft, It'll be obvious.
Mike

sidecar · Post by **sidecar** » Thu Sep 03, 2009 9:31 am

Just turn one of the output flanges whilst trying to hold the other one still, if the other one turns in the same direction its an LSD. Also try turning both output flanges in opposite directions if you can just about do this using all of your strength (or if you can not do it at all) then its an LSD. (Unless someone has had the back off it and welded it up!)

I have swapped an open diff for an LSD in my Cob replica, I'm pleased with the results.

Taking the back of the diff is not a big job provided you use the right size torx bit. (I held the diff in a big vice). In my humble I'd take the back off anyway just to check the crown gear teeth for wear. On my diff I just cleaned up the gasket faces with meths, applied some silicon to one face, let it cure for 1/2 an hour then refitted the back plate.

Pete

Simeon · Post by **Simeon** » Thu Sep 03, 2009 6:02 pm

Thanks for the replies,

You'll all be pleased to know it is a LSD