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Diff Preload Problem..

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#1 Pickwah


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Posted 04 February 2019 - 08:06 PM

Evening all

On with shimming my diff following a gearbox rebuild, A+ with the bearings marked "thrust" on the sides.

Trouble I'm having is with the diff pushed all the way to the clutch side, diff cover and end cover fitted and torqued with a gasket.. the opposite end cover (Speedo side) reads different measurements in different places of the cover! In some places between the bolts which are only finger tight I can only squeeze a 2thou feeler in yet in one place I can get up to 8thou!

I have shimmed one before with no issues!

Any idea?


#2 Ethel


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Posted 05 February 2019 - 01:38 AM

Check the casing all goes together true, without the diff inside or gaskets?

Check the bearings are seated square on the shafts?

#3 Dusky


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Posted 05 February 2019 - 07:29 AM

Maybe check if no threads are pulled up in the casing.

#4 Cooperman


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Posted 05 February 2019 - 05:57 PM

Don't worry too much about this.

Those bearings are huge and well over-size for the loads they take. In fact I have never seen one of those bearings fail in service, even in very hard use.

So long as the diff assembly can't 'float' from side to side there will be no issues. Just shim it as best you can, fit the new gaskets. So long as you don't put any pre-load on the diff it will be fine.

Despite what others will say, I have fitted a non-matched diff cover to a gearbox when one got damaged during a rally and just tightened it up with all new gaskets and it worked for a very long time before coming apart for an engine rebuild. I re-used the non-matching cover again and it was still OK.

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