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ant_8u 12-25-2012 02:12 PM

Cause of Whining Differential?
I'm planning on rebuilding my differential before refitting it to the chassis

From what I've read, these differentials have a tendency to whine

Since my car was a non-runner when I got it I have no idea if my diff has any problems.....but I'd rather rebuild it now, than facing the possibility of removing it from the car once it's back on the road

From speaking to other owners I've been told the whining (when present) is caused by the hardening on the crown wheel becoming worn through

The noise will be loudest on acceleration either disappear entirely or become very low on overrun/deceleration

The pinion bearings can also be a problem, but the noise is from the centre of the car (not on one side) and is very short term, i.e. the bearing collapses, the oil leaks out and the differential seizes


Does that sound right that the crown wheel hardening would cause the whining?

Can I do anything to check for this before reinstallation?

I'm planning on fitting new shims, bearings, and gaskets, but I'm a little worried about the crown wheel

As ever, your insight is most appreciated
Thanks, and Merry Christmas to you all

big gear head 12-25-2012 02:34 PM

What kind of car is it? What differential is in it?

Most of the time the bearings will cause the noise. It can be a pinion or differential bearing. Maybe cars in England have problems with the heat treatment of the gears, or maybe the metal is bad, but the gears are usually not the cause here. If a gear is bad it usually shows up as soon as the gears are installed.

ant_8u 12-25-2012 02:56 PM

Car is '71 Triumph GT6
Differential is stock 3.27:1 Item

Here's the exploded diagram for it.......

Rear Axle Centre Details : Axles, Suspension, Drive Shafts and Wheels : Triumph GT6 MkIII Spare Parts Catalogue - Canley Classics

Should I just look for unusual wear in the gears, or can they be heat treated again?

I've got the workshop manual, which I believe shows the dimensions and clearances
As these measurements are for new units, should they still be relied on, or should there be some 'give' in them?

big gear head 12-25-2012 07:18 PM

I don't know about the gears, but I would check the bearings first. If it is the gears they can not be fixed. Plan to replace them.

ant_8u 12-25-2012 09:03 PM


So, as the condition is currently unknown I think I'll do a rebuild with new seals, bearings and shims and see how we go

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