Noisy Differential

[Julian Taylor_4995]

The diff on my TR4a makes a chattering noise when it is not under load; so on over run and when crusing. I am sure it makes other noises but this one is becoming intrusive suggesting that I ought to pay attention to it. The diff was a reconditioned unit and it has done around 20,000 miles since. I have jacked the car up and it all seems very sloppy to me. Please could someone suggest what this might need be and how best to fix or adjust it,or who should I take it to to get it repaired?

 

Thank you

[ianc]

Quite likely to be some teeth shed from pinion - can be silent under load, but noisy on the over-run (it's happened to me on 3 occasions)..

If too many teeth get stripped off, the loose teeth can lock the gears - quite dramatic, even at low speed (happened to my brother's TR3 in Wandsworth, many years ago)!

To check, you need to remove the cover, but not so easy on a TR4A.

Don't leave it since every tooth lost on the pinion exposes the remaining adjacent teeth to more load and they will fail fairly soon.

Ian Cornish

[TriumphV8]

There is an older thread, I think SImon with the V8 posted

and a lot has been told there about this topic.

 

You should check the inside quickly and do not drive much till

you have the answer because on a fresh defect the

CWP might be reused but if the parts started eating

each other the price rises for more than 300 GBP

for a new CWP that might be needed.

 

Experts to do a proper refurbish seem to be rare in GB

that is my conclusion from the last thread. So take care.

Edited June 18, 2016 by TriumphV8

[AlanG]

Just taken mine for rebuild to Pete Drugen at Truck Transmissions at Blackburn. He is recommended by forum members. Mine was knocking accelerating/decelerating. Pete reckons it's showing signs of excessive backlash, possibly worn bearings maybe the same problem as yours. Due back end of next week.

Alan.

[ianc]

Pete Cox - he's being fettling gearboxes, overdrives and axles since the TR Register was founded in 1970, and he fitted a new crown wheel and pinion (plus bearings and seals etc.) in my TR4's rear axle over New Year.

As you will see from page 12 of the programme for the International Weekend, he will be running the first seminar on the Saturday.

Ian Cornish

[Julian Taylor_4995]

Many thanks for the prompt replies. My TR4a has 'form' when it comes to loosing teeth. In around 1988 I heard a click when pulling out from the car park at work. Five miles later and whilst negotiating a right hand bend at around forty MPH, the offside rear wheel locked with the inevitable result of a rapid and unexpected change of direction. It was as you described Ian - a tooth or two had come off the crown wheel and then jammed themselves into another part of the diff. Luckily the damage to the car was restricted to the mechanical bits due to some skilled driving from a guy in a Golf GTI on the other side of the road who managed to avoid me as I spun across the road. The rapid stop had sheared the key in the hub bearing and it hadn't done a great deal for the wire wheel either - I seem to remember there were broken spokes but maybe they were there already. My TR4a has overdrive so I think it should have a 3.7;1 ratio diff. Due to the fact that the car was my everyday transport I just had to grab what was available at the time so this sloppy axle is a 4.2:1. It is much quicker off the line but I run out of revs. Either way Ian's suggestion that I may be suffering from broken teeth has no doubt made me look a little pale. The axle will be out of the car very shortly for an inspection.

 

Naturally, if there are no broken bits I will pop the unit back in to get me to Peterborough and back and then i suppose I need to look at the back lash.

 

I will keep you posted

Julian Taylor

Edited June 19, 2016 by Julian Taylor_4995

[GT6M]

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