Anything and everything Vitesse.

Rear axle, brakes, wheels and tyres.

Hi all,

I have a question for the diff experts....

I have just fitted a new diff to my Vitesse ,as the old one was whining more than me. It has been built with a new crown wheel and pinion, as specified and purchased from a long standing well known Triumph dealer.

Having fitted it back onto the car today and filled it with oil I discovered that when I try to turn the propshaft flange there is a very distinct ' high spot', whilst rotating it thro' 360 degrees. When I say 'high spot' I mean I can barely turn it by hand. I appreciate that with new innards the flanges are going to be tight to turn - but surely this not normal ?

I have unscrewed the spring mounting studs to eliminate the possibility of one going in too deep and fouling the innards, but its still the same.
I cannot come up with a rational explanation at the moment and as its Bank Holiday cannot even contact the supplier.

I really don't want to have to take it out again, as you know what a pig of a job it is, unless absolutely necessary !

Although a new diff may be a little stiff, I can think of no reasons why there should be any tight spots. Although it might run itself in pretty quickly, it might also wreck itself equally quickly. If you have identified a problem (and publicly on this board!) and still used the diff, you might have difficulties with warranty or exchange for reconditioning, as well as ruining one of a limited number of new crown wheels.
SO, frustrating though it undoubtedly is, I would not use the diff until I had discussed the matter with the supplier. I would have expected any decent diff builder to thoroughly check a diff after assembly, and he might be able to explain a tight spot, (in which case I would be interested to hear the explanation!!) or at least reassure you that it is ok to use.

Hi Chris,

Thanks for your thoughts. As I said, I can come up with no rational explanation either, other than a distorted/ faulty crownwheel. Like you I would assume that the builder would at least rotate the prop flange thro' a full 360 degrees a couple of times to check all is well. Needless to say reassembly of the car's rear suspension has come to an abrubt halt whilst the problem is investigated. A call will be going in to the supplier first thing.

Hi all.

In case in anyone's interested I can now reveal the problem with my 'jamming' diff. As I had specified a drain plug to be fitted the supplier had duly done so. I was told that this was achieved by using an early Herald 1200 rear case ,which was already fitted with one from new, and having had the 1/4 shaft bearing holes enlarged to take Vitesse bearings.

When I opened the case - having got permission to do so from the supplier - I found that the edge of the crown wheel / carrier had been rubbing on the inside of the case.

I spoke to the supplier,who was very apologetic, and he explained that he had never encountered this problem before - probably because I was the only person to request a drain plug to be included in the build ! Needless to say it had all checked out ok during building, as the rear case was only fitted last thing.

Comparing the two inner faces of the rear case where it curves around the c/w there appears to be a very subtle difference in the two castings.

Anyway I have been supplied with a replacement normal Vitesse case and all is well.

Yes, I'm interested at least-interesting to know how these things work out (even if it does take a while!) as it all adds to our collective knowledge. That's what we're all here for isn't it?!!

If it was an unmachined part of the crownwheel carrier, or a bolt head touching the rear case, that could cause a tight spot. If a MACHINED face of the crown wheel or carrier was catching on the rear case, that suggests something not running quite true. With the preloads on both pinion and diff carrier bearings, everything inside the diff should run absolutely true.

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