Bent Diff ????

[shymoggie]

Hi,

How on earth have I managed to get a car with a bent input shaft on the diff ?

Driving along and took the old girl up to 50 to see if she'd cope... I thought I was going to be launched !!!! The whole car took on a vibration that I can only liken to a Bomag road roller on vibrate setting !!!

When I got home I had a quick look underneath, at the dif end where the prop & diff are bolted you can see the diff shaft and the prop going in a sort of elliptical pattern, the only thing stopping the engine joining in is the universal joint at the front !!

I think it's always been like this, as I've never tried this sort of 'speed' before but has anyone any I idea how this has happend ?

Are the prop & back axle on a 2 door the same as on the four ?

[Willie]

I have recently had this problem with a supposedly 'expertly
rebuilt' diff unit. The pinion flange(which bolts to the prop shaft
flange) was badly bent!..This is a pretty solid lump of metal but
someone had managed to smash it out of true. Only cure was
a different pinion flange. Don't know if you have renewed the
diff or what but the usual cause of this sort of vibration is a
worn out universal joint, easily replaced, get one with a built
in grease Nipple not the 'sealed for life' type

[Kevin]

Jim if they are both from 1098cc cars or 948cc cars they will be identical including the ratio.

[rayofleamington]

If the diff shaft has severe run out then I dread to think what caused it, but a bust UJ may have been a culprit. When the propshaft runs out it can cause a lot of damage (I once had a bent gearbox output shaft).
Therefore when you change the axle (or diff) it is advisable not to re-use the prop even if it seems fine. The high loads may have damaged the UJ's so you want to replace those or the whole prop.

[rayofleamington]

and the prop and back axle should be the same if both the cars are 1098

[57traveller]

[Willie]

OOPs!

[Matt]

Even more useful than my normal remarks there '57...........

[shymoggie]

GREAT NEWS !!!!!!!

After all the panic, it was only the flange bent. So I've swapped the flange & propshaft (having greased it liberally)

..... boy does SHY move now ! 80mph !!!!! (On a private road, with no-one watching, wearing full race crash helmet )