one more thing ..

[danthezookman89jx]

if i got a vibration through the drivetrain when im goin between about 50 to 80 and i got a oil leak at the front of my diff where the tailshaft goes in .. if that bearin and seal there is stuffed will that cause that vibration like that .. a mechanic wanted me to send my tailshaft to wollongong and get it balanced .. ?

[lay80n]

If your hubs are not locked in and your in 2wd, then oyur front drive train is not spinning or connected to anything, so theoretically should have no idput on vibration. What has been looked at before the mechanic decided you shaft needs balancing? Have uni's been checked, wheel balance, mounts etc??

Layto....

[Gwagensteve]

I think Dan means the input to the rear diff but I read it the same way as you the first time too.

Can you confirm Dan? If it is the front diff that you are talking about Layto os correct.

Dan, bear in mind that hte jackshaft unis are often forgotten and as they spin the fastest they are often a source of vibration.

I would start by putting fresh unis in the jackshaft and rear driveshaft and seeing how you go from there.

The seal being stuffed won't cause vibration, but if the seal leaking is associated with a stuffed bearing, then yes, maybe. The seal (and especailly the bearing) can't be changed without rebuilding the diff as the preload has to be reset. alhtough some have sucessfully just changed the seal, preload will be a guess and generally it won't last.

Steve.

[danthezookman89jx]

its comin from the back id say, but the fourby selector stick shakes the hardest and yea it does it when its in 2by .. i just looked at it .. does anybody elses sierra have about 3 or 4 mm play from side to side .. this would make it shake at speed hey ?not longways .. if i grab the tailshaft and push it she moves about 4 mm

[Eff]

I had the same problem with mine....between 50-80km/h and it only started when I put in a rear locker. Got my tailshaft balanced, new unis and he machined the yokes. He also said that the spines on the tail shaft were out which would have contributed to it. Now she runs smooth.
Eff

[Gwagensteve]

Where on the tailshaft is moving 4mm? If it's wobbling in the middle it will be slip yoke wear which will be down to poor maintenance/high kms.

This will cause plenty of vibration. Replacement driveshafts are around $150 from a wrecker, but you would want to know the kms that were on it because it could be just as bad and this won't normally be obvious until it is bolted in.

Steve.

[danthezookman89jx]

the car reckons its got 257 xxx on it but the motor was replaced .. i dunno if they did the shaft .. that would prob be enough k's to wear it hey lol .. yeah its right on the spline were it moves heaps

[sierrafreak]

go to drive line specialist they can rebuild the whole shaft for the price you would pay for a second hand one and have new uni's put in it.

Cost me $220 for a whole rebuild which was replace the two Y parts where the unis go in, the two pieces that bolt to diff and transfer, the two unis(with heavy duty ones), all that was left of mine was the straight part, the rest was all brand new.
That also included all the work i took the shaft to them they did it and gave it back that afternoon.

[Gwagensteve]

I might have missed something here, but if I am right, the "straight part" is the problem - the splined slip joint. This tends to be where the $$$ are.

Steve.