Replacement VCU - vibration, then noise

Had VCU and bearings replaced a few weeks ago, next door neighbour is a mechanic with reputable garage in town so gave him the job to do. I should have known better when he said 'it's been a while since I've done one of these, but we have done one before' :doh:.

Anyway, got car back and took it out for a run, all ok up to about 45-50mph where a noticeable vibration from the prop could be felt through the car, 60mph and above the vibration hadn't completely gone but was was much less noticeable. He must have known about it because he's never charged me for the work, I didn't consider it a big problem so I never challenged him about it.

Went out for a run of about 50 miles last weekend and noticed on the way home that the vibration was definitely getting better and easing off. Parked car up until I needed it again a couple of days later, as soon as I pulled away up the road there was a whining/grinding noise which increased/decreased in pitch as the car accelerated/braked, my best guess is it's the VCU bearings. I'm assuming that the vibration has got less because the VCU bearings have worn out and cooked on the previous journey?

Has the VCU been checked? Does it get hot after a few miles driving?
Read up on here about VCU and IRD failure, they are usually linked!

VCU and bearings were brand new from Island 4x4 so wouldn't expect there to be any problems. Is there some procedure that should be followed when replacing VCU/bearings to ensure that they are balanced or aligned properly?

Haynes book simply says they must be lined up at 90 degrees to the prop/VCU which should be straight. Are they good bearings or cheapo ones, Bell Engineering advised me to steer clear of cheap ones with crappy bearings. They should have worked 'out of the box' though....

first off jack one rear wheel off ground and turn wheel with biggish bar and socket to make sure viscous actually turns slowly and smoothly with some effort,new parts can often be faulty ,there isnt anything complicated about fitting v/c,check yokes on prop are aligned in same plane people worry about making sure prop goes back in same place on ird and diff flanges which makes no difference at all but arent worried about the yokes in prop that do matter

jamesmartin said:

first off jack one rear wheel off ground and turn wheel with biggish bar and socket to make sure viscous actually turns slowly and smoothly with some effort,new parts can often be faulty ,there isnt anything complicated about fitting v/c,check yokes on prop are aligned in same plane people worry about making sure prop goes back in same place on ird and diff flanges which makes no difference at all but arent worried about the yokes in prop that do matter

Click to expand...

since the yokes are welded to the shafts there's nothing to worry about there either......

of course they are welded to shaft,but i cant remember whether it is possible to get alignment wrong either side of v/c,which would have had to be removed for v/c fitting,i take it your one that marks front prop cv to ird before removal

I had brand new named bearings - not cheap ones fitted with a brand new VCU and they were groaning/whining straight from the box. Garage changed them after a few words for Landrover ones and they were quiet as a mouse...whining has come back again now a little bit but nowhere near as bad...had some very very very dusty trips this month so wondering if the fine sand has got into the prop bearings? I know they are sealed but this dust was oooober fine!?

jamesmartin said:

of course they are welded to shaft,but i cant remember whether it is possible to get alignment wrong either side of v/c,which would have had to be removed for v/c fitting,i take it your one that marks front prop cv to ird before removal

Click to expand...

then you take it wrong, no advantage in markings at pinions or VC