Possible diff probelms HELP

After changing the VCU support bearings I have now discovered a drowning type of nosie coming from what sounds to be the rear of the car coupled with vibration, but this only happens on deseleration ? does anyone have any ideas what this could be ? please help kind of getting sick of the car now

IRD goosed? VCU & IRD probs are usually linked one goes and takes the other with it. Petrol & matches is ya best hope..,

The VCU is new ish ! and the IRD does whin abit but it comes from the back for sure and only on slowiing down ata speed of about 40 to 30 ish. is it possible i have possitioned the prop shalft to far back putting to much pressure on the rear diff ?

have you aligned the VCU bearings at EXACTLY 90 degrees to the centre line of the VCU?

As best I can !

I cannot feel any vibration through the hand brake or from that part of the undersdie of the car
Which was present before changing the bearings

if this has occurred only since changing the VCU support bearings then its a good bet that its them or something you've done thats causing the problem.

did you remove the props and VCU as one complete assembly? if not you may have damaged something.

Yeah took the whole thing off and worked on it on the bench, all UJs are ok and the CV joint is good. Kind of stumped really, I think I have done something wromg but there aint much to do wrong I have not touched much !

But thinking about it there was a small amount of vibration on the rear before but only very occationaly and when reducing from speeds of 75 down to 60 then it would disappear.

Only had the VCU support bearings come up as a prob when the car went to the garage for 2 weeks to have the head skimmed and new gasket. Should have just turned up the radio

you could have a worn inner cv joint or a damaged driveshaft.

But it is notablely worse since the job, The onlyt other thing i have just noticed in the dreaded hynes manual is the cups either side of the support bearings, The replacements wear of a different "shape " then the old ones the olds ones were placed cup side to the bearing on both sides which i replaced in the same manor but looking at the pictures they have them cup facing outwards does this make a difference !?"?

The only other thing i have noticed is that the bearing caps on the replacement were different to the orginals. The replacements were a slightly diferent shape. But i replced them in a likr for like manor cup facing the bearing, looking at the hyanes manual they have them cup facing outwards !!! would this make any difference??

did you get any diagrams with the replacements, if they are on the wrong way round they could be restricting the movement of the bearings.

nop no diagrams at all DOH ! I made sure that the bearings were free before re attaching the prop. I thought they were just dust covers or the like the only other thing i have done is drive it for 2 days in 2 wheel drive. I m confused, I ve re built 205 gti heads done gear box replacements all sorts but this car is a knightmere

suppose i ll just drive it till something falls off, which will not be to long ! lol.

What do doggy diffs some like ?

did you align the prop to where it was positioned before?
If all components are ok and oil levels in diffs ok then it could be just that something is out of line somewhere.

i'd put money on it that its the VCU support bearings.

marked the rear drive flange on the diff and fitted the rear prop in the same place, kinda forgot to mark the posstion of the front CV but that does not seem to be making any noise, the noise was there before but not as noticable. the noise I got from the support bearings was totally different they sounded very dry and gratty , this is a drown and vibration when slowing from speed. Any ideas on how to line the bearings and VCU up properly did it by eye before, cause the bearing casings and rubber parts are not all that true only the bearing them self is true,

heres another idea if i ve damaged the inner race on the bearing pressing it on would that make the same sort of noise?

shouldn't the bearings be true in their mounts, as its the support mounts that have adjustment