Transmission whine

[Jabba]

My 90 has developed a deep whine above 25-30 mph while under power (not on engine breaking). If I want to check if it is the diffs, can I just remove the propshaft from each one or do I need to remove the half shafts too?

Cheers,
Dave

[davew]

You should be able to tell just by removing the propshaft although removing half shafts will isolate it completely.

If you remove the rear propshaft, check that the hand brake drum has it's securing screws and/or put the propshaft nuts back on with spacers to make sure the drum can't come off.

[Jabba]

Front propshaft out. Went for a drive and the noise is gone. The front diff is leaking from the pinion flange (again - I'm sure I've already replaced the seal) so I'll check and fill the oil but I'm thinking I'll be replacing the diff.

Any suggestions whether it is better to replace with a recon unit or to try and find a good second hand one?

It's a 10 spline diff in case any one has a good one lying around....

[davew]

If it can wait, I should have two spare 10 spline diffs available in a few weeks, they're in Pam's motor at the moment. Just waiting for the ARBs that were in mine to come back from Crown Diffs.

If you want to go down the re-con route I can recommend Crown Differentials, they do a really good job but can be a bit spendy compared to just getting a second hand diff. 10 spline diffs go for very little cash second hand.

[Jabba]

Hi Dave,

Sent you a text. It can certainly wait a bit for the diff. If yours are in good fettle then I'd be interested.

Cheers,
Dave

[Jabba]

If I'm going to leave the front diff disconnected for the moment, can I remove the outer drive shafts without having to remove the CV joints and inner shafts as well?

[davew]

I wouldn't, not for any distance anyway.

Although in theory the half shafts and CV's would be "dead" the vibration of the axle with nothing to restrict the end float of the half shaft and CV could lead to all sorts of problems. In the worst case the CV or the half shaft could block the swivel housing, restricting your steering. (You hit a pothole, CV drops off the end of the half shaft, half shaft slides into the swivel housing and jams it).

It'd probably be OK but the consequences of it going wrong are too severe to risk it in my view.

[Jabba]

That's what I thought might be the case. Guess I'll just leave them in then as I can't be arsed to remove the inner shaft and CV as well!

[Matthews]

The outer halfshafts are part of the CV on 90's , it's only RR's and some of the discos with FF cv's that the outer shafts are a separate entitiy.
Matthew

[Jabba]

Having checked the oil in the diff, it was full of mucky grey emulsion. And I do mean FULL! Probably explains why it was leaking from the pinion seal.

I drained the oil, flushed it with some paraffin to try and clean out the gunge and refilled with clean EP90.

The pinion flange/input flange seems to have some movement in it, both in and out (i.e. front to back) and rotational.
Is it possible to shim.adjust the movement/backlash without stripping the dif or is that just likely to wreck the gears?

Thanks.

[nicks90]

its knackered i;m afraid.
your front pinion bearing is/has/about to collapse. Once movement in and out is noticeable it usually means new diff time - as the meshing of the gears will have changed and 'worn' the pinion and crown wheel mating surfaces,
even if it hasnt actually knackered it and you are able to replace the bearing, the chances of it running quiet again are very slim.

[Jabba]

Thought as much. Guess I'll be replacing it then.

Thanks.