When I uncoupled the propshaft from the diff, some oil ran out from between the flanges (RED).
I presume that the diff input shaft seal is at fault, but what I don't understand is how the oil worked it's way through to the securing bolt (GREEN) and why it didn't just leak from the outside of the diff instead (BLUE)?



The vehicle has done 140,000 miles and the oil leak must have been there a while as the underside is coated with black gunge so is the top of the A-Frame as you can see.

If it is the diff seal I need, can anyone recommend an aftermarket item?

Thanks - Mark

 

It is probably oil that has worked its way through clearances in the splines. Diff seal would, as you have rightly concluded, be the area marked with the blue arrow.

How is your A-frame?

 

Diff oil leak? Looks like a diff oil dribble, now this is a diff oil leak!

 

Thanks Sheddist.
So I don't need to take any remedial action for this, other than drain the diff and fill it up with fresh oil?

BTW the A-Frame appears good - I haven't found any holes yet but will not be stripping it down until I have sorted the rear end rot (one job at a time).

 

You could mark the pinion nut for position, remove it and apply a silicone sealant to the flange/shaft/nut. Re-install the nut to original position and re-stake it to the pinion shaft.

Reusing the original nut (marked to ensure original location) saves trying to setup the pre-load on the pinion shaft bearings. If it was correct before, it should be correct now.

There was a TSB for the X-Type propshaft output flange that leaked oil and the solution was to apply sealant to the flange/shaft/nut area.

bob gauff