Diff input bearing symptoms

Hello der fellas,

Had a few problems a couple of weeks ago with prop shaft uj's, changed all suspect ones and still getting a knocking from the rear axle when engine is low revved in 3rd and 4th gears. when rear prop is taken off and running in difflock, she is the smoothest mofo ever, however when rear prop is connected problem recurrs.

had both rear wheels off the floor and noticed that i could move one wheel almost a quarter of a turn before the opposite wheel moved.

the only thing i can think of now is input bearings on the diff. all hub bearings are good.

its a 300tdi 90 boys, please help!

Regards,

Ash

A worn input bearing will rumble, but won't cause excessive free-play.
Your symptoms sound more like a worn pinion / crownwheel or half shaft / drive member splines.

best way forward to just pull the thing off and take it to bits to see whats worn?

spotted your photo guide already....

Pull the half shafts and check the splines on them and the drive members first.
Then the diff if they look OK.

Funnily enough, I have just had a similar problem. Lot of movement on the input coupling on the rear diff. I assumed this was the input bearings. Got the little spigot thing off the input coupling eventually and found that the nut holding the coupling had worked loose. By this time, I had applied so much heat to the bloody thing I will have to replace the seal anyway.
Doesn't sound quite like your problem but if you can get the spigot off without removing the diff it might be an easy fix.

A frame ball joint !!!
Get a prybar on that sucker and see if theres any play in it befor ripping your axle apart