1971 3.5 diff clunk

Howdy all

I have myself a 1971 108 3.5 which has been going really well. However over the last few weeks I have developed a clunking noise around the righ hand rear wheel. This noise occurs mainly when my auto transmission changes down.

There is no noise at all when changing up under power it just seems to occur when I am changing down. In fact the transmission is very smooth changing up.

Going from park into drive and/or reverse whilst stationary also seems to create a fair clunk.

Any ideas???? Have a got a stuffed diff?? Do these 108 3.5 have a standard diff??

I have also notice that my diff seems to be leaking oil somewhere. I have not identified which area yet. Could it just be low on fluid? (hopeful)

Any ideas would be appreciated.

John King
Tasmania
Australia

[toms]

I had this problem in the past on my 71 280sl. In my case, the idle throttle switch was not working. I can't tell you exactly what happens when this switch activates, but it triggers a pressure switch on the transmission that, when activated, adjusts the transmission fluid pressure and prevents the hard downshift at stops. The idle throttle switch is on the venturi intake manifold.

[Tomguy]

I didn't know they made 108's with the 3.5, thought it was only on the cabriolets!
I assume you've checked your fluid level in the rear end? Is there any play in your u-joint?

Originally posted by Tomguy
I didn't know they made 108's with the 3.5, thought it was only on the cabriolets!
I assume you've checked your fluid level in the rear end? Is there any play in your u-joint?

Yeah, these were also produced as W108 280SE 3.5 sedan. We have these in Oz(Australia), and also in New Zealand too. The 4.5's were mainly for the North American market and as such are pretty rare down under.

Cheers,
Mick