Is it the transmission?
 

I'm just back from my nightly drive in my 280SEL W108, park my car on the gentle hill behind my house. The engine is off, the foot still on the brake, shifter in park.

When I let the brake pedal go, the car, which is parked downhill, goes clunk clunk clunk from the transmission and makes one hop forward with every clunk. I just had the transmission flushed and new filters installed.

What's causing this? It doesn't sound good at all.

The park thingie sounds stripped, maybe they can be adjusted I don't know. I hope your parking brake works til you can get it sorted out.

Tom W

Same problem mine has. I just made sure to fix the parking brake. It should be able to hold the car facing downhill, idling in drive, AND the car facing uphill, idling in reverse.

...and what do you think it is?
 

How can this be fixed?

Bent parking pawl from what other posters who've been through it have said in the past (psfred, I believe). You could disassemble the tranny, remove it and straighten it... but your honest best solution is to rely on the parking brake anyway. It's a parking brake, not an emergency brake on these for a reason :)

(Note: If I shift out of and then back into park, when it slips, it will stop slipping)

Less traumatic and much less expensive, it could be the bushings in the shift linkage. My 280C had to be put into park rather briskly or it would ratchet till it caught.

Michael

For sure inspect the bushings in the shift linkage and it's adjustment first. If you determine that the problem is internal, the park mechanism can be accessed without removing the trans.
In my opinion, the transmission in park is much safer than the parking brake.

I agree but would not spend too much $ to fix it myself if I had this problem.

Tom W

It's not a large task to repair the parking brake pawl and drum as it can be done without removing the trans. I dunno what the parts would cost.
My experience with Benz parking brakes is they will not hold on a steep hill.

Adjusting the parking brake: I'm pretty sure 108's have seperate shoes for park brakes, same as 116's independent of regular rear brakes. You dont just adjust the cable from underneath but look for screw-driver sized hole in back of PB drum for cam adjust that turns PB shoes closer to their drums. No dismantling required. Probly more DIY friendly as Tom suggested than messing with tranny linkages. If it was me thats what I'd do, or take it to skilled indie MB tech for pawl/drum repair.

yeah, but....
 

....I live on a steep hill. When I first got the car, the parking gear was it, because the parking break wouldn't work at all. Now it does - but not all that good. I think I want both.