Need/cost for differential rebuild?

I have a '74 450SEL with about 250,000

Anyway, the differential is original. I'm getting these symptoms:

1. There is a "clunk" from the rear-end when accelerating, and another "clunk" when you let off the gas.
2. The car rolls about 10 inches or so when it's stopped and put into park.
3. There is a 3-second delay between putting the car in reverse, and it actually backing up.

I'm guessing the differential is the culprit, based on the other posts I've researched ... maybe it needs a rebuild? Does this sound about right?

And if it is the differential, what is a resonable price to have the work done? ... I have average mechanical skills, but from what I've read, differential work often needs a pro.

Thanks, and cheers

[stevebfl]

More likely a driveshaft coupling or drive axle c/v joint play. Large amounts of differential play are usually accompanied by other noise.

Thanks Steve

I was going to go under the car today. What should I be looking for that would indicate excessive play in the joints or coupling?

What can I do troubleshoot the differential as a possible problem?

Thanks again

[MikeTangas]

Agree with Steve, not a rear end problem. Likely worn flex disks or differential mounts causing the clunk.

Rolling about 1-6-10 inches when placed in park is normal. That is the distance it takes the parking pawl to engage the notch in the transmission. Not sure when they beefed up the pawl, it's real beefy on the 126, but on the 108 I always, always, always use the hand brake, because it doesn't always engage.

The delay in engaging reverse has nothing to do with the differential, that's in the tranny. Most folks I know just live with it. So you have to wait a couple seconds, no biggie.