It always happens when the car down shifts and is slowing down, I was wondering what could it be?

Diff mount? Diff bushings? Motor mounts? Also you can feel the transmission clunk a bit to when at slow or awkward shifts

There is also a harsh and sudden clunk when going into reverse, it pretty violent too.

I think I have a compounding problems with mounts and bushings.

Also when push comes to shove, what tools do I need for the corresponding jobs? These clunks are driving me crazy.

__________________
1998 Ford Escort ZX2 5 speed - 279,000 miles My Daily

1992 Mercedes 300D 2.5 202,000 - Pure junk
2000 Mercedes E320 Black - 136,000 miles - Needs repair

Don't forget to grease the screw and threads on the spring compressor.

Slop in the driveline, probably the differential itself. Raise one of the rear wheels so it clears the ground, leave the tranny in park, grab the driveshaft and see if you have some rotational slop.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Alright, will do that tomorrow morning.

__________________
1998 Ford Escort ZX2 5 speed - 279,000 miles My Daily

1992 Mercedes 300D 2.5 202,000 - Pure junk
2000 Mercedes E320 Black - 136,000 miles - Needs repair

Don't forget to grease the screw and threads on the spring compressor.

Alright, will do that tomorrow morning.

__________________
1998 Ford Escort ZX2 5 speed - 279,000 miles My Daily

1992 Mercedes 300D 2.5 202,000 - Pure junk
2000 Mercedes E320 Black - 136,000 miles - Needs repair

Don't forget to grease the screw and threads on the spring compressor.

i had this issue and it turned out they knocked out the vacuum line to the tranny during a valve adjustment.

__________________
Andrew
Montclair, NJ
--------------
1982 300D Turbo
120k
Petrol Blue Green

Ok, it's slop in the driveline, the driveshaft has rotational play.

How do I fix it?

__________________
1998 Ford Escort ZX2 5 speed - 279,000 miles My Daily

1992 Mercedes 300D 2.5 202,000 - Pure junk
2000 Mercedes E320 Black - 136,000 miles - Needs repair

Don't forget to grease the screw and threads on the spring compressor.

Live with it until you can't bear it anymore, then buy or rebuild a differential. Making sure your vacuum system to the transmission modulator is *PERFECT* helps a lot.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

What parts are needed to rebuild it? Just curious.


Also, how can I replace all the vacuum lines? I don't know which lines.
How do I test the modulator? I have a vacuum gauge in hand.

__________________
1998 Ford Escort ZX2 5 speed - 279,000 miles My Daily

1992 Mercedes 300D 2.5 202,000 - Pure junk
2000 Mercedes E320 Black - 136,000 miles - Needs repair

Don't forget to grease the screw and threads on the spring compressor.

I think you just find if it holds a vacuum ,if it leaks then it needs replacing for the modulator .The rearends are common enough that you might find a good used one at a yard ,never had a rebuilt .I imagine if its coming apart ,new parts added ,going back with new mounting bushings by a mechanic ,$700. and a sandwich

Tee into the black line going to the transmission modulator and go for a drive. At idle and not moving, you should have somewhere around 12-15" of vacuum going to the modulator. Under strong acceleration it should drop to ~5" and at WOT it should drop to 0". If you have good vacuum going to the modulator, there's not a lot you can do but live with it. Rebuilding a differential is not for the faint of heart, it would be a lot easier to source a replacement or have yours rebuilt professionally, especially if the gears are worn.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Heres a good link to possible answer some differential issues.differentials, gear-ratios and compatibility | Mercedes-Benz turbo

Well that's a hard pill to swallow, thanks guys.

__________________
1998 Ford Escort ZX2 5 speed - 279,000 miles My Daily

1992 Mercedes 300D 2.5 202,000 - Pure junk
2000 Mercedes E320 Black - 136,000 miles - Needs repair

Don't forget to grease the screw and threads on the spring compressor.

We get alot of miles on the parts that the factory installed orig., They can still give some miles if babied.The noise of old age, we also will become much like our cars ,old farts.

So long as the rear end isn't growling or vibrating, you still have a lot of life left in it. Keep up with the oil changes and let it ride.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

hmm, the clunking might be a lot of different things.
axleshafts, driveshaft or differential, on one occasion a gearbox.

on a w114 with sort of the same issue as you describe it was the differential,
Montefeller’s w114 280CE – 3.69 to 3.07 differential swap | Mercedes-Benz turbo

the thread has video of both diff mounted and play found without dissembling anything, aswell as the second video of what was the issue. Seen that on multiple differentials.

https://www.youtube.com/watch?v=5W3629vkI5k

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daily: w123 om602turbo 5speed 200whp, w115 240d 3.07 differential
mbturbo.com turbo diesels+gassers in oldtimers/classics