PeachParts Mercedes-Benz Forum

PeachParts Mercedes-Benz Forum (http://www.peachparts.com/shopforum/)
-   Diesel Discussion (http://www.peachparts.com/shopforum/diesel-discussion/)
-   -   Rear end clunk during downshift? (http://www.peachparts.com/shopforum/diesel-discussion/390353-rear-end-clunk-during-downshift.html)

Father Of Giants 12-11-2017 04:05 PM

Rear end clunk during downshift?
 
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.

Diseasel300 12-11-2017 05:03 PM

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.

Father Of Giants 12-11-2017 10:03 PM

Alright, will do that tomorrow morning.

Father Of Giants 12-11-2017 10:10 PM

Alright, will do that tomorrow morning.

kuene 12-12-2017 04:47 PM

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

Father Of Giants 12-13-2017 06:43 PM

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

How do I fix it?

Diseasel300 12-13-2017 07:53 PM

Quote:

Originally Posted by Father Of Giants (Post 3772985)
How do I fix it?

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.

Father Of Giants 12-13-2017 09:03 PM

Quote:

Originally Posted by Diseasel300 (Post 3773002)
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.

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.

chasinthesun 12-13-2017 09:16 PM

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

Diseasel300 12-13-2017 09:18 PM

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.

chasinthesun 12-13-2017 09:37 PM

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

Father Of Giants 12-13-2017 10:42 PM

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

chasinthesun 12-14-2017 01:06 AM

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.

Diseasel300 12-14-2017 01:11 AM

Quote:

Originally Posted by Father Of Giants (Post 3773041)
Well that's a hard pill to swallow, thanks guys.

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.

swampmonkey 12-14-2017 09:28 AM

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


All times are GMT -4. The time now is 10:15 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website