I have NEW driveshafts on the car as stated so it's not the cv-joints and i tried other wheels and tires aswell.

@Maxbumpo: Im going to try and do that while another person drives the car, good tip!

Pretty sure its your rear diff stalling out. What gear ratio is back there?

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http://superturbodiesel.com/images/sig.04.10.jpg
1995 E420 Schwarz
1995 E300 Weiss
#1987 300D Sturmmachine
#1991 300D Nearly Perfect
#1994 E320 Cabriolet
#1995 E320 Touring
#1985 300D Sedan
OBK #42

3:46 and im looking for one in better shape then mine but it's really hard to track one down, im finding multiple ones but everyone of them have much more play then mine.
Every car with a worn diff i've been in have had a whining noise tho, this is a very very deep humming noise.

I mean the description matches a stalling diff, 3,4,5th gear at low speeds..... I know at 35mph in 5th my car is unhappy. But with a 3.46 I would think this would not be a problem.

__________________
http://superturbodiesel.com/images/sig.04.10.jpg
1995 E420 Schwarz
1995 E300 Weiss
#1987 300D Sturmmachine
#1991 300D Nearly Perfect
#1994 E320 Cabriolet
#1995 E320 Touring
#1985 300D Sedan
OBK #42

Im going to try and replace it, just have to find another diff but almost every w123 in sweden has 800k+ miles on them so it's very hard finding one in good condition.

Would you consider buying one from the U.S.? I'm not sure what shipping would run, but good diffs seem to be pretty plentiful here. Member VSTech probably has a couple laying around.

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Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 400,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 22,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.

You should be good with a 2.67 or 2.88 diff. Can probably find a worn LSD even over here.

__________________
http://superturbodiesel.com/images/sig.04.10.jpg
1995 E420 Schwarz
1995 E300 Weiss
#1987 300D Sturmmachine
#1991 300D Nearly Perfect
#1994 E320 Cabriolet
#1995 E320 Touring
#1985 300D Sedan
OBK #42

Im keeping my eyes open at all times and i'll report back if i find one.

Keep guessing what's wrong with the car btw, everything is appreciated!

It sounds like you have a problem with one of the rear sub-frame mounts. I have had a rock jam in one & cause a noise like that.

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Grumpy Old Diesel Owners Club group

I no longer question authority, I annoy authority. More effect, less effort....

1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
Other toys ~J.D.,Cat & GM ~ mainly earth moving

I have new subframe mounts so that's not the issue.

Get an acoustic guitar mic/ walkman / earphone with help of a passenger to localize source.
There's are seams in trunk where it meets rear fenders which are glued in. Check that it is not separated.

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked