Possible Diff or Gearbox problem?

[apb]

Hello to All. I have a 1989 250TD Manual. I have only owned it for a few weeks. The problem i have is between 20 to 40MPH, there is a very bad low vibration which resonates through the whole car. It's worse on moderate acceleration or decceleration. There are no shakes or wobbles through wheel or car and above 40 it is fine all the way up to motorway speeds. I have changed the engine mounts and checked gearbox mounts, prop rubbers, u/joint, fluids, wheel bearings and also looked everywhere for metal to metal contact underneath the car. It sounds and feels like the diff or gearbox is the problem but i thought that if that was the case, it would be there all the time at any speed! It's baffling me! Any suggestions are greatly appreciated. Thanks.

 

[television]

Did you check or change the center bearing on the prop

 

[roofless]

first thing is as per television the prop & the only other thing i can think of is badly worn wishbone bushes or broken spring can give vibration

 

[apb]

Hi, thanks for the reply. I have looked at the center bearing rubber and it does not look deteriorated. If i push or pull on the prop at this point it moves about 10 to 15mm either way. Is this normal? Also, what is the best way to check the bearing? Do you jack up the rear and run the car in gear? Or do i have to take the prop apart? Regards, Alan.

 

[apb]

Hi again! I forgot to ask you guys that if the diff or gearbox was the problem would the noise/vibration be there all the time?

 

[apb]

Hi, i am going to replace the center bearing and carrier when i get the chance but i thought i would mention that in the mornings the noise and feel is not as bad! It seems to get worse the further you drive so does this suggest that it is definately rubber/bearing related? The parts must be softening up when they get warm or hot in regards to the rubber so there is more movement. When you order a new center bearing does it come pressed into the rubber part or are they separate parts? Thanks again!

 

[television]

Have a read through this.

http://forums.mercedesclub.org.uk/showthread.php?t=46449

 

[apb]

Hello, before i do the job on the center bearing i should just mention that the noise/vibration goes away completely when freewheeling. Does this suggest that it is not propshaft related? Maybe gearbox? I hope not! I just want to make sure before spending lots of time and money on such an old car.

 

[Bolide]

Prop centre bearing, prop doughnuts (flexi couplings), particularly the front one, worn diff bushes, ovalised diff input oil seal & bearing, bent or out-of-balance prop

Nick Froome
www.w124.co.uk

 

[apb]

Hi Bolide, thanks for the info. The center bearing is the first thing to look at. The front flexi is new! The rear could do with replacing. The engine mounts are 1 week old. The gearbox mount looks OK but when backing out of the drive there is a noticeable shake in the driveline, but not in forward. Diff bushes are probably original, but i have read on here that they are a pain to do! I thought if it was to do with propshaft it would still happen when frewheeling! Is this not the case? I know i have spent a week or so blabbing on about this on here but i just want to get the advice from people who may have gone through this before. Yours and many others help on here is helping keep these old but fantastic cars(well sometimes) on the road instead of in the scrapyard! Keep it up! It's a great service you all do! Regards, Alan.