W124 intermittent vibration at higher speed

[krimat2005]

Hi all, so i do get as in the title above 65mph, you can fill it through chassis and steering wheel. before anyone say it it's not anything suspension/steering related as it has been rebuild, it's not wheel inbalance as I just changed to diffrent wheels (balanced) and same with both set ups. I was searching the forum and it come up that it might be the transmission mount especially when the engine mounts have been done as by doing so you misalligning whole drivetrain (gearbox-propshaft-diff). can someone confirm this theory? there are some pics that might help
also looks like rear seal on Autobox is leaking is this easy to do?

 

[kth286]

In my experience it will be the geometry out.

It may have been rebuilt, BUT have you had a 4 wheel alignment done.

The rear alignment is always done first to ensure car is tracking straight verses the chassis centre line, and not crabbing up the road.

The front is then aligned to the centre line.

 

[krimat2005]

done on HUNTER's equipment, all good.

 

[Sp!ke]

Is the steering damper sound?

 

[krimat2005]

yep, checked that yesterday and it's nice and tight, MB item

 

[grober]

Could be the flexible mount on the split propshaft centre bearing or perhaps one of the flexible couplings

 

[flango]

Seen this before usually engine and transmission mounts, theres a post on here somewhere for very similar was it by TrapperJohn maybe

 

[krimat2005]

well engine mount were done about 25k ago with MB items but not the tranny mount.
thanks all, any obvious thoughts from pics?

 

[bing]

How many miles on the tranny mount ?

 

[WDB124066]

Is it a wobble or hummmmm type vibration?

 

[krimat2005]

well car is currently on 226k (belived to be true as paperwork confirms), I never done the tranny mount so prop never done.
WDB124066 dont really know how to describe it, when you go past 60mph it's start to shake/ vibrate the whole car, can feel on steering and through seat. and most mysterious about it is only intermittent, it's there now, 5 sec later all good??

 

[BillyW124]

what Grober says, check the Centre propshaft mount..

 

[rorf]

Judging by those photos the flex disc and transmission mount look shot. I would imagine the engine mounts are gone too.

 

[krimat2005]

Judging by those photos the flex disc and transmission mount look shot. I would imagine the engine mounts are gone too.

I would imagine reading from the start, no offence but i stated twice and now for the third time engine mounts have been done about 25k ago with genuine MB items.
also i can agree that tranny mount is shot but flex disc? looks like new to me, well 25k again MB.

 

[krimat2005]

hi all again, i had a bit of time off work so managed do to little bit, changed the centre bearing as it had a bit of play and tranny mount and now i'm getting vibration only on overrun above 65-70mph once below that speed there is nothing, been driving in germany recently and did some fast runs 100mph+ (for 300D 113bhp) and all is good as long as i'm on the throttle, let it go above 70mph and you get vibrations? what is this? I'm getting sick of it as I like my car perfect and it's not, why??

 

[hondo]

Iv got an intermittent vibration on my w202 Iv changed engine/g-box mounts, centre bearing and Flexi discs its still same, the thing is somedays it's worse than others and only occurs between 60-75mph which is typical of wheels requiring balanced or flat spot on tyre so Iv done that too even changed wheels and tyres but no difference my hunch is prop has somehow became unbalanced or c/v joint is playing up although when I had it off I could not feel any play or roughness on it ,I know how you feel it's the only thing about my car that is not as it should be and it drives me mad eventually I'll get it or die trying its just that you can't keep throwing money at a car and replacing parts it doesn't even need

 

[John Jones Jr]

hi all again, i had a bit of time off work so managed do to little bit, changed the centre bearing as it had a bit of play and tranny mount and now i'm getting vibration only on overrun above 65-70mph once below that speed there is nothing, been driving in germany recently and did some fast runs 100mph+ (for 300D 113bhp) and all is good as long as i'm on the throttle, let it go above 70mph and you get vibrations? what is this? I'm getting sick of it as I like my car perfect and it's not, why??

Rear subframe issue? For instance if the bushes have never been replaced it would be fair to say they've seen better days, or maybe some flex in the subframe due to a crack?

 

[WDB124066]

Spline wear in propshaft...?

If you hold the propshfaft and push it hard up and down you may get an indication of wear....

 

[grober]

Well vibrations on the overun above 65-70 point to 2 things. First its probably rotational speed related and if it occurs on the overrun its when the wheels are driving the driveshafts/differential/ propshaft /u/j's -----You did mark the 2 propshaft halves when you renewed the centre bearing and its mount I hope?? [ the entire propshaft is balanced as a unit and must be reassembled as it was before splitting. ] and You replaced the mounting exactly where it was before? What are the differential flexible mounts like- they can get soft with oil??

 

[krimat2005]

i was thinking about driveshafts but how do i check them is it poss to do when they in the car? propshaft/centre bearing was reassembled in the same position but I've read somewhere that when you remove gearbox mount and centre bearing then you have to realign them: don't tighten the bolts(for gearbox mount and bearing) fully but roll the car back and forward and then tighten. I haven't done this as didn't have access to a pit, so thats next thing on to-do list. Diff mounts were done about 25k ago but diff is leaking slightly so might put that on the list as well. thanks all