I just replaced a drives side motor mount hoping it would solve a driveline vibration on acceleration. The vibration seemed to appear all at once, I suspect the center driveshaft support housing as it "clicks" when I shake the DS, it is a little loose but not sure if it is the source of the vibration. I guess it could also be the rear transmission bushing, or U joints Any ideas are appreciated.
Thanks
Dan

The problem was a frozen up rear u joint which was replaced, I also replaced a dry center DS bearing and support bushing for good measure.

All 3 joints got re-lubed.

All is well!

Thanks for all the suggestions, tail shaft bushing seemed fine.
Dan

Hi Dan,

I'm not recently practiced with auto transmission equipped driveline vibration.

Yet the FAQ can get discussion going.

https://www.brickboard.com/FAQ/700-900/Driveline.htm

If vibration appeared all at once, where before the driveline vibration start you encountered none, the loss of a wheel balancing weight or (unlikely) a drive shaft balancing weight.

I've found the smaller driver side motor mount can appear unfazed, yet it is split, as the engine lifts up on the driver side and pushes down on the passenger (oil filter) side when revving. All three may mounts require replacement?

If the center support bushing has shrunk, the drive shaft can wander around through the center support housing. Maybe low speed sensations. The shrunken bushing can shift in the hanger housing at low speeds (more torque) when accelerating and slowing down. More noticeable with a manual transmission.

Does the vibration start at speed and continue? Does it 'balance' at higher speeds.

Maybe more under-Volvo 240 wiggle time?

Hope that helps.

Dud.
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I did replace the drivers side blown out motor mount which didn't solve the vibration. The vibration is under acceleration and gets worse the harder you accelerate. If you take it easy and get put to speed there is no vibration or at least much less.

I just wiggled my 93 240 manual's DS and it has a similar clicking noise but no vibrations and the movement is similar. So my feeling now is it may not be the support bushing. There are not squeaks or squeals so the bearing must be ok. I guess I could remove the DS and check ujoints.

One thing I read was feel the E brake handle to see if the vibration is present in the handle which it is and that may mean the center support bushing is suspect.

Another thing might be a worn tail shaft bushing but that is something I have not experienced.
Thanks Kit

Dan

"Another thing might be a worn tail shaft bushing but that is something I have not experienced."

Sometime ago, I had a badly worn tail shaft bushing on my 90 244. As I remember, there was a vibration but I can't remember if it worsened upon hard acceleration.

Here are two other symptoms to help identify a worn tail shaft bushing:

1. Grab the front of the drive shaft near where the it bolts to the tranny. Shake it back and forth vigorously. The driveshaft should have minimal or no movement. If it moves much the tail shaft bushing is toast.
2. If the bushing is too loose then the rear tranny seal should also leak ATF. Look for ATF splashed around in the area near the rear of the tranny.

I suggest checking this out before going to the trouble of removing the DS to check the u-joints...:)

Thanks, I will check that I don't think it's leaking there but we will see.

I need to order those parts if it's an issue.

Dan

Just a suggestion. If you do end up needing the tailshaft bushing, it makes sense to replace the rear seal while you are in there regardless if it's leaking or not. Normally the rear seal starts to leak eventually as the bushing becomes more and more misshapen.

How many miles on the car? I had to do mine at about 200k which I think is pretty typical lifespan for that bushing in a slushbox 240.