1997 E320 Vibration
 

Hi all,

I am hoping you can help me. My 1997 E320 has a vibration which seems to be coming from the rear of the car between speeds of 35-45 mph. If I speed up as soon as it starts the vibration goes away. My initial thought is drive train. It seems more noticable when there are several people in the car. Does this sound like a U-joint? Or flex disc problem? I can I tell?

Thanks,

If you down shift into a lower gear manually is the vibration still there?

IF not then possibly the torque converter lock-up is happening at that speed!

MB,

If I shift it over to 4th it will do it also but I'll have to slow down just a bit. The vibration isn't too bad, in fact if you go from 0-60 It will never happen. It only occurs when driving around 35-40 mph really. If you speed up or let off the accelorator when it occurs the vibration immediately goes away. It's almost like a sweet spot on the accelerator. I checked the pressure in all of the tires yesterday and one of the rear wheels was low about 10pds after filling it up the vibration seems a little less noticable. However I've had many tires out of balance in my day and this just doesn't feel like one...I could be wrong I guess. Any thoughts?

It seems as if this is occuring mostly at 1500 RPMS no matter what gear. Could this possibly be the center bearing?

Anybody??

I had driveshaft-related vibrations. They were rather speed-related than RPM-related. In your latter post you say it happens at 1500RPMs. Is this also true while standing and reving up in neutral? Is the noise rather rattling or humming?
Motor mounts, transmission mounts, cat heatshield, cat inside, differential mounts may be other components to be checked besides the ones that have been mentioned already.
Good luck, Bruno

If the vibration is related to engine RPM and not vehicle speed, then it's unlikely to be the center driveshaft bearing. The driveshaft turns at a specific RPM for any given road speed, regardless of which gear the transmission is currently in.

Given that your problem is RPM specific, I'd look toward motor and/or transmission mounts. Collapsed motor mounts are relatively easy to diagnose.

- JimY

Thanks guys!

I not only hear the vibration but I also feel it very well. In fact its also evident to passengers. It feels like its coming from the rear of the car. I know these vibrations aren't always as they seem though. I checked out the engine mounts before I bought the vehicle. They look fine (not flat), How do I diagnose a bad transmission mount? Would they be flat as well?

Thanks

I do notice a very slight shimmy at idol. Just for reassurance what does a bad motor mount look like. I guess the only thing that is throughing me off is that I know my 1990 300E needs motor mounts and it doesn't do anything like the 97...but then again it is a completely different bird.

Thanks again,

A shimmy at idol sounds like a motor mount to me.

One way to check is to have someone press on the brake and give the motor a little gas: once with the transmission in drive, and a second time with the transmission in reverse.

If one (or both) of the motor mounts is bad, you will see the engine sort of jump up, either in the front, or the rear, depending on what gear your transmission is in.

Believe me, you will know it when you see it.

Further, don't rule out either transmission mounts or differential mounts.

Hey Paul,

Thanks I'll try that when I get home this afternoon!

How is everything?

Everything's great.

We bought a 2000 Volvo S70 for the wife. It's a pretty nice car. The seats are supremely comfortable, but the car is a little underpowered.

Good to hear !

S70 seems to be great cars. There are several here at the office who have those as company cars and love them!

I'm feeling pretty good about my purchase of the 97. It has 147,000 on the clock. The previous owner took extremely good care of it and they truely are Highway miles. He even had the "sealed for life" transmission serviced at 60K and 120K. It has a couple of dings on the passenger side but other than that it's runs, drives and looks great! Considering I got him down to $8,000 for it I don't think I can complain too much about the door dings.

P.S I had the car PPI'd and they found nothing...wonder if they missed the engine or trans mount.

Paul,

I had a chance to try the test you mentioned. I did notice a very slight hop in the motor when shifting to reverse and also into drive. I also notice this weekend that the vibration only occurs when the car is at and very near normal operating temp... Strange !! Does this still sound like an engine mount? :)

It makes no sense to me why it would occur only at or near operating temp.

I don't know if it is a motor mount or not.