2003 s500 vibration
 

I am working on a 2003 s500 with 99000 miles on it. I don't know the history of the car as it came from auction. the vehicle idles smooth and accels smoothly up to 3,000 rpm. either in park/neutral or on the road. but, at approx 3200 rpm there is a shudder type vibration felt throughout the car. it seems harmonic in nature and can come and go. Again, it is there both in park/neutral and on the road. When in park, and held at 3200 rpm, the vibration can be changed, almost eliminated for a few seconds by pressing the c/s switch on the console. Motor mounts, drive shaft joints, etc all look ok. No obvious signs of recent repairs performed

My 500E has a similar problem and it has me and my mechanic stumped. He thinks the drive shaft is out of balance. I suspect a tire problem. I'll post if we figure it out. (Since our cars are so far apart in years though my answer may not be much help.)

vibration
 

the vibration feels like an out of balance issue like a harmonic balancer. The baffler is that it actually changes feel while in neutral and the c/s switch is hit, which controls trans shift points, etc. Feels like someone is shorting out cylinders to do a cylinder balance.

Try a new transmission mount. I've seen similar things like this before. Not a real risky proposition since the trans mount isn't too pricey.

have your mechanic look at drive shaft alignment//he may need to pull the driveshaft to chk u joints//there wont be slack in u joint but something that feels like stiffness in one spot of u joint..if thats the case then make sure
drive shaft is realigned befire installing new drive shaft...good luck

I appreciate the input on the driveshaft alignment, but I ruled that out because te vib can be felt in prk/neutral and can change with activation of c/s switch. I am guessing that it is caused inside transmission, however it drives and shifts fine except for the vib.

The trans mount is a good idea...

You might find the problem if a "good" technician can SLIGHTLY jack-up the engine and/or the trans & then see if the vibration changes or GOES away.

OF course use a block of wood & don't get crazy & raise the engine too far.