Balance problems with Automatic transmission
 

Hi there.
I'm new in this forum, and I hope that somebody might have an answer to my problem. I have a w108 280SE, and I have changed my transmission from manual to automatic. After i changed it, there sem to be a problem with the engine/transmission balance, so everything is shaking. Have anyone got an idea what causes the problem?? :confused: :confused:

Kind regards

We really need more info.
OEM parts or did you make things up.
OEM from were? another W108
New or old tranny and engine mounts?
Drive shaft. was it sortened? Was it rebalanced if cut?
when removing the drive shaft did you put it back in the same orientaiton that it came out in.
I know in the W123 there are marks to make sure the drive shaft is installed in the correct orientation or it will vibrate. did you insure this?
Pressure plate/clutch assembly OEM or rigged? could be out of alignment. Was it installed properly with an alignment shaft?

We need more info.
Give us details of the job and your abilities. Have you worked on mercedes before? or are you new to them?

Dave

You must match the balance on the flywheel to the old one, or disassemble the engine and have the crank, flywheel, and front balancer balanced together, drilling the flywheel.

It's also possible that you have the flywheel out of place -- one bolt is offset to "key" the flywheel, but if you screw the bolts in to the "neck" when installing, you can get it on in any position due to the small diameter of the stretch bolts.

Peter

Thanks for the answers. I feared the answers I got, especially the last one. I've just finished a nut and bolt restoration of my car, and are not really keen on disassembling the engine again. And yes, I've been working with classic mercedes for 6-7 years, but never tried to switch between different transmission types. Well, not with the old models. I've done it with the w123, and have never experienced problems like the ones I'm facing now. But I think I got a little more clever. Thanks for the help, and I'm sorry if my english is not perfect, but it's not my primary language.

Kind regards

Christian

Peter

I'm not sure I agree with that, that would mean that any time a flywheel crankshaft or HB was replaced this engine dissassembly and balance job would have to be performed. I not aware that this is the proceedure.

I am aware that usually engines equipt with AT have a different harmonic balancer than engines equpt with MT.

John Roncallo

The mercedes manuals have a procedure for matching flywheels to prevent the unblance problem. Seems that static balance is almost always adequate, and the procedure is simple if you have an adaquate tool.

The flywheels are bolted together 180 degrees apart on the index marks (there is a hash mark on the flange of the crank and on the flywheel -- hard to see, it's just a line stamped in the inside edges). They ar then mounted together on a ball bearing shaft so they can spin freely, and the new one is drilled so that the pair will not return to the same point of rotation when gently rotated (that is, they have the same static balance).

Any good machine shop can do this, I'm sure, also any engine machine shop, but you MUST have the old flywheel! Doesn't matter if they are the same (manual vs auto tranny) so long as the replacement can be drilled to match the old one.

I don't konw what you do if the old one is busted, but I'm pretty certain this won't happen with a Benz flywheel!

Sometimes it doesn't matter and you can just slap any flywhel on at any position and the engine runs fine, sometimes the car will bounce three or four inches on the springs at idle!

One that that can be checked fairly easily is that the index marks are matched. I assume this was done, but R&R of the flywheel is easire than tearing down the engine!

Peter