Flex Plate Question

[Duke1]

Hello,

Wanted to see what you all thought about the following. I have a 78 W116 with 617.950 engine. I recently had a loud rattling noise appear from the bottom end of the engine. I was thinking that it was exhaust...but I put it up on the jacks today.

Based on what I've read on the site about flex plates and the associated noise that goes with them as they deteriorate, I inspected and found a crack in the flex plate.

My question is as follows. Can a motivated but shade tree mechanic do this repair? It looks to be a pretty big deal..or am I just intimidated by what I've never tried before? If I did try to take this on, are there good reference materials I can lay my hands on that deal with dropping the trans...because once it's dropped it looks to be a straight forward repair from there.

The indy quoted me parts ($50ish) and 7 hours of labor at $93 and hour. OUCH.

I'd love to hear your thoughts.

The car runs great and appears to have lots of life left in it.

Thanks,
Duke 1

PS- I checked both my flex discs and they look new, and if I'm not mistaken were replaced by the PO about a year or two before I got the vehicle.

[barry123400]

Well I do not like the concept of doing it on the flat of my back. A pit or hoist is much preffered. In my opinion though the average guy can do it. Tens of thousands have over the years on many cars.

If you opt for having a garage do it check with an auto transmission place. Their time charge should be much less as they are removing and installing them as a constant diet.

[junqueyardjim]

The job is simple and straight forward. But it is heavy duty work, not good for anyone who is physically challenged. The Indy wants $700.00 approximately with parts. If he is a good mechanic I would let him do it. It is a totally nasty, messy, greasy and dirty job!

[Duke1]

Thanks guys for your answers. I'm still torn. I spoke with the tranny shop I go to and he quoted me $450 plus parts...which is much improved.

From a purely educational standpoint...I'd love to try it, but I'm still on the fence. I also haven't found any good reference material on how to drop it, does the HAYNES manual cover this?

Still thinking.

Duke1

[treetrimmer]

Reviving this thread. I agree that this would be a nasty job on the ground but it's a piece of cake in general to R&R the trans on that car. I have the same car w/ the same problem, (w116 300SD w/ broken flex plate). Do I need to use new flywheel bolts or can they be re-used? TIA.

[t walgamuth]

IIRC they could be either reusalbe or not. Some mb bolts for special applications like this are stretch bolts. In general many of the benz stretch bolts can be measured to see if they are reusable.

[treetrimmer]

While I appreciate the response, I need to actually know if these bolts are re-usable. Any MB techs reading this who know if these are stretch bolts, (angle torque), or not? Does anyone have the torque spec for them? That would answer the question. It's a 1980 300SD. TIA.

[1960mog]

First 40nm , then 90° angle.
Mark the flywheel to the crank, before you remove the bolts.
I always reuse the bolts, never had a problem.

[treetrimmer]

Can anyone tell me the flex plate/torque converter tightening torque? Thanks a lot, not near my manuals.