So in other words, the speedo drive in the manual tranny is different from the on in the auto (Different rotations per mile.)

I've been wanting to swap in a 3.07 or 2.88 but sacrificing speedo and odo accuracy isn't an option.

Apparently so.

r leo
 

did you change anything else like tire size?

tom w

Nope. AFIK, the tires are stock sized, P205R14 Michelins.

i am not sure which car you have, but i dont think a 205 is standard on even the 126 you list in your signature.

and you dont mention the aspect ratio of your tires. there is a big difference in the height of a 70 series vs a 55 series. a 55 would be about right for correct speedo reading i think (without calculating). a 70 series would prob be about 10% off and reading slower than you are going. is your speedo reading too slow? if so it is surely at least partly the tire size.

tom w

IIRC, we're talking about the manual conversion in my wagon. I was wrong about the tires, they're the OEM size, P195-70R14 (FWIW, the OEM size for the SDL is 205-65R15...which is what is on there now). These are the same tires that were on the car when I completed the conversion and that's when it picked up the error. Speedo reads about 10% too high...ie: indicated 75mph is an actual 68mph (per GPS).

that
 

would be indicative of running undersized tires.

and if the speed is supposed to correct for the slip inherent in the automatic it should read slow not fast with the stick.

so i am at a loss for an explanation unless the speedo and rear end dont match. if you know the ratio of the rear end if you post that and the speeds indicated on the speedo we can figure out if it is a matched pair.

tom w

See posts #86, #90 & #96....in synopsis, basically stock except the manual tranny. Speedo indicated correctly before the conversion.

I'm confident that VDO mkes all the adjustments for the various final drive ratios by tweaking the speedo/odo drive gear in the actual speedo head. For example, my I swapped the 3.07 diffy in my 300D for a 2.88. The speedo in the 300D indicated about 4 - 5 mph slow after the swap. I scarfed a speedo out of an '85 that had a 2.88 and installed it in the 300D. Bingo! Speedo is right back on target.

My wagon will never be perfect with the speedos available in the US because there never was a manual/3.07 offered here.

You fellows did read the recent thread posted about changing to the automatic transmission crossmember stopping about 90% of the vibration? It is recently posted. Just thought I would insert this it in case one of you missed it.

This seems to be the exact same problem I am having, so if you don't mind my jumping into this discussion, I will solicit any information available out there. I had my conversion done at a repair shop that has been working on these cars for 35 years at least. At first he thought it might have been the diff. We changed it and the problem is still there. My vehicle is a 1984 300D converted from auto to a 4sp manual.

Carlos,
The car in this thread has recently been upgraded to have a 5-speed Getrag manual transmission from a 240 Euro. You probably know the 5-speed is longer than the 4-speed but still shorter than an automatic. In the conversion, I used the auto's crossmember and rear mount but fabricated a steel tab to extend the tranny's rear mount to the auto crossmember.

http://berryhillfarm.us/benz_stuff/Trannydrawing.jpg

The new box has a similar vibration but not quite as bad as it was with the old gearbox but, one thing that's different is that I now have the vibration when decelerating. Henry Schumann and I put the car on the lift last Saturday and poked and prodded everything, looking for the obvious. Two major things we discovered were: 1) the car needs rear subframe bushings and 2) it needs motor mounts. Additionally, I've installed one of the flex disks facing the wrong direction.

I plan to correct these issues sometime in the next month and will report the results then.

While she was on the lift, Henry loosened all the crossmember and rear mount bolts and the spud nut on the driveshaft. We then shook the engine on it's mounts to 'neutralize' any misalignments and retightened the fastners. I do believe that there was some reduction in the vibration transmitted to the cabin by doing this.

I am pleased to have been able to join the club of "row your own," transmission specialist.. with a vibration issue as well.. In reading this post, and thinking about how my car went together, I am gonna play with the hight of the transmission.. as I am now under the impression that it is too high... If I get anywhere I will surely pass it along..

A real learning thread if I ever saw one. I wonder if a german speaking or writing member posted on the equivelent european site if some relevant information or existing knowledge might come back.

Recycled
 

for new members

Im going through this now.
 

I have the exact symptoms I believe. Gwagon flywheel. Im wondering if going through the flywheel centering process described in the OM617 FSM would help. It looked somewhat tricky. Has anyone done that here before.
I still need to install engine dampeners. Maybe that will help. Plus another Valve adjust/check would be worth it. Those items are on the list of possibilities. At least I have not torn apart the gearbox already. I was considering it. Not before a lot of investigation. Now I think that is less of a possibility.