'89 420SEL Transmission: Replace or Rebuild? - PeachParts Mercedes-Benz Forum

goldstone · #1 12-07-2004, 12:12 PM

As soon as I thought the new modulator and Bowden Cable adjustments had given my tranny a new lease on life, I'm back to square one

THE FACTS:
Over Thanksgiving weekend I put about 150 miles on my 420 getting to our destination. Shifted into reverse and backed down a long driveway. Upon returning to Forward, the whine characteristic of reverse continued (only not so pronounced.) Whine is persistent, speed sensitive, and present in all gears and in neutral. No problem with shifting though... Transmission works fine except for the annoying whine.

When I returned home, I listened carefully, and the whining is definitely coming from inside the bell housing. I R&R'ed the fluid, filter, and gasket. I do this regularly (every 25 thousand miles or so) Absolutely no sign of metal shavings or other impurities in either the pan or filter.

QUESTION:
I don't feel competant to rebuild a transmission on my own, and given the different possible diagnoses: tranny pump, planetary gear, bearings, seals, pistons, et al. the bottom line question for me is this: With 245,000 miles on the original tranny, am I better off having a qualified tech rebuild her or should I simply have the tech swap in a replacement? (Seems to me the net cost is not all that different...)

Also, if replacing the entire tranny (and torque converter?) is the concensus here, can I rely on German Star rebuilts? Other suggestions for quality rebuilts at a fair price?

THANKS!!!

goldstone · #2 12-10-2004, 01:43 AM

Bump...

lino · #3 05-10-2005, 08:28 AM

Do you have an update for us? How did you make out?

goldstone · #4 05-10-2005, 11:54 AM

Had no better economical choice than to replace the tranny and torque converter. (Repair would have cost more.)

The original torque converter was fused so tightly to the original tranny that my mechanic couldn't readily separate them. (He didn't want to get too rough since he knew I needed to return the old one to get my core charge back from German Star.)

Ron at German Star was GREAT: very knowledgable and honest to deal with. My tech was very impressed with the quality of the rebuilt tranny, and the net price of the tranny and torque converter I purchased was very fair. On the basis of my experience, I can recommend Ron and German Star to you without reservation.

I did have an oddball problem when installing the new parts which I detailed here:
Does this sound like a flex disk problem on my 126?
After dealing with this situation, everything is cool. The car drives like new once more, and I'm good to go for the next 250,000 miles

lino · #5 05-10-2005, 12:30 PM

Congratulations and good luck!
Btw, what ATF are you using and how much did the tranny and torque converter cost you? (if you don't mind)

goldstone · #6 05-10-2005, 12:52 PM

Thanks, "Lino"!

Here's the link to German Star's price list:
http://www.germanstar.net/tranmb.htm

It cost me an additional $180 for round trip shipping ($90 to get the new unit and $90 to return the core.)

I used owners manual approved Quaker State ATF for the initial fill, which I bought at WalMart literally on my way to the mechanic for the transplant. I service the tranny myself every 20,000 miles, and have decided to switch over to Mobil1 next time and to continue using sythetic thereafter. (I'm dubious as to whether it really makes a difference, especially given regular changes and maintenance, but I figure it can't hurt, and the cost of the synthetic fluid is marginal in comparison to the value I place on this new tranny...)

Cheers!

lino · #7 05-10-2005, 01:43 PM

Thanks for the info. I already started my new tranny with Amsoil synthetic ATF right from the start. So far so good since I only have 5 miles on the new rebuild

. I got my car back last Friday.