420SEL auto tranny question - PeachParts Mercedes-Benz Forum

BENZ-LGB · #1 08-22-2003, 12:31 AM

I have a 1991 420SEL with 238K miles on the ticker. The car runs fine. The engine is smooth. The tranny shifts well, on time and powerfully.

The other day, however, the tranny did something weird. After driving for about 3 miles, the tranny wouldn't shift out of first. The engine would rev up, but no shift. When the engine revved, the economy (vacuum) gauge wouldn't move past the economy (left) side. In other words, it would just stay put.

I pulled over the side of the road and the engine was idling smoothly, ruling out some sort of vacuum failure.

I put the car in PARK, turned the engine off, and then re-started it.

the car then ran fine and shifted as always--right on point.

The car, engine, and tranny have been running A-OK since then, but now I am somewhat worried about a major trans job.

I am taking my car for a regularly scheduled service on August 26. My echanic will then take a gander at the tranny.

Before I take the car to him, I'd like to hear from ayone here if they have had the same problem with the tranny. And if so, what was the solution?

Any ideas, suggestions, etc., will be greatly appreciated.

sixto · #2 08-22-2003, 02:22 AM

Is the carpet or floor mat tangled in the kick down switch under the gas pedal?

Sixto
95 S420
91 300SE
87 300SDL
83 300SD

#3 08-22-2003, 02:38 AM

I recently had the same issue with my tranny - would not shift out of first, despite re-starting and all.

Had the car towed back to my house.Re-started next day and still not shifting out of first.

The tranny had to be rebuilt!

Diagnosis : Clutch material within the tranny disintegrated and plugged up fluid channels.

Cost of rebuild : $1500

I did disconnect the kickdown switch (in case it was sticking) but still the same problem.You may want to do this check first before going any further.

Good luck.