can't find this info in my 2nd. edition shop manual (1999).

what is the normal temperature range for the transmission

what is the transmission temp. that will set off the "High Transmission Temp" yellow warning light ?

thanks,

Z.

warning light only came on twice, and I can't get it to fault again. No error codes showing. Transmission temp is up to 185 F ( 85 C ) and cools down a bit at rest (idle)

 

How are you measuring the temp??
If you are using a diagnostic device through the CAN bus be aware that the temp will ONLY be available on the network with the selector in DRIVE or REVERSE.

PARK or NEUTRAL will read the ENGINE coolant temp by default. Please refer to TSB 307-06.

bob

 

 

Can't tell for sure, but for the TCM to do a shift adaptation, the oil temp needs to be between 60 and max 105 C.

It can be a couple of things, it actually is overheated, cabling, or temp sensor bad.

attached more info

 

thanks for the attached manual data.

I just changed the transmission fluid , filter, plate, and electrical connector. Subsequently, about 20 miles later, I got one or two yellow warning lights of too high transmission temp. I didn't have my reader with me, so I don't know what the temp was. After hooking it up, I am getting transmission temperatures of 75 - 86 C under normal cruising at a steady speed of 75 mph (120 k/ph). If I floor it and engage the transmission kick-down, and temperature will go up to 92 C and stay there for a while, and slowly come down to the high 80's C. The engine temperature is steady at 90 - 95 C

If I knew at what temperature the warning light comes on, then I would have a better idea how close to danger my numbers are. I was hoping it would be easier to find that specification.

Z

 

it appears to be just electrical, and not actual overheating. The warning light came on for a couple of seconds this morning right after I started the car. The engine and transmission were stone cold, so that eliminates overheating, and my mind is eased considerably.

Z

 

Hey Z,

Did you resolve your transmission electrical issue? I'm about to do a full tranny service and just in case I run into this it would be good to know what happened.

Thanks

 

well, if resolved means have I fixed it , then no, its not been resolved.

But the issue has been narrowed down to the needless change out of the old original conductor plate for a new conductor plate that turned out to be a counterfeit of a genuine Mercedes part.

the knockoff part gives out random and false transmission over heating warnings . The fix would be to reinstall the original conductor plate. But like a
fool I threw it away before I realized the new one was junk.

my advice to anyone thinking about replacing their original conductor plate just because it’s old: DON’T DO IT !

unless the part is broken, it’s going to be better quality than the aftermarket parts. If it has to be replaced, then scour the world for a genuine Mercedes conductor plate. Try to find one that has it’s Mercedes box too, as those are rarely counterfeited.

Z