I have searched this forum for advice and need more.


Car: White 2001 XKR convertible built in June 2000
Problem: Occasionally, not always, when driving at a slightly accelerating speed like on an expressway entry ramp and then flooring it to actually enter the expressway the tranny shifts down and the engine speeds up but the car is not accelerating commensurately with the engine speed. The tranny is slipping. If I momentarily lift my foot up on the gas and then floor it again the tranny locks into gear and away I go.


3 Questions:
1. How do I find out which transmission is in the car?
2. Threads suggest the problem might be low tranny fluid level (there don't seem to be any leaks) or used up "burnt" fluid. Any other possible solutions?
3. There are no error codes from the under dash connector. Is there another code reader socket somewhere else in the car or do ALL error codes come through the one under dash socket?


Don't know what I'd do without this forum. Have learned about changing plugs, O2 sensors, brake light switch, etc from ya'll. Thank you.

 

Update: With more research - apparently the car has a MB tranny and the torque convertor has a drain plug which allows draining it to totally replace all the fluid which is not possible with a ZF tranny.

 

These are pictures of the transmission to help identify it.



Is this the Mercedes transmission? There is no filler plug on the side.


Is there a separate code reader socket for transmissions or are transmission codes read through the same socket as engine codes? I know it's a dumb question but I don't know the answer.

 

Yes it is the Mercedes transmission, yes that is the filler tube photo. The red tab must be broken off to remove the cap. It can optionally be replaced for a dollar part. All codes are read through the same OBDII socket.

Checking the level should definitely be a first step. You will need to purchase a dipstick for the Merecedes 722.6 transmission, widely available over the internet if you do a seach.

 

Thank you WhiteXKR. Maybe someday we can have our cars side by side for a picture. I hate asking dumb questions but how else do I learn? Thanks again.

 

I would check the level as stated above but I'd certainly change the fluid/filter. It's much easier than the ZF transmission, MB used clamps to hold the pan and there isn't a issue with getting them off. You refill thru the tube in the eng bay (that u found). Measure how much you drain, then refill and measure.

There are 3 basic problems that occur with this transmission, you might have a faulty speed sensor which you can replace the electrical plate when changing. They are avail on ebay. This is all fairly easy to do.

Read this and there is a good youtube video on maint.

Mercedes-Benz 722.6 Transmission FAQ - Mercedes-Benz Forum

 

Thank you jamdmyers. Will do.