my transmision in my SL goes from 3rd to 5th(overdrive) without shifting through 4th. it started this with no warning,ie noises,slipping or other problems associated with trannys going bad. i think its electrical and i took it to my dealer to check. they checked the overdrive switch on the shift lever, changed a selinoid valve assbly , and 1 month later admitted they were stumped. i told them to take the new parts off which the did and i picked my car up (after paying$ 500.00 for them to practice) and drove it home with the same problem. oh i forgot, they also said the only way to fix the car was to put in a new tanny. i heard of a shop in sfo area that specializes in mb trannys, so i called them and explained my problem. very helpful and i got the feeling they new what they were talking about. they said the problem was electrical and putting a new tranny would not fix the car. possible problems, wireing harness shorting out, the computer control box on the firewall(egs box).i called the dealer to have them talk to this shop and by the time they got around to it the mechanic had left for England for a month. H E L P i'm fairly mechanical having overhauled 2 previous mb diesels,but i need some place to start. thanks for any help 92 300 sL 68000mi.

The early overdrive solenoids cause this problem. Have them look in their RED Fische under topic 27A93062. The replacement solenoid is part # 124-304-04-90. Did they charge you for this part number?? Also did they read codes from the trans ECU & erase them. IF the electrical connector is the problem then the computer will have many codes.

300 sL TRANNY NOT FIXED YET
 

AFTER CHECKING WITH THE DEALER THEY SAID THEY REFERED TO SERVICE BULLETIN THAT YOU MENTIONED, AND THAT WAS THE SERVICE THEY PERFORMED. THEY ALSO SAID THAT MY 300 HAD BEEN UPDATED TO THE NEW COMPUTER CONTROL BOX I.E. THE ONE THAT IS LOCATED ON THE RIGHT HAND FIREWALL.COULD THIS HAVE GONE BAD I UNDERSTAND THEY COST ABOUT $800. IDONT MIND PAYING THIS IF IT WILL FIX THE PROBLEM. WHAT IS YOUR BEST GUESS.THAKS FOR YOUR H E L P .GREGHSKJ 300 SL

I STILL NEED HELP
 

DID YOU FORGET ABOUT ME WITH THE NEW YEAR HOLIDAY AND ALL. I STILL NEED HELP WITH MY TANNY PROBLEM. GREGHSKJ 300 SL

OLD Post
 

Just didn't read latest post, SORRY. Have you had the Trans codes read by dealer or repair shop?? Did they use the suggested part number, on your receipt? If they used the old number the problem would be the same. The only other problem I've seen is the switch/detent on the shifter itself! Re-reading computer codes should point a finger at the problem!