C36 Transmission Problems - PeachParts Mercedes-Benz Forum

RobertFini · #1 07-05-2006, 11:09 AM

I drove my 1997 C36 (115k miles) out to Indianapolis last week to catch the US Grand Prix; what a letdown that race was, but we still had a great time. We made the 650 mile trip in great time, at an average 65 mph that included a half-hour stop for lunch and gas. The car ran great the whole way, and I can't tell you how much fun it was to be like a shark tearing through schools of guppies for hours on end.

Anyway, the transmission began to act up soon after we arrived. The problem began as a lack of shifting - the transmission would work fine for a while, then give a lurch and stay in whatever gear it was at the time. At first, rebooting (turning the car off and then back on again) restored normal operation but the car eventually went into limp mode, locking in second gear.

It was a real pain in the ass, but we did manage to make it through all the local driving over the weekend. I knew there was no way I'd be able to drive the 650 miles home like that, so I took it to the local dealer (World Wide Motors) in Indianapolis for repair. I was very impressed with their customer service, but the diagnosis of a bad conductor plate ($720 total) seems to have missed the mark because it only lasted for about 300 miles into my journey home. Fortunately for me, I was running in fourth gear when it locked up and I did manage to nurse it home, carrying a 70 mph average and making the trip in 9:20 elapsed.

Can anyone offer any advice on what might be causing everyone to think that I got another bad conductor plate? What might be causing these indications? Is it possible that I did get another bad conductor plate? If it's not the conductor plate, what else could it be?

Best Regards,
Rob

Melcher · #2 07-05-2006, 01:08 PM

If they're saying it is a bad condcutor plate again, then it should be replaced under warranty at no cost to you, seeing as how you bought it from a dealership. It's a "parts warranty" issue.
After that you may be looking at a control unit or valve body issue. I am assuming there was no visual evidence of wear/internal failure because they would have seen that and advised you when they (Indianapolis) pulled the valve body out the first time.
Also conductor plates are often replaced due to speed sensor faults. The speed sensors are integrated into the plate. I've often found codes for speed sensor faults when there is fluid in the control unit. Ask them to check for fluid contamination in the ETC unit, they shouldn't charge you to just check. Good luck.

RobertFini · #3 07-14-2006, 03:22 AM

So, my local dealer diagnosed the problem as another bad conductor plate after reading another #109 code for a faulty speed sensor. They replaced the plate that the Indianapolis dealer installed, under warranty at no cost to me (yah freaking hoo). My dealer tells me that it's as good as new and off I drive. I scoot the 40 or so miles home and it runs great - kicked ass like at always has.

Later THAT SAME DAMN NIGHT, the car once again locks in gear and eventually goes into Limp mode. It is now back at the dealer, and they're saying that it's looking like the entire transmission needs replacing. This is based on some test that they're performing that is supposed to return a value of something like 620 and my car is reading 8000. They'll do some more tests to confirm that it needs replacing, and my Assistant Service Manager has promised me that he'll go to bat for me with MBUSA to try to get some "goodwill" that his dealership can use to offset the estimated $4500 cost for a new transmission, if that is in fact the remedy for my troubles.

Can anybody tell me why a Mercedes-Benz that's nine years old with about 115k miles on it should be needing its third transmission?

Best Regards,
Rob

AMG CE 36 · #4 07-14-2006, 04:33 AM

I am waiting for the day they want you to replace the whole car when a light bulb is out...

But seriously, it seems that the 5-speed transmissions isn´t that bullet proof as the 4-speed. I have 4-speed in my CE 36 with no problems (yet) ...

benzfan · #5 07-14-2006, 10:00 AM

Those transmissions are well known for an O-ring leakage at the connector, soaking the connector plug in fluid. This will cause the faulty conductor plate code. I would pull the plug to see if it is wet with fluid before doing any more shot-in-the-dark repairs. During routine fluid replacement, this O-ring should be replaced.

MBtech21 · #6 07-16-2006, 01:18 PM

I'm willing to bet the trans module is full of fluid- that will cause exactly what you are talking about- the conductor plate leaks past the pins , up the harness and into the module. Very rare that the trans would fail- especially intermitantly, if a clutch pack is burned up, or a seal blown out, they don't work ok sometimes...