722.6 Transmission with common problem but accompanied by a strange noise
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Joined: Aug 2014
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2004 C320 4Matic
722.6 Transmission with common problem but accompanied by a strange noise
I have a 2004 C320 4Matic wagon. Yesterday morning, all was great, shifted fine, no noises. Last night, suddenly the trans went into Electric Limp home mode, and I slowly/carefully drove it about one mile to a safe location. The car would pull for a few hundred yards, then slip out of gear. After 10 seconds or so, I could restart, engage gear, and move again. Car was flatbedded home, and I began to disgnose. My generic OBD II says P0715 and P0730. It slams into reverse and drive pretty hard, and I interpret all of this as a classic/textbook case of a failed speed sensor. I was planning to replace the conductor plate- EXCEPT, there is this high-pitched, sort of clicking/whirring that I hear in park, and in reverse, neutral and drive. Frequency increases with RPM, and it sounds like someone flicking the teeth on an old hair comb (if you are old enough to remember what those are!).
A bit of history on the car- 104K, fluid was changed (not flushed) with a filter about 20K ago, and pilot bushing was changed as a precaution. No current leaks, and only one minor issue before last night- a hard 1-2 shift only when cold, maybe the first minute or so. Fluid looks and smells OK today, and fluid level is good, per my official Mercedes trans stick that I had to buy after the fact! Otherwise, the car has performed well, until last night.
I hope to have access to a Carsoft unit later this week, and I will verify the P0715 and P0730. I plan to go ahead and order the conductor plate and filter set- am I on the right track? Is the noise indicative of a different issue?
Thanks!
A bit of history on the car- 104K, fluid was changed (not flushed) with a filter about 20K ago, and pilot bushing was changed as a precaution. No current leaks, and only one minor issue before last night- a hard 1-2 shift only when cold, maybe the first minute or so. Fluid looks and smells OK today, and fluid level is good, per my official Mercedes trans stick that I had to buy after the fact! Otherwise, the car has performed well, until last night.
I hope to have access to a Carsoft unit later this week, and I will verify the P0715 and P0730. I plan to go ahead and order the conductor plate and filter set- am I on the right track? Is the noise indicative of a different issue?
Thanks!
Thread Starter
Newbie
Joined: Aug 2014
Posts: 3
Likes: 0
2004 C320 4Matic
Update to Issues
Thanks for all the help
The W203 Wagon with transmission issues is back on the road. Changing the conductor plate solved the shifting problems, as well as the whirring noise that increased with engine RPM in all gears including neutral and park. This caused me to invest in Carsoft 7.4, and I am very pleased with that system, too.
There were other stray codes, but the P0715 led to a speed sensor code, and the conductor plate seems to have solved that.
Mybroken C230 Coupe is also repaired. Timing chain and tensioner job is not difficult, but it should not be required on a two owner, 74K mile car that has been maintained much better than recommended. Shame on Mercedes Benz- Das Beste oder nichts (The best or nothing at all) is merely an advertising slogan!
The W203 Wagon with transmission issues is back on the road. Changing the conductor plate solved the shifting problems, as well as the whirring noise that increased with engine RPM in all gears including neutral and park. This caused me to invest in Carsoft 7.4, and I am very pleased with that system, too.
There were other stray codes, but the P0715 led to a speed sensor code, and the conductor plate seems to have solved that.
Mybroken C230 Coupe is also repaired. Timing chain and tensioner job is not difficult, but it should not be required on a two owner, 74K mile car that has been maintained much better than recommended. Shame on Mercedes Benz- Das Beste oder nichts (The best or nothing at all) is merely an advertising slogan!
