C32 Transmission Maintenance and Repair
07-16-2011, 11:40 PM
#1
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Black on Black stock ' 03 C32
C32 Transmission Maintenance and Repair
I've searched, but didn't find this particular experience, so here goes.
I bought my C32 with 60k miles, CPO, 3 years ago. No problems. I asked on the forum about tranny service, and it was the consensus that fluid should be changed at 90k. (Supposedly, MB trannies are 'sealed for life' but I don't think so...) My mechanic also concurred that it was originally 'sealed for life' but I should change the fluid and filter before 100k. I did that about 9 months ago at about 105k. The tranny was working fine, mind you, but I want to keep the car for as long as possible, so I thought I should change it. Tranny had no issues, ever, before fluid flush. After the fluid and filter change, worked the same, but 3 months later, the problems start.
-->> After the fluid change, it started have these symptoms: Engages and starts good. the shift from 2nd to 3rd is a little soft, but when it does grab, it's kinda jerky; reminds me of someone who doesn't know how to use a clutch. Higher gears are all fine, incl reverse.
Then, one day, about 6 months ago (3 mos after fluid change) the tranny fails. The following symptoms are the same for all three failures: The car will drive a little in first, up to about 2000 RPM, and then it just slips out and revs like neutral. If you stop car, and try to drive again, no drive or reverse. If you put in park, turn off and wait a few minutes, when you put in drive it will engage again for first gear, but slips out over 2000 or so. Once it slips out, will only engage if it's put in park with engine off for a few minutes, but only first gear, and then slips out again.
I took to mechanic, he says it was most likely the solenoid assembly. About $450 P/L. He showed me others in shop as example of what happens. Drop the pan, shows me the part. It's worn, but not worn out, but job is done, and he says it would gone soon enough, and he'll give me credit for the part if I do end up rebuilding, that he estimates will be in the next 30k miles anyway. Ok, drive off, everything good. Lasts about 5 months.
A month ago, Symptoms return: Slips out after 1st, won't drive after the slipout, only engages if it sits for a few minutes with engine off in park. Tow to Mech, He says it's rebuild time. Normally about $1,600, he's gonna credit $400 of recent parts and work as he said he would, so he rebuilds tranny for $1200. Get the car, drives good, all is well. Been driving it for 4 weeks, and I was 'breaking it in gently' bc I want to keep car for a long time.
Yesterday, without warning, Failure symptoms return. It's 5:45 PM, and mech has closed at 5:00 pm until Monday. I happen to coast to a stop at a tranny shop (imagine that) and I tell the guy what's going on. He says that if the rebuild was done and the lines going to the cooler were not thoroughly flushed out, the remains of the previous tranny failure could get back into circulation and eventually cause the filter to clog, in which case it would exhibit the exact symptoms I related to him. He says the filter clogs, pump loses suction, tranny loses hydraulic pressure, and slips out of gear. When it sits in park for a few minutes, the pump can have some fluid return to it, which is just enough for it to engage 1st, but soon again loses suction and slips out.
I bought the filter from him and was considering changing out filter, as mech doesn't open till Monday and I don't want to get a rental, but reconsidered against doing any work on it this weekend bc I don't want mech to say that I tampered with the tranny and void out my 12k/12m warranty. Had it towed home.
1) has anybody had the symptoms I described?
2) Do the prices sound reasonable, bc the dealer wanted 3k for rebuild.
3) Why does it have the same exact symptoms for the 3 failures?
4) Is the second mech at tranny shop correct in saying the cooling lines were not flushed and if so, would driving it a little ways with low pressure/slipping out put excessive wear on what is supposedly a completely rebuilt tranny? In other words, does slipping out bc of low pressure burn up fluid/bands/clutches etc, and this freshly rebuilt tranny now has the equivalent of a year's worth of use on it?
5) This has been my mechanic for this car since I bought it, everything else has been reasonable and very well done, he's always got a full shop of work, and 'been good to me' so to speak, so I don't want to suspect that the tranny wasn't in fact rebuilt, but how in the world does a rebuilt tranny fail after 4 weeks of light use?
BTW, these symptoms have NOT been accompanied by any banging, clunking, grinding, leaking or anything else besides simply slipping out after first, and after ebuild, the mech said that the rest of the tranny was mechanically sound and the pump was good.
Any comments about rebuild experience, fluid changing experience, and the solenoid plate are welcome, and I thank you in advance for taking time to respond,
Tino
I bought my C32 with 60k miles, CPO, 3 years ago. No problems. I asked on the forum about tranny service, and it was the consensus that fluid should be changed at 90k. (Supposedly, MB trannies are 'sealed for life' but I don't think so...) My mechanic also concurred that it was originally 'sealed for life' but I should change the fluid and filter before 100k. I did that about 9 months ago at about 105k. The tranny was working fine, mind you, but I want to keep the car for as long as possible, so I thought I should change it. Tranny had no issues, ever, before fluid flush. After the fluid and filter change, worked the same, but 3 months later, the problems start.
-->> After the fluid change, it started have these symptoms: Engages and starts good. the shift from 2nd to 3rd is a little soft, but when it does grab, it's kinda jerky; reminds me of someone who doesn't know how to use a clutch. Higher gears are all fine, incl reverse.
Then, one day, about 6 months ago (3 mos after fluid change) the tranny fails. The following symptoms are the same for all three failures: The car will drive a little in first, up to about 2000 RPM, and then it just slips out and revs like neutral. If you stop car, and try to drive again, no drive or reverse. If you put in park, turn off and wait a few minutes, when you put in drive it will engage again for first gear, but slips out over 2000 or so. Once it slips out, will only engage if it's put in park with engine off for a few minutes, but only first gear, and then slips out again.
I took to mechanic, he says it was most likely the solenoid assembly. About $450 P/L. He showed me others in shop as example of what happens. Drop the pan, shows me the part. It's worn, but not worn out, but job is done, and he says it would gone soon enough, and he'll give me credit for the part if I do end up rebuilding, that he estimates will be in the next 30k miles anyway. Ok, drive off, everything good. Lasts about 5 months.
A month ago, Symptoms return: Slips out after 1st, won't drive after the slipout, only engages if it sits for a few minutes with engine off in park. Tow to Mech, He says it's rebuild time. Normally about $1,600, he's gonna credit $400 of recent parts and work as he said he would, so he rebuilds tranny for $1200. Get the car, drives good, all is well. Been driving it for 4 weeks, and I was 'breaking it in gently' bc I want to keep car for a long time.
Yesterday, without warning, Failure symptoms return. It's 5:45 PM, and mech has closed at 5:00 pm until Monday. I happen to coast to a stop at a tranny shop (imagine that) and I tell the guy what's going on. He says that if the rebuild was done and the lines going to the cooler were not thoroughly flushed out, the remains of the previous tranny failure could get back into circulation and eventually cause the filter to clog, in which case it would exhibit the exact symptoms I related to him. He says the filter clogs, pump loses suction, tranny loses hydraulic pressure, and slips out of gear. When it sits in park for a few minutes, the pump can have some fluid return to it, which is just enough for it to engage 1st, but soon again loses suction and slips out.
I bought the filter from him and was considering changing out filter, as mech doesn't open till Monday and I don't want to get a rental, but reconsidered against doing any work on it this weekend bc I don't want mech to say that I tampered with the tranny and void out my 12k/12m warranty. Had it towed home.
1) has anybody had the symptoms I described?
2) Do the prices sound reasonable, bc the dealer wanted 3k for rebuild.
3) Why does it have the same exact symptoms for the 3 failures?
4) Is the second mech at tranny shop correct in saying the cooling lines were not flushed and if so, would driving it a little ways with low pressure/slipping out put excessive wear on what is supposedly a completely rebuilt tranny? In other words, does slipping out bc of low pressure burn up fluid/bands/clutches etc, and this freshly rebuilt tranny now has the equivalent of a year's worth of use on it?
5) This has been my mechanic for this car since I bought it, everything else has been reasonable and very well done, he's always got a full shop of work, and 'been good to me' so to speak, so I don't want to suspect that the tranny wasn't in fact rebuilt, but how in the world does a rebuilt tranny fail after 4 weeks of light use?
BTW, these symptoms have NOT been accompanied by any banging, clunking, grinding, leaking or anything else besides simply slipping out after first, and after ebuild, the mech said that the rest of the tranny was mechanically sound and the pump was good.
Any comments about rebuild experience, fluid changing experience, and the solenoid plate are welcome, and I thank you in advance for taking time to respond,
Tino
07-18-2011, 12:04 AM
#3
Super Moderator
wow sorry about the bad luck I don't really have anything that can help you but let us know how it goes tomorrow. It might be as simple as not enough fluid or as bad as the rebuild did not go well.
07-18-2011, 02:24 AM
#5
Super Moderator
Very good questions I was scared to ask it 
Because obviously if it was not used it could really F up some things as well as make the Indy a complete idiot which would also scare me if he says he rebuilt the transmission. Lets hope he used the proper oil since it can be found so cheaply
Because obviously if it was not used it could really F up some things as well as make the Indy a complete idiot which would also scare me if he says he rebuilt the transmission. Lets hope he used the proper oil since it can be found so cheaply
07-18-2011, 07:26 AM
#6
Super Moderator
Please get this car onto a Star & post the transmission codes that are being stored. Stops guessing. The 722.6 transmission is tough but should be serviced every 39K miles with 236.14 fluid & a new filter. You could well have a clogged fluid line or valve body orifice or filter. Could be the conductor plate again but why? Have you checked the fluid level? It could be low. These transmissions are not filled for life - especially on an AMG where they have to tolerate high torque changes.
The fact that it is not going into limp is a good sign. The usual failure on the 722.6 at very high miles in taxi service is the 1st to second one way clutch assembly. If this were the case it would have a very harsh change.
Does your car have a Valeo radiator & has the fluid been checked for glycol contamination? Valeo radiators of your generation were known for leaking coolant into the transmission cooler. Replace with a Behr.
The fact that it is not going into limp is a good sign. The usual failure on the 722.6 at very high miles in taxi service is the 1st to second one way clutch assembly. If this were the case it would have a very harsh change.
Does your car have a Valeo radiator & has the fluid been checked for glycol contamination? Valeo radiators of your generation were known for leaking coolant into the transmission cooler. Replace with a Behr.
