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LMM transmission freezing problem

6K views 6 replies 5 participants last post by  mohok 
#1 ·
I have a 2007.5 LMM. It has 110k miles. It's pushing 40's.

In the winter when it gets bellow about 29 degrees, On cold starts the transmission is always stuck in 3rd gear. It won't go into reverse or anything. I have to let the truck warm up then turn the truck off for about 5 minutes and then the transmission runs fantastic. It gives me anywhere from 5-12 engine codes every time it does it.

I have always been able to clear the codes after the issue.

A few days ago it got into the lower 20's and the trans spilled out about a half quart of fluid onto my driveway overnight (Never leaked before). I started it up and let it warm up, Turned it off for 5 minutes and it drove fine however I wasn't able to delete all the CEL lights. I can clear the codes and not even start the truck and the codes are there again.

truck didn't leak at all after that night until last night when it dropped into the 20's again and it did the same thing. Leaked a good amount onto the driveway, started and ran great after warm up but I still can't get the codes to clear.

Here are the codes that I can't seem to clear-
P0700
p0877
p0694
p0761
p0756
p0751

I drive like an old man, The trans doesn't slip, Doesn't and has not gone into limp mode.
I feel like the fluid has to be freezing?? Any suggestions?

Thanks in Advance.

Jason
 
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#2 ·
Where is it leaking from? Dex VI (factory fluid) has a pour point of -54F, your not even close to having it freeze or even thicken up considering it's a lower viscosity fluid than the Dex III the transmission was designed to use.

Mine has done some strange things when it's extremely cold (-20F or colder) and I finally found that I had a weak battery that was dropping voltage, new batteries and I haven't had an issue since. Low voltage will cause the trans to do all sorts of things.
 
#3 ·
Low voltage issues will push out trans fluid?

What's the service/maintenance history on the trans?
 
#7 ·
LMM Cold Weather Tranny Problem

Make sure your tranny fluid lines are not leaking. Factory lines have a defect in cold weather. The crimps from rubber to metal will leak. GM finally recognized the problem and a few years back would reimburse for dealer replacement. I ordered an Alligator Replacement Kit and had my Dealer (friend of mine) install
them for me. GM actually gave me a refund for either dealer cost of the 3 lines or labor, I'm not sure which at this time. I was flabbergasted to say the least. GM didn't put out a recall because not all lines failed. I think they have since corrected the problem.:drink
 
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