Chevy and GMC Duramax Diesel Forum banner
  • Hey Everyone! Enter your ride HERE to be a part of this months Ride of the Month Challenge!

1 - 20 of 25 Posts

·
Registered
Joined
·
22 Posts
Discussion Starter #1
Hey guys I am having some trouble with my transmission getting too hot. I have a 2006 GMC Sierra 3500 with 140,000 miles on it. 6.6/Allsion. First I was driving home in traffic on a very cold day. I had remote started my truck and it setting idling for a while and I believe at the time I had the elevated idle on. I was in traffic on the interstate for 45 minutes of stop and go. I noticed on my programmer that my TFT had reached 230 degrees and it normally runs right around 100 degrees above ambient temperature. It was in the twenties that day. I finally got going normal interstate speed and it cooled down just a little. I got home and noticed a weird smell. I wrote it off as stuck in set and go traffic. It snowed a day or two later and I seen some tranny fluid on the ground at the front of the truck. It was the normal leaky transmission lines. I purchased three custom hydraulic lines and replaced them. I drained the tansmission fluid out and it was pretty nasty since I had drained it and replaced the spin on 6 months before. So i decided to use the hoot method but I had no idea how low my transmission fluid was prior to starting the process. So i repalced both filters and cleaned the pan really good. I put in 8 quarts of fluid and tried the hoot method and only got a little fluid out of the line and noticed clean fluid coming out of the side of the transmission where i had disconnected the upper line. ??? So I put the line back in and added more fluid and drove the truck down the road to get it up to operating temp. It reached 220 degrees by the time I got back home. I put my hand on the line on the left side of the transmission cooler and it was much hotter than the one on the right and the cooler itself didnt seem very warm. Now i do have a small kink in the rubber hose from the top of the radiator to the left side of the trans cooler but it doesnt seem like much of a kink. i think i do not have my hoses backwards but not 100 percent sure. the way it appears to me right now is the line from the trans to cooler runs to the bottom of the radiator and then the top radiator line runs to the left side of the cooler "if facing the truck". Then the right line on the cooler runs back to the trans "from cooler". so it looks like to me that fluid is pushed up through the radiator and runs down to the cooler and then back to the radiator. I am lost here guys. I will be replacing the slightly kinked line as soon as I can get down to the shop that made it too short. But do I have the lines correct? or any other ideas? Thanks a ton Bobby
 

·
Registered
Joined
·
22 Posts
Discussion Starter #3
Doesn't look dirty to me as far as bebris or bugs.
 

·
Registered
Joined
·
4,016 Posts
I seen some tranny fluid on the ground at the front of the truck. It was the normal leaky transmission lines. I purchased three custom hydraulic lines and replaced them. I drained the tansmission fluid out and it was pretty nasty since I had drained it and replaced the spin on 6 months before. So i decided to use the hoot method but I had no idea how low my transmission fluid was prior to starting the process. So i repalced both filters and cleaned the pan really good. I put in 8 quarts of fluid and tried the hoot method and only got a little fluid out of the line and noticed clean fluid coming out of the side of the transmission where i had disconnected the upper line. ??? So I put the line back in and added more fluid and drove the truck down the road to get it up to operating temp. It reached 220 degrees by the time I got back home. I put my hand on the line on the left side of the transmission cooler and it was much hotter than the one on the right and the cooler itself didnt seem very warm. Now i do have a small kink in the rubber hose from the top of the radiator to the left side of the trans cooler but it doesnt seem like much of a kink. i think i do not have my hoses backwards but not 100 percent sure. the way it appears to me right now is the line from the trans to cooler runs to the bottom of the radiator and then the top radiator line runs to the left side of the cooler "if facing the truck". Then the right line on the cooler runs back to the trans "from cooler". so it looks like to me that fluid is pushed up through the radiator and runs down to the cooler and then back to the radiator. I am lost here guys. I will be replacing the slightly kinked line as soon as I can get down to the shop that made it too short. But do I have the lines correct? or any other ideas? Thanks a ton Bobby
It should run through the radiator one time. Sounds like it may be routed wrong. The radiator functions serves to warm up the tranny fluid on cold days. That is the only purpose of it. Make sure fluid runs through the rad first, THEN the TOC, then to the tranny-in
 

·
Registered
Joined
·
44 Posts
Yea cooler is blocked dude at least on my three trucks I had that was the prob
 

·
Registered
Joined
·
22 Posts
Discussion Starter #7
I am going to check the cooler first since it should be the easiest to test. Thanks guys
 

·
Registered
Joined
·
22 Posts
Discussion Starter #8
Well I removed the Cooler and it is not blocked. I then disconnected the line that runs from the top of the radiator to the passenger side of the cooler and put a hose on it to see if it was maybe the radiator blocked. It flowed fluid out but I also got fluid come back out of my cooler where i disconnected the line. ??? I ran some fluid out as I was overful with fluid. I then hooked that line back up and did the same with the other to see if it was coming through and to drain a little more out. It came out both lines also.??? So i put it back together and checked the cold levels and hot levels and all seems fine. I let it idle for a while and drove it around a while. it seemed fine. Transmission temp got up to 170 ish and stayed there even on the intersate. Then coming back i noticed the temp started climbling again. It got up to 235 ish and my check engine light came on. I now have 4 trouble codes po762 shift solenoid c stuck on, po741 torq converter clutch cic perf/stuck off, u0100 lost commm with ECM/PCM A, and po700 tran ctrl sys error. It seems to be stuck in 4th gear on the way home. I do have a trans go jr in it that has been in there 6 months with no issues. I just replaced some leaking lines with hydraulic lines and changed both filters and fluid.
So after getting home I put my hand on the cooler and it is cold,so i checked the lines on the side of the transmission and the from cooler line is hot as heck and the from cooler line is cold. the transmission pan is hot as heck. The only other thing I done was went to the car wash and sprayed engine degreaser on the transmission and used the car was pressure washer to rinse it off. I am totally lost now?
Any ideas guys? Thanks for any and all help
 

·
Registered
Joined
·
641 Posts
Get in touch with Mike L w/ inglewood Transmission located in So Cal he has a larger cooler for the Allison and more volume flow. Fits in factory location. and good $$$$

Better then Stock

7148707300
 

·
Premium Member
Joined
·
2,267 Posts
Your "Custom Hoses", Print on outside doesn't mean jack, whats the "TRUE" I.D. of the hose?
 

·
Registered
Joined
·
44 Posts
yeah larger hoses larger cooler look i agree with vrabel ya know ive seen where a brand new hose collapses inside like a brake hose or a coolant hosealthought if you look through it and its clear then that anit the case but to me i run just a shade more fulid or less fulid depending on the climate now in my durango now i am running about a half quart lower fulid in it cuz its cold and to mean it seems to do better as far as shifting etc. but warm i always try to put a 1/2 quart or 1 quart over and on the freeway ive noticed a big difference but BUT.... my truck has about 300k on motor and trans so yeah I know its werid but to your prob me sounds like bigger lines and bigger cooler and maybe your factory cooler in the loop too. I ve seen my gpa do that to his conversion van that is gmc of course lol and he has i think 350k on his trans but the motor has been on its last legs but still ticking

sry for rambling on I do that time to time just made me remember some good memorys lol
 

·
Premium Member
Joined
·
2,267 Posts
My point was is that some have hoses made and the I.D. is smaller, thus causing a restriction in flow, causing over heating.
 

·
Registered
Joined
·
44 Posts
also on the I.D. of the hose sry went off track some yeah that will have alot to do with that i.e. smaller hose=less fluid BIGGER HOSE= more fluid lol
 

·
Registered
Joined
·
44 Posts
yea i corrected my self damn this cold
 

·
Registered
Joined
·
611 Posts
Twisted hose.

Friend of mine left his tranny on the side of interstate one day because he had a bad/twisted line from the factory! granted he had like 1000 miles on it. Best part is GM told him has tranny could not possibly overheat, must be a bad gauge. 200 mile later they were towing it and his camper.
 

·
Registered
Joined
·
22 Posts
Discussion Starter #16
Does anyone know if the sticking valves or solenoids would cause the trnamission fluid not to circulate through the cooler/radiator?
 

·
Premium Member
Joined
·
264 Posts
you might want to consider a good transmission repair shop...maybe a lot cheaper than having to pay to rebuild a burn't out allison IMO
 

·
Registered
Joined
·
44 Posts
ok now go to the parts store buy you some seafoam for your transmission its a white can red stripes now pour the whole thing in it and do it after the tranny has been running for 20 minutes then pour it in if that dont work you need to go to a trans shop but like u asked if the valves were sticky well.. follow this one and a question for everyone here

If you going up and down hills now you go up a hill ur going good and right at the top you have no brakes nothing but your going down that hill and at the bottom you have brakes? now can you tell me how this would happen and fyi ive had this happen to me on my cummins WHEN lol i owned one. anything can happen on a vehicle
 

·
Registered
Joined
·
44 Posts
dodge for the most part is junk lol my .02
 

·
Premium Member
Joined
·
2,267 Posts
For the price of an allison, Your a Damn Fool To put any mechanic in a can in it! Didn't we have this conversation a few days ago?
 
1 - 20 of 25 Posts
Top