GMC work truck

Shorty

Rusty Nut
Senior Member
So I am running a 2007 GMC for work. But lately, it doesn't want to work as much as I do. The trans keeps overheating for me. Maybe a 20 minute drive will peg the heat gauge. I am thinking that there is a slight chance a coolant line is restricted. Or the pressure regulator is worn. Or the entire thing is a ticking time bomb ready to drop a million pieces on the road leaving me to hitchhike back home. I had it flushed about 12,000 miles ago so that shouldn't be part of the issue. Any experience on this?
 

KennyP

Alice's Creator
Staff member
Moderator
Senior Member
My son told me that was an issue with 4l60e's. He has a 2009 Yukon, went down and bought the largest tranny cooler he could find for his. Took a trip to Florida with it and the tranny never got up to normal most of the way.
 

Ryan313

Tractorologist
Senior Member
Member
How old was the fluid before the flush? Supposedly, if your fluid is beyond it’s useful life the detergent in the fluid no longer cleans, and the Tranny starts to get caked up. When you put new fluid in it, the new fluid with working detergents breaks everything loose and causes it to clog.
 

MFDAC

Tractorologist
Senior Member
Member
Thanks for updating this thread, Shorty, I missed the first post. I will keep this in mind for my wife's '06 Denali! Tranny was flushed about 2 years ago, and the only time I've noticed the gauge about half way hot was driving on some slow mountain roads in the Rockies---so far!

DAC
 

Shorty

Rusty Nut
Senior Member
Trams oil clogging a cooler is odd. What kind of chunks are floating around in there?
Way too big!
How old was the fluid before the flush? Supposedly, if your fluid is beyond it’s useful life the detergent in the fluid no longer cleans, and the Tranny starts to get caked up. When you put new fluid in it, the new fluid with working detergents breaks everything loose and causes it to clog.
Probably was mostly original, had a slight leak that we had to add. So about 210,000 to the first flush. Then 12,000 to the second flush. What you said sounds likely what happened.
 

olcowhand

Daniel In KY
Staff member
Administrator
My old 97 Ford F250 with the tiny stock trans cooler would overheat with hardly any load on really hot days and puke oil by the gallon out the vent. I made a cooler out of an AC condenser out of a 98 Grand Cherokee Jeep. Mounted it in front of the radiator and NEVER had any overheating issues afterwards, no matter how large a load I pulled. This condenser had 3/4 the area as my truck's radiator.
 

JBRamsey

Tractorologist
Senior Member
Member
How old was the fluid before the flush? Supposedly, if your fluid is beyond it’s useful life the detergent in the fluid no longer cleans, and the Tranny starts to get caked up. When you put new fluid in it, the new fluid with working detergents breaks everything loose and causes it to clog.
I've always heard if you have an automatic that has never been serviced with a lot of miles to not service it. Just keep it topped up and don't change the fluid and filter.
 

Cvans

Tractorologist
Senior Member
Member
One was change oil n filter, but not a power flush at that point.
I like the sounds of this one. A lady at work was telling me they were going to have to purchase a new car because the tranny in their car was acting up. Slow to go into gear when cold. I suggested they change the oil and filter first. They didn't know you could do that. Things worked fine afterwards.
 

Rustyoldjunk

Rustologist/Punishment Glutton
Senior Member
Member
My 95 Ram 1500 has 2 coolers. One in the radiator and a second in front of the radiator.
The pretty much original owner,who I bought it from,bought it in 96,less than a year old.
He used it to pull his 5th wheel RV. Along with 5th wheel hitch and trailer brakes,he added extra rear springs and a second cooler.
The truck has almost 290,000 miles miles and runs and shifts like new.
It probably doesn't have it's original engine or trans or it might,I don't know. I do know that anything went wrong with it he took it to the dealer and spent the money on it.
I have have drove it probably close to 40,000 miles the last few years.
Pulled a lot of heavy trailers with it and or heavy bed loads.
The transmission still shifts as crisp as new.
I do also use Lucas transmission conditioner in it and all my older automatic vehicles.
 

chieffan

Tractorologist
Senior Member
Member
Lucas is a good product line for sure. When I put power steering on a IH400 tractor I used a Charlyn steering unit and a Chevy truck pump. Working it in hot weather loading 8 small sqrares at a time would slow the steering down considerably. Lucas Hydraulic oil treatment and asmall cooler in front of the radiator took care of that issue. Had to use it in the hydraulics of the accumulator to keep it working up to speed also.
 
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