Tranny Temp issues

[jasom]

I have a 2001 chevy silverado 2500HD 6.0 4wd with 148,000 miles. I have been experiencing the tranny getting up around 200 degrees in the last 2 weeks and then it starts to shift hard. Changed the tranny fluid and filter and it still doing it only when Im hauling something. Ive been hauling the same things for several years and never had this issue. what scares me is it cold now what is it going to do when it starts getting hot again.

I'm thinking about changing the tranny cooler next. Any other ideas what might be causing it to heat up when hauling? Last week it was just a couple couches and it was very windy. I haul about 4500lbs of papers on sundays and again it was very windy. I've been hauling these papers for the last 4yrs and never had this issue.

Can I blow compressed air through the tranny cooler without damaging anything? Same with the radiator where the tranny lines go in?

Just driving down the road the temp runs around 140 to 150 shifts great. I can turn it off and let it sit for 10 min the temp come down to around 160 and it starts shifting like it should. I did add some lucas oil treatment to see if it would help and no change.

Any other ideas on what to try i would apreciate it

Thanks,
Jason

[CL8]

Maybe a bad radiator cap or thermostat?

[MagicRat]

Is it possible you have lost the lock-up function on the torque converter? A non-locking converter will build more heat than a locking one.

Also, try disconnecting both ends of the cooler at the transmission and blow compressed air through it. Don't use too much pressure, say 40 lbs. If the lines are obstructed, chances are compressed air is not the solution. Something may have collapsed internally so you need to isolate the component with the blockage and replace it.

[j cAT]

Originally Posted by jasom

I have a 2001 chevy silverado 2500HD 6.0 4wd with 148,000 miles. I have been experiencing the tranny getting up around 200 degrees in the last 2 weeks and then it starts to shift hard. Changed the tranny fluid and filter and it still doing it only when Im hauling something. Ive been hauling the same things for several years and never had this issue. what scares me is it cold now what is it going to do when it starts getting hot again.

I'm thinking about changing the tranny cooler next. Any other ideas what might be causing it to heat up when hauling? Last week it was just a couple couches and it was very windy. I haul about 4500lbs of papers on sundays and again it was very windy. I've been hauling these papers for the last 4yrs and never had this issue.

Can I blow compressed air through the tranny cooler without damaging anything? Same with the radiator where the tranny lines go in?

Just driving down the road the temp runs around 140 to 150 shifts great. I can turn it off and let it sit for 10 min the temp come down to around 160 and it starts shifting like it should. I did add some lucas oil treatment to see if it would help and no change.

Any other ideas on what to try i would apreciate it

Thanks,
Jason

if the transmission is slipping you wil get hotter fluid. when you tow/haul have you used 3rd gear only? if you tow using 4th gear this will cause damage . tow mode should be used whenever towing/hauling loads. If not the fluid will over heat and turn to acid especially if you have used dexron III fluid.

if the fluid level is too high you get air bubbles this also causes hotter fluid .

the coolant temp is normal and has not changed ? if so the transmission is damaged

[jasom]

Well call me a dumb ass then because I have used tow/haul while in 4th a few times. Now I'm not sure what the highest temp should ever get to But I know when I've been hauling in tow/haul in 4th or ever hauling the temp has never got over 160-170 at the very most except for the last week and it has been light loads. I watch it very carfully when hauling something.

Could it possible that its just not locking up and if this is the case how can it be checked and is this an easy fix? That is if I havent damaged the transmission from using tow/haul in 4th. Also is there an external modulator that puts the tranny in overdrive that could possibly going bad and not getting the tranny all the way in overdrive?

Also How can I tell what tranny I have (4L60E or 4L80E)

Thanks for your replies guys!!

[j cAT]

Originally Posted by jasom

Well call me a dumb ass then because I have used tow/haul while in 4th a few times. Now I'm not sure what the highest temp should ever get to But I know when I've been hauling in tow/haul in 4th or ever hauling the temp has never got over 160-170 at the very most except for the last week and it has been light loads. I watch it very carfully when hauling something.

Could it possible that its just not locking up and if this is the case how can it be checked and is this an easy fix? That is if I havent damaged the transmission from using tow/haul in 4th. Also is there an external modulator that puts the tranny in overdrive that could possibly going bad and not getting the tranny all the way in overdrive?

Also How can I tell what tranny I have (4L60E or 4L80E)

Thanks for your replies guys!!

since you have a 2500 you will have the 4l80 transmission.

I tow a 4500 lb 20 foot boat. I use tow mode and operate in 3rd gear and keep the speed to 65MPH max. when towing or not the temp of the engine locks in at 190 deg f. the thermostat is an OEM spec of 186 deg f.

if the transmission is slipping the temp will rise. also the shifting should be harsher because the pcm /computer should react to this and command higher pressure. having this dash tranny temp guage gives early warning of transmission problems. I woulld have a transmission shop check out the pressure and pull the drivetrain codes to help find what the issue is.

post back what was found and how corrected good luck.

[Awake79]

I have the same problem, with my tranny heating up for no reason that I can find? I have an '05 2500HD, and and I tow my travel trailer with it, and ever had any issues. Then last summer it just started heating up to the the range it would be at when I tow, but that would only be while driving arouund town, or to and from work. I think it may be something a shop did; I had the u-joints replaced, and it was only after then that is started happening. Could there have been something with the u-joints not being properly installed that would lead to the tranny getting hot?

[j cAT]

Originally Posted by Awake79

I have the same problem, with my tranny heating up for no reason that I can find? I have an '05 2500HD, and and I tow my travel trailer with it, and ever had any issues. Then last summer it just started heating up to the the range it would be at when I tow, but that would only be while driving arouund town, or to and from work. I think it may be something a shop did; I had the u-joints replaced, and it was only after then that is started happening. Could there have been something with the u-joints not being properly installed that would lead to the tranny getting hot?

u joint will cause vibs if not properly done .

transmission is slipping . this is causing the heat. the temp guage is a warning tool to alert you to take the proper actions.

what fluid has been used with this ? how often is the pan droped and filter/fluid replaced ?

if your not doing this every 30,ooomi and you tow/haul , with the dexron III this is what happens.

[Awake79]

Well sh!t...I have never had the tranny serviced. When I looked at the manual it only recommends at 100,000 miles, so I figured I was good. The truck is coming up on 80,000 miles, and I've only put 30,000 on it in the 3+ years I've had it. I have a road trip coming up, so I had intended on doing it early anyways, with the hopes that some fresh fluid would help the problem. And, as far as I know its the originial fluid in there.

[ricebike]

When I looked at the manual it only recommends at 100,000 miles, so I figured I was good.

that's under "normal" conditions

towing stuff from time to time should fall under "severe" conditions... what does it say under that schedule?

pull the dipstick and see if it's still pinkish, not brown/burnt...

[Awake79]

Well, I didn't think hauling my camper once a month or so during the summers would have put me into that category, but I'll check it changed right away. I don't have the manual in front of me, but if I recall correctly it was 75,000 for the "severe" conditions category. I don't have any hard shirts, or vibrations coming from the tranny, seems to be fine other than the, what I seem to think, is uneccesary heating up.

[j cAT]

Originally Posted by Awake79

Well, I didn't think hauling my camper once a month or so during the summers would have put me into that category, but I'll check it changed right away. I don't have the manual in front of me, but if I recall correctly it was 75,000 for the "severe" conditions category. I don't have any hard shirts, or vibrations coming from the tranny, seems to be fine other than the, what I seem to think, is uneccesary heating up.

100,ooomi is the light duty fluid interval change . that means no towing ,no loads,no hills,no stop and go stuff,no 90deg f temps. basicly this 100,ooomi interval is GM BS .

the 30-40,ooo mi interval is real world stuff.

the first fluid change is the worst. lots of dirt in most cases.

then you got drive train fluids the rear/front diff needs replacing same interval .. transfercase you change when it starts to get dark/blue gray color. these are checked at the oil servicing .

[Awake79]

Well damn...definitely will be getting some service done. You guys think that is something for dealership, or any old quicky-lube joint can service my tranny and the differentials? I usually get my oil done at a drive-thru joint, but there is a little mechanic shop I've taken my truck to for some stuff in the past, and I think they do lube work as well? Sorry, just not to smart in the service area, thats why I joined the forum! lol. Sorry jasom, didn't mean to hijack your thread with my own problems.

[j cAT]

Originally Posted by Awake79

Well damn...definitely will be getting some service done. You guys think that is something for dealership, or any old quicky-lube joint can service my tranny and the differentials? I usually get my oil done at a drive-thru joint, but there is a little mechanic shop I've taken my truck to for some stuff in the past, and I think they do lube work as well? Sorry, just not to smart in the service area, thats why I joined the forum! lol. Sorry jasom, didn't mean to hijack your thread with my own problems.

have a well recommended local repair shop do this servicing. make sure they use the proper fluids. have the rear diff cover removed and cleaned out, especially the magnet. transmission pan needs removal and cleaned out as well also magnet.

transfercase needs tracII gm blue fluid. transmission dexronVI. rear diff is the 75-90wt mobil synthetic gear lube.

front diff takes 80-90wt gl5 gear lube.

quick lube shops are not the place to go for proper fluid replacing proceedures.

do not have anyone power flush out the transmission on this vehicle. the loosened particles will kill it.

[GMCustomerService]

Originally Posted by Awake79

Well, I didn't think hauling my camper once a month or so during the summers would have put me into that category, but I'll check it changed right away. I don't have the manual in front of me, but if I recall correctly it was 75,000 for the "severe" conditions category. I don't have any hard shirts, or vibrations coming from the tranny, seems to be fine other than the, what I seem to think, is uneccesary heating up.

You're already receiving some great advice; I just wanted to clarify some owner's manual information for you!

The first recommended transmission fluid change for vehicles in "severe" service is at 50,000 miles. It is recommended to change the fluid fluid and filter if the
vehicle GVWR is over 8600 lbs or if the vehicle is
mainly driven under one or more of these conditions:
− In heavy city traffic where the outside temperature
regularly reaches 90°F (32°C) or higher.
− In hilly or mountainous terrain.
− When doing frequent trailer towing.
− Uses such as found in taxi, police or delivery
service.

Hope this is helpful!
Sarah
GM Customer Service