Tranny Temp issues

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

Maybe a bad radiator cap or thermostat?

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.

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

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!!

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.

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?

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.

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.

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...

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.

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 .

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.

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.

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

Ok I had the transmission checked a couple of weeks ago and no codes. I now keep the tranny in 3rd when hauling no issues on over heating. It doesnt even get to 150.

Now heres another kicker Last night I got home and noticed some tranny fluid on the floor. I got under it and there was tranny fluid all the way from transfer case to the rear end. Its was being pushed out what I would call the vent hose. It goes from the top of the tranny back to the top of the transfer case. When I pulled the hose down tranny fluid started coming out of it. So what is this hose and what would make it start pushing out that hose? No its not overfilled.

Ok I had the transmission checked a couple of weeks ago and no codes. I now keep the tranny in 3rd when hauling no issues on over heating. It doesnt even get to 150.

Now heres another kicker Last night I got home and noticed some tranny fluid on the floor. I got under it and there was tranny fluid all the way from transfer case to the rear end. Its was being pushed out what I would call the vent hose. It goes from the top of the tranny back to the top of the transfer case. When I pulled the hose down tranny fluid started coming out of it. So what is this hose and what would make it start pushing out that hose? No its not overfilled.

check the fluid of the transmission and transfercase for proper levels. seals can leak causing tranny fluid to go into the transfercase or the other way .

see how towing in the proper gear in tow mode reduces the temp . this is why most transmissions get cooked . high gear with the torque converter locked towing gets the tranny super hot. dexron III becomes acid.

All levels are correct in transfer case and tranny. Tranny fluid is getting a little lower since it keeps blowing out the vent hose.

I was reading a repair manual and it said when fluid comes out of the fill tube or vent pipe this could be caused from Overfilled( wich is not it) Coolant in fluid (wich is not it) Wrong dipstick(wich is not it) The vent is plugged(checked it, this is not it) The case is porous(not sure how this would push fluid out a vent hose) DRAIN BACK HOLES PLUGGED( This could be it)

Now can anyone tell me where the drain back holes are and How I can unplugg them if they are plugged.

I am sure you know all this I am going to explain / justmaking sure .

with the vehicle on level ground checking always at the same parking spot with vehicle at operating temp / driven 10 miles shift lever in park, engine at idle, the fluid level should be just below the fill mark by 1/8 inch.

the fluid will have no air bubbles in it. it should be a solid red color.

the dip stick level can be very difficult to read with clean fluid.using a cloth wipe down the stick. repeat checking until your sure it reads at the same point on stick.

if its over the full use a qt, container hand pump with a 3/8 plastic tubing on the suck end , and slide down the dip stick tube to start sucking the fluid out.

you won't believe how many do this wrong.

Went out today to check things over again. Tranny fluid is at correct level and I had to add 24oz since its been blowing out the vent hose. I got to thinking about it and maybe I'm wrong. If the drain back holes were plugged I would think there would be a big puddle of tranny fluid under the truck from pushing out the vent hose while sitting there.

It only seems to be pushing out while driving down the highway. So at this point I'm I have no other ideas to go on. So if anyone has anymore ideas please feel free to shoot them at me.

Also do you know where the drain back holes are in the tranny?

Went out today to check things over again. Tranny fluid is at correct level and I had to add 24oz since its been blowing out the vent hose. I got to thinking about it and maybe I'm wrong. If the drain back holes were plugged I would think there would be a big puddle of tranny fluid under the truck from pushing out the vent hose while sitting there.

It only seems to be pushing out while driving down the highway. So at this point I'm I have no other ideas to go on. So if anyone has anymore ideas please feel free to shoot them at me.

Also do you know where the drain back holes are in the tranny?

when your adding fluid and as this last time you added 24 oz. you should not see any fluid on the stick !

drain back hole would be from the radiator to the transmission after its cooled down. if that were restricted that would cause transmission to heat up.

blowing out the vent is from overheating or too much fluid.

with the fluid at the correct level and engine hot go for a 1 mile drive then recheck the fluid for level and air bubbles on stick.

when your adding fluid and as this last time you added 24 oz. you should not see any fluid on the stick !

drain back hole would be from the radiator to the transmission after its cooled down. if that were restricted that would cause transmission to heat up.

blowing out the vent is from overheating or too much fluid.

with the fluid at the correct level and engine hot go for a 1 mile drive then recheck the fluid for level and air bubbles on stick.


Ok just drove 70 miles and it didnt leak a drop of tranny fluid go figure. Dont know why its done it all week then tonight nothing. Now it is around 10 degrees here tonight where it has been around 40 all week. The tranny temp though has been the same around 145 to 150.

As for there being no oil on the dip stick when adding the 24oz there was a little on it. It calls for a pint just to fill it between the hatch marks.

I'll keep an eye on it all week and I'll get back with you on my findings. Thanks for your help and answering my questions!!!

Now it is around 10 degrees here tonight where it has been around 40 all week. The tranny temp though has been the same around 145 to 150.

.

I'll keep an eye on it all week and I'll get back with you on my findings. Thanks for your help and answering my questions!!!

the 10deg f temps will keep the temps down. just the body of the transmission will reduce the temperature. actually the radiator will add heat to the transmission at low temps like this. this is a good thing because if the fluid is too cold that is also not good.

I would say 150 deg f is a good range over 200 deg f is not.

I would say 150 deg f is a good range over 200 deg f is not.


Really? Sorry to bring the topic back, but I've been without a computer for a couple weeks. My temp gauge used to rest at 100, not even go up when I drove around, just normal driving. And when I would haul my travel trailer it would get up to 150. Now my daily driving is getting me up to 120-140, but this is an acceptable range?

Really? Sorry to bring the topic back, but I've been without a computer for a couple weeks. My temp gauge used to rest at 100, not even go up when I drove around, just normal driving. And when I would haul my travel trailer it would get up to 150. Now my daily driving is getting me up to 120-140, but this is an acceptable range?


the radiator adds heat to the transmission fluid in cold weather. in hot weather it removes heat from the fluid. 150 deg f at hywy speed at a 50 degf air temp would be normal. the faster you go /greater the load , the larger the heat load.

if the fluid temp stays below 100 degf then the guage must be off. another reason is having an external transmission cooler mounted in front of the ac condenser. this would drop the transmission temp to a lower than normal level especially in cold winter temps.

200 deg f fluid temp starts the fluid breakdown. this causes transmission wear/damage.

too cold a fluid the flow is affected. synthetic transmission fluids do indeed reduce this effect at cold temps.

synthetic fluids do conduct heat much better to reduce operating internal temp.

if you have a below 100degf temp reading I would not believe that the guage was connected or working.

Well after the tranny starting to heat up again we put it on diagnostic machine. The pump was bleeding so were putting in a new jasper tranny next week.