Transmission Running Hot

[Fubar]

Hi all; if it's not one problem it's another At least it seams that way for me lately.

Here's my current concern; while climbing long grades or steep mountain passes my trans gets hot to the point where "Transmission Hot" appears on the center console.

I know simply pulling over and leaving it in park and letting the motor run for 10-15 minutes brings everything back to normal. It's just a pain..

But considering I'm not towing anything and the trans is reaching this "Too Hot" condition, I'm wondering if getting a larger trans pan, one that will hold an additional 3 quarts if this would solve this problem?

I guess a larger trans cooler might also help but with my recent past engine running hot issue, which I can happily say has been solved, anyway with this past trouble in mind I don't really want to stack something else in front of the new radiator.

So would something like this work? It say it supports up to yr 02 and the list of trans that it says it will fit doesn't list the one in the Hummer (Hydra-Matic 4L65-E).

http://www.xtremediesel.com/index.as...PROD&ProdID=29

Thanks in advance for any suggestions

[H2 Ranger]

Check some of the racing parts suppliers, they have many configurations as it pertains to Transmission coolers. Some offer remote cooling fans and alternate mounting locations, additonal remote filters, larger oil supply lines, etc. Anything that give addition oil supply and cooling area mass will help. Hope you get it resolved.

[MarineHawk]

Is this normal? Or is something wrong with the tranny? Also, do you have the two/haul mode thingy? Would it help? Mine shifts higher and more sharply in the tow haul mode.

[Fubar]

Thanks guys.
Adding a larger radiator that holds 2-3 extra gallons along with adding a couple additional rows of cooling fins solved my run hot issue with the motor/supercharger. Even though the trans got hot the engine coolant remained at or below 210 which is normal for the H2.

So I was just hoping that by adding a larger pan to the trans that the same would hold true for that system.

I'll continue looking at options.

Just running around town there's never any problem with the trans getting hot but it seams that when its under any prolonged stress/load and the temp continues to climb. I would expect the temps to climb if I was towing anything but I wasn't.

The trans was just serviced in April. I'm guessing they pulled the pan changed the filter and re-filled it with oil. I'll check to make sure they actually filled it.

As for the tow/haul button, good question. I don't know I've never used it, it is there. The trans was not hunting or shifting as I was going up the grade. 2000rpm's 60-70-mph I wouldn't think that would be too much for the truck.

On the my trip to Big Bear 8200 feet up and doing 20-mph up windy roads I kind of expected to see the trans temp raise just not as high as they did.

What concerned me most was on the way home from Ca there are two 5000-ft passes spanning 25 miles 16 miles on one and 9 miles of climb on the second or may it's reversed either way near the top of the second pass the trans got to the point where I needed to pull over. Outside air temps were 80-85 not what I would consider a problem.

I'm rambling... Thanks again for the suggestions.

I see an F250-F350 in my future (possibly)

[Fubar]

Phil,
wouldn't adding an additional tranny cooler possibly make the trans run too cool most of the time under normal day to day driving and possibly cause a problem of its own?

I've been told that if you make the front part or one part of the trans too cool the back end or other part has to work extra hard to make up the temp difference. I don't know anything about trans or how they work so this may be complete b/s..

Adding a trans cooler seams like it would be the lesser complicated or cheaper way to go.

Thanks

[Fubar]

Phil,
looking at your pictures of your install of the Hayden Ultra Cool I can't install the unit in the same place due to the fact that the innner cooler for the S/C is currently there. I have no doubts that installing a trans cooler where you have it would reslut in much cooler trans temps.

The other possibility might be to place the additional trans cooler in front of the radiator and put a fan on it to make up for the lack of air coming threw the front grill.

[H2 Ranger]

Has the overheating been since the vehicle was new? or has it started since service?

If its been that way since service:
1. Maybe the bands were adjusted too tight thus causing excessive friction.
2. Is the pick-up filter properly installed?
3. Is there any line restriction including bent or twisted lines?


Seems like you might have noticed it earlier if its been overheating. Additional cooling and or fluid capasity is always a good route to go.

[RIC-H0]

If it's still under warranty, I would definetly take it in. Mine actually started overheating the same way, and then it went out about a month later.
Got a newly rebuilt factory trans, and never had that problem again.
Have you checked your trans fluid lately? I'm sure it's black by now if it's overheat so many times. Either way, I would change out your trans fluid.

[Fubar]

Originally Posted by H2 Ranger

Has the overheating been since the vehicle was new? or has it started since service?

If its been that way since service:
1. Maybe the bands were adjusted too tight thus causing excessive friction.
2. Is the pick-up filter properly installed?
3. Is there any line restriction including bent or twisted lines?


Seems like you might have noticed it earlier if its been overheating. Additional cooling and or fluid capasity is always a good route to go.

RE: 1, anything is possible but the trans remains at it's normal operating temp most of the time. It only climbs when going up long or steep grades.

RE: 2, I haven't a clue. With the other stuff the the tech from Cerriots Hummer f u c k e d up I wouldn't be surprised to find that he's messed up the filter install as well.

RE:3 No there are no bent or twisted lines. The only two lines I see are both 1/2-3/4 inch coper for the incoming and return of the ATF from the radiator back to the trans.

It's only 90 this morning at 7:30 I'll go out and crawl around and see if anything jumps out at me as being wrong..

Thanks for the list of stuff to check.

[Fubar]

Phil,
Thanks for all the advice.

I need to find a mechanic here in town I can trust and that is proving to be difficult.

[H2 Ranger]

Heres one for you and there are others..

[Fubar]

Ric,
Thanks, I'll check with the dealership and see if they would be willing to check the condition of the trans under warranty.

It will not come as a surprise to me if they tell me that because of the supercharger I had them install that my trans is no longer covered.

The trans fluid was changed in mid April along with having trans maintenance done. this was done when the truck broke down due to a valve guide that got sucked into one of the heads while on my to Ca for a visit to my folks. The heads and exhaust had to come off anyway so I told them to service the trans.

[Fubar]

H2Ranger, ya I was looking at those on-line last night. I'm just a little leary of anything made by flex-a-lite because of the troubles I've had in the past with there fans. In all fareness the fans were probably just fine it was just a crapy job of installing the control module that I believe caused my past problems with the fans.

Thanks though I will continue to look that option and others.

Originally Posted by H2 Ranger

Heres one for you and there are others..

[Fubar]

question; does the truck need to be in drive when the trans fluid level is being checked? I mean do I need to tackel a neighbor and ask for help with checking the fluid level or will placing the truck in park and letting it get up to operating temp work?

[H2 Ranger]

If this condition has started since service, Have them reacheck the adjustments something is not right. Mine has a SC too and I dont have such conditions but mabee someday.... But in Heat regard such has Phil indicated it can be many things Slippage of clutches, lubrication restriction, fluid condition, etc. Do you have a good performance Transmission shop in the area? And a good aftermarket cooler would definitly help. I really dont think you will run into a condition (UNLESS YOU LIVE IN THE ARTIC) where you will need to worry about low transmission tempature. The higher the temp the more friction. Let us know the outcome.