Transmission Running Hot
 

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:D

Re: Transmission Running Hot
 

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.

Re: Transmission Running Hot
 

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.

Re: Transmission Running Hot
 

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):D

Re: Transmission Running Hot
 

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

Re: Transmission Running Hot
 

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.

Re: Transmission Running Hot
 

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: Transmission Running Hot
 

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.

Re: Transmission Running Hot
 

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.

Re: Transmission Running Hot
 

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.

Re: Transmission Running Hot
 

Heres one for you and there are others..

Re: Transmission Running Hot
 

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.

Re: Transmission Running Hot
 

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.

Re: Transmission Running Hot
 

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?

Re: Transmission Running Hot
 

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.

Re: Transmission Running Hot
 

dont ask me to help, but no just operating temp., and check in park.

Re: Transmission Running Hot
 

you can attach any fan to the cooler (pusher or Puller)depending on mounting and location conditions.

Re: Transmission Running Hot
 

I would fashion a heat shield over the exhaust crossover first, before I did anything else. The radiant heat could simply be cooking the bottom of the tranny pan when working hard as your exhaust temps would be running higher than a stock rig would and that would show up on an extended grade climb. Cheap and easy that might just help.

Re: Transmission Running Hot
 

on the dipstick it says check level while parked and ideling. Ok done.

The level while not apparent in the pictures was between the two holes on the stick, the color seams ok. It's not supposed to be clear is it? It doesn't smell burnt.

Re: Transmission Running Hot
 

I'm pretty sure nothing else is going to fit infront of the radiator.

Re: Transmission Running Hot
 

dropping the trans pan will not be a problem as the exhaust is well out of the way. There is about 5 inches between the under body protection and the pan

Re: Transmission Running Hot
 

here are shots of the supply lines for the atf.

Re: Transmission Running Hot
 

there doesn't appear to be anything leaking and the trans fluid level seams to be ok.

I'm having a new AC unit installed in the house today so will not be able to take the truck to the dealership. I'll get to it and let you know what if anything they have to say or suggest.

The dealership that did the trans service is in Ca not practicle for me to get back to so I'll try my local dealership and see if they'll cover taking a look at the trans under warranty.

Thanks again to all of you for your suggestions.

Re: Transmission Running Hot
 

Paragon, thanks. I can see in this pic exactly what you mean. The exhaust is pretty close to the pan.

Re: Transmission Running Hot
 

The "blotter test" sounds interesting. Now thats a new one on me. Sounds like the sticky lifters and the quart of transmission fluid to unstick the lifters trick. Mabee a check with the amsol and 25 dollars will give more exact information. Not to say it dont work, its just new to me. I would like to know more about that suggestion though. But thanks Phil, I recieved everything! From the looks of the pics I dont see evidence of the pan being removed. Mabee a few pressure checks might reveal something, but again I think a trusted transmission performance shop might shed more light on the situation. FWIW My exhaust is in the same location and you stated the engine temp is normal right? If you cant trust the shop do the show me the money and ask to see it in some form of publication and verify what they are doing. If they dont want to do it then take it eslewhere.

Re: Transmission Running Hot
 

That's a good one Phil, I need to keep that one in mind.:)

Re: Transmission Running Hot
 

Phil, For the cost of transmission fluid I know what I would do! I totally agree with you. I think this problem needs more checks done. pressures and bands and new filter and oil changed. Mabee its worth it if it saves the transmission.

Re: Transmission Running Hot
 

Quote: H2 Ranger (FWIW My exhaust is in the same location and you stated the engine temp is normal right? )

Yes the engine temp stayed within it's normal range, while the trans displayed "Trans Hot" on the center console. By normal range I mean when the trans was at it's hottest the engine coolant never got more than the width of the needle above 210 however 185 is normal for my truck now with the 160 t-stat, so the engine coolant was affected by the hot trans.

However lets keep in mind my truck is far from "normal or stock" the S/C produces more heat, thats a given, a combination of a larger radiator, new high flow catalytic converters and 160-t-stat seam to have fixed the engine coolant run hot issue.

Depending on who you talk to about my previous run hot condition with the motor most are pointing to the catalytic converters being plugged and a continuing leaning condition being brought on by 1-3 clogged or partially plugged fuel injectors.

After having the passenger side head replaced because a valve guide got sucked into the head due to the motor running too lean and getting too hot on too many occasions, (although I argue the point too many) it was exactly 3 occasions and never driven for long under excessive heat but I guess that was enough to cause the problem. Having replaced the catalytic converts with higher or free flowing ones I probably could have gotten away with not going to the expense of changing the radiator or changing the t-stat, but it's done now and engine wise seams to be working correctly.

I don't think any one thing caused my truck to run hot. I think it's been a lot of things combined.

I'm just hoping the problem with the trans is easier to realize and solve.

Starting with a larger pan which will hold more fluid and a larger trans cooler if a place to locate it can be found I'm hopeful whatever is happening with the trans will be resolved.

The trans shifts fine, the trans operates at normal operating temps with city stop/go driving. There is no apparent slippage so I don't think anything internal is wrong, it's just getting too hot on steep or prolonged hill climbs.

Thanks again guys for all the suggestions:D

Re: Transmission Running Hot
 

Completely accurate. It's a test that's used when evaluating oils and fluids for oxidation and breakdown. The blotter test lets you know that the fluid still flows because it spreads through the paper. If it is oxidized and gunked up, it will sit and not spread very much. They test how long fluids can sit at certain temperatures (mainly engine oil, tranny fluid, gear oil) to make sure it can not break down under extended use at XXX temperature.

Re: Transmission Running Hot
 

Learn more every day and even more researching. Little more to the story than whats said:

http://www.practicingoilanalysis.com/article_detail.asp?articleid=355&relatedbookgroup= OilAnalysis

Re: Transmission Running Hot
 

did'nt read the entire post but if your trans is getin hot enough to throw A warning(not just by the gauge) and your not towing you have an issue. New trucks should handle any environment without issue when left stock. Adding A supercharger will not affect trans temp unless you really work it up A steep grade with A lot of added weight as any H-2 will drop to 3rd and no tcc lock up while climbing A long grade. If you are towing and remove the trailer your trans shift adapts take A little while to adapt but should still not cause A heat concern. Have it checked out while under warranty even if it costs A few bucks, at least they have your concern on record if it fails 10k miles out of warranty.