Transmission Running Hot

[Fubar]

Originally Posted by HUMTECH

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.

Ya the issue is lack of air getting to the trans cooler caused mostly because of the inner-cooler for the S/C blocking 2/3rds of the front gril. So one of two things needs to happen; get more air to the trans cooler which isn't possible due to lack of space to mount a fan anywhere or locate a secondary cooler somewhere else under the truck with a fan and two thermal dynamics dictates that if you add more fluid you increase the ability to dissipate heat, add more fluid or increase the surface area said fluid transverses and both will reduce heat.

Enough to make a difference I don't know. But I have to start some place.

If there was actually something mechanically wrong with the trans the run hot condition would be present in day to day driving and not only when climbing steep or prolonged grades. However the truck never downshifts while going up the two passes between here and CA. I've always figured it was because there is now ample power being produced by the sc so that the trans doesn't need to hunt for a gear to help move the weight of the truck. The trans will downshift if I floor it (3000-3500rpms) going up the grade. But keep the rpms around 2000 and it never downshifts.

Here's some food for thought; from Vegas to Moab 400+ miles there is a 9000 foot pass that you go over and the truck has never over heated going up that pass. Between Vegas and Ca there are two 4000ft passes and on each and every trip I've made since having the SC installed two years ago April the trucks trans has gotten hot. I don't get it.. It has to have something to do with the grade % and the length and the reduded air flow to the cooler.

I'll check with my local dealership but I'm almost certain they are going to say the trans is not covered by warranty becasue of the supercharger.

[KenP]

Originally Posted by PhilD

Not sure how much difference a bigger tranny pan will make, but a fonned pan will help a little. You'll have to remove the exhaust to replace it, and some of the deeper ones will not fit because of the exhaust location, so make sure you measure first. That seems pretty expensive also.

I added an additional tranny cooler it made a quite a difference;

http://www.*******club.com/tech/tranny_cooler.html

If you are concerned about redicing flow to the main rad, you could mount one somewhere else and have a fan for it. I think someone else did that ?

Great write-up Phil. I thought of your problem when I read Fubar's post.

[KenP]

Fubar, FWIW, our old truck NEVER got hot. Even during the VA Beach to Moab run. Heck, our new truck doesn't get hot either. Somethin's rong, brotha.

Find a place to mount a 4 pass trans cooler in front. Look hard, I know there's space. That'll solve your problem.

Keep us updated, buddy.

[Fubar]

Ken thanks.
mount a trans cooler up front, where?

there are 3 coolers stacked (4) if you count the inncooler for the s/c in front of the radiator.

The 3rd in line or 2nd largest I'm guessing is the current trans cooler, don't know what the other two are.

Perhaps if the front most one bracketed by the black braces can be relocated a new or additional trans cooler could go in it's place. ?

[H2 Ranger]

Check out this article talking about xsmn cooling;

http://www.carcraft.com/techarticles/116_0308_cool/


Also consider the following mods:

Shiftplus electronic Improver kit

Shift improver kit (for valve body)

both from B&M

Both of these kit reduce slippage and heat buildup

[drmiles]

Fubar, I have 05 with the SC, and a 10,000lb trailer. Not many hills here but we do have 100+ days. Transmission has never run hot!! I use Royal purple Synthetic. My 03 Tranny ran hot just before 2nd and 4th gears failed!!!

[Fubar]

Originally Posted by H2 Ranger

Check out this article talking about xsmn cooling;

http://www.carcraft.com/techarticles/116_0308_cool/


Also consider the following mods:

Shiftplus electronic Improver kit

Shift improver kit (for valve body)

both from B&M

Both of these kit reduce slippage and heat buildup

Ranger thanks for the info and the suggestions. The article was informative and I'm seeing that there are options out there. I just need to find a quality repair shop here in town. Thanks again.

[Fubar]

Originally Posted by drmiles

Fubar, I have 05 with the SC, and a 10,000lb trailer. Not many hills here but we do have 100+ days. Transmission has never run hot!! I use Royal purple Synthetic. My 03 Tranny ran hot just before 2nd and 4th gears failed!!!

Well that sucks. Define or explain for me if you can exactly what was happening when your trans ran hot before you suffered gear failure. Were you towing your trailer, climbing mountain passes I mean really working the trans? Or was it getting hot during normal day to day use?

I'm thinking my simplest short term solution is reduce the number of trips I make in the H2 to Ca since it's on that route that the trans seams to be having its issues. Driving around town the trans has yet to get hot. I have something else to drive so not taking the H2 to CA isn't a big deal. It's an inconvience but not a big deal.

I'll continue looking for a qualified shop here in town. I agree with all of you that I have some kind of problem with my trans.

But it's kind of like going to the doctor, you get there and whatever was bothering you enough to go in the first place refuses to surface while you're there and you end up asking the doc to fix something he can't see is broke...

Vegas is flat there is a 9000ft pass going North on I-15 toward I-70 which has yet to cause a problem for the trans and then the two 4000ft passes on the way to Ca. Getting to any of these is a 2-4hr journey which is a bit much to ask a mechanic to commit to in an attempt to duplicate the problem. What I've heard from a couple places I've been to is drive it till something breaks.. Ahhh NO I don't think so. Needless to say both those shops lost any potential bussiness I may have brought there way. I'm about frustrated enough to put the H2 on a flat bed and have it towed to HGW.

[kodiakz]

Damn!! I just started having the exact same issues with the same setup. I can run around town and not have any problems. The minute I go up a little pass, both motor and tranny heat way up very quickly. I do believe that it could have something to do with the intercooler's heat exchanger blocking the other coolers. I also might look into the idea of putting in a heat sheild since that left with the stock exhaust. I also noticed that the engine temp will immediatley jump to 220-230 range if I run the ac on a hot day. I have had many other s/c gm motors and they never ran hot like this one.

Fubar, what size radiator did you put in and has that completely solved your motor temp issues?

What do you guys think about putting in some sort of slotted insert in place of the black plastic one in the hood for more air intake? I think I saw one on an H2, but if I remember correctly, it looked like a retarded scoop Does the programming done to the pcm affect the temps at all? I know that the programming for the shift points/firmness could affect that side of things but what about motor temps?

[Fubar]

Kodiakz,
I'll have to check with the shop that did the install of the radiator for the size. I know it holds 3 extra gallons and I believe was 2 inches thicker then the stock unit. I know the radiator would not work with the H2's stock clutch fan in place it barley fits with the electric fans.

I would think that any quality radiator shop should be able to get one for you or have one made. It is made out of the same material as the stock unit it's just deeper/thicker. I can tell you although just my personal opinion backed with some research and personal observations, to stay away from aluminum radiators.

I'm still considering a deeper trans pan:
http://www.maghytec.com/index.asp?Pa...ATS&Category=3

I still need to get a hold of them to verify if the pan they are offering will fit the model of trans in the H2. The "Hydra-Matic 4L65-E" is not listed as a trans that their pan will fit on.

I also looking at one or two additional trans coolers to be placed in the front grill next to the inner-cooler for the s/c but the available space is only 8x8.5 so I'm not certain I can find anything to fit that space, then there is the further reduced air flow to consider by adding anything to the front grill area.

Removing the existing trans cooler and replacing it with something larger seams like the most do-able option but I'm still researching.

[Fubar]

Oh and on my recent trip to ca (last weekend) the engine coolant never got above normal 210 even though the air outside was 100-110 in places. So I'm pretty sure the larger radiator has solved my engine cooling problems. Even while climbing the mountain passess with the a/c on the engine temp never got above normal. The trans on the other hand... well thats another story. I had to pull over twice and sit with the trans in park for 10-15 minutes till it came back down within its normal range. And yes going threw Death Valley at or around midnight it was still hot as h.e.l.l.

[kodiakz]

"I had to pull over twice and sit with the trans in park for 10-15 minutes till it came back down within its normal range"

How many times can you do that without damaging the tranny??

[Fubar]

Originally Posted by kodiakz

"I had to pull over twice and sit with the trans in park for 10-15 minutes till it came back down within its normal range"

How many times can you do that without damaging the tranny??

don't know. keep an eye on the trans fluid I guess. Hopefully I'll get the issue fixed before it becomes a larger problem.

[kodiakz]

Did you try Magnusun tech line and see if they have any suggestions or have run into this issue? May give them a jingle tomorrow and hope they have a solution.

[Fubar]

good luck.
they will probably tell you to get a Ron Davis aluminum radiator. Don't do it.. find another option.

I'd have your trans checked by a qualified mech to make sure there is nothing actually wrong with it. If he says it's ok then get a trans cooler and a deeper trans pan.

I spoke the folks at Mag-hytec today (jerry) 818-786-8325
http://www.maghytec.com/index.asp?Pa...ATS&Category=3

The pan will fit our transmissions. just make sure you've got more then 4 1/2 inches between the exhaust cross over pipe and the flange where the pan bolts to the bottom of the trans.

If not then get a trans cooler at the very least.

Personally I'd have someone route the trans fluid lines out of the radiator and plug the holes. Leaving the stock trans cooler in line will probably be a good thing just add a secondary cooler.

[Fubar]

http://www.thermotec.com/products/full/11600/11600.html

It was also suggested to me today to look into this. especially if a deeper trans pan is used.

[H2 Ranger]

I have read a lot about transmissions lately and would like to make some Preventive Maintenance suggestions that might help concerning overheating:
Transmission temp: a Lead Builder says 175 degrees. Another says Transmission lasts longest 175 degrees.
Excessive heat can cause the oil to break down: Leads to varnishing of internal parts, from the burnt oil, provides more resistance to internal bearing and clutch surfaces, Clutch material becomes softer and more prone to wear.
If your engine is running at say 210 constantly then expect your transmission to run the same as they are joined at the radiator in a stock configuration (supercharging makes and generates more heat ).
Transmissions have filters: The filter collects particles of Clutches and Small metal shavings. The oil supply is drawn from the pan so the oil supply will slow when the filter is clogged.
If your bands are out of adjustment overheating can occur.
If your oil lines are clogged expect overheating
If your exhaust is too close to the transmission expect increased temperatures.
If your Engine Exhaust is too restrictive (clogged cat converters) the engine temp can increase.
If you have internal wear of parts overheating is not uncommon.
What are some things you can do to prevent overheating?
Do your scheduled maintenance and in some conditions do it more often. If you go off road or tow often, consider it not normal condition as the transmission works harder thus building more heat.
Do your filter changes: a clean filter will keep your fluid moving unrestricted
Have the mechanic check band adjustments: As the clutches wear they need adjusted and clutches that are not properly adjusted and lead to heat buildup.
Supercharging = More heat keep an eye on your gauges and temperatures.
More fluid capacity means better temp control: additional coolers, larger oil pans, in line thermostats, etc. can help you control heat.
Consider separating the cooling of the Transmission and Engine coolers: Often the temps vary from engine and transmission the engine often runs 20 or 30 degrees hotter and this decreases transmission life. A word of caution if you live in cold areas Canada, Alaska, etc. The Radiator provides preheat for the transmission and you need it when your oil is colder. I would not recommend rerouting the Oil Supply from the radiator in this circumstance.
Keep the Radiator surface clean: Allowing the surface area to be clogged with dirt and debris hampers good heat transfer. Keep those cooling fins washed and clean as much as possible.
Go to your dealer and ask: See what the latest warranty claims have been about or even talk to the mechanic he works on them all the time. These guys are a valuable source of information and can really give you ideas in what to look for.
Exhaust Maintenance is important: Often we ignore the exhaust accept when it is leaking. Cats and exhausts can become clogged and internal passageways loose and broken. Thermal wrapping exhaust can keep heat away from transmissions. Replace suspected exhaust components or consider larger diameter exhausts. Consider rerouting exhaust systems.
After market additives can help reduce heat: There are some synthetic base oils that reduce friction and that leads to reduced heat.
Consider higher volume Fans, thermostats, and aftermarket Fan systems: After market fans and thermostats can make the engine and transmission run cooler providing more surface area temperature control.

Waiting till the problem is present can lead to damage that may require you to have the transmission rebuilt. While the list is not everything it can provide a good basis to start and some ideas to assist you. All said and done overheating may be a sign of internal damage and not a lot you can do about it accept Inspection and possibly rebuilding of the Transmission. Happy Motoring!