Do tranny coolers solve the problem

[alphascott]

Hello to you h3 alpha owners with over heating problems due to transmission running to hot and installed an additional tranny cooler

My question is, DID IT SOLVE THE POBLEM ?????:whaa:

 

[amrg]

Im running a standalone trans cooler, my trans temps dropped from ~215 f to 175 and thats with 35s @ 115+ weather. To me thats a huge improvement plus I got piece of mind not having to worry about cross contamination (stock radiator tends to fail and the atf gets mixed with the coolant leading to burnt transmission)

 

[alphascott]

thanks man

yes those are impressive numbers especially with a 115 amb
I couldn't make up my mind weather to do stand alone or add it into the circuit with the radiator, I to have heard the horror stories about the stock radiator and contamination
I am getting ready to replce the radiator , yes it did crack at around 78000 miles , talk about planned obsolescence, I will at that time separate the two

Im experimenting with a fan on the trany cooler for the purpose of off road while towing the ATVs
the cooler does great at highway speed but going for 65mph air to 5mph air at 12000 feet in the Colrado summer sun seams to be where trouble starts
thanks for your help with this , I was getting ready to get rid of my 35s
all the best
Scott

 

[amrg]

thanks man

yes those are impressive numbers especially with a 115 amb
I couldn't make up my mind weather to do stand alone or add it into the circuit with the radiator, I to have heard the horror stories about the stock radiator and contamination
I am getting ready to replce the radiator , yes it did crack at around 78000 miles , talk about planned obsolescence, I will at that time separate the two

Im experimenting with a fan on the trany cooler for the purpose of off road while towing the ATVs
the cooler does great at highway speed but going for 65mph air to 5mph air at 12000 feet in the Colrado summer sun seams to be where trouble starts
thanks for your help with this , I was getting ready to get rid of my 35s
all the best
Scott

I just thought Id add that I added the Tru Cool 30K trans cooler (rated 34k BTU) listed here

http://www.transmissioncoolers.us/category/trucool-MAX-cooler.html

I would've went even bigger but I had electric fans and I was worried about size constraints. Honestly I think a 40K would've fit!

They also have a bypass for colder weather applications

 

[silvrzuki77]

This is my next mod

 

[f5moab]

Anytime you add another cooler into the cooling system, it will drop the temps. However, the trans temps should not increase that much unless you are doing a lot of mountainous driving, or pulling a trailer. I have an I5, and my trans temps never raised that high when off-roading or normal flat level driving. However, in the mountains the temps did go up, but nothing to really get excited about. However, when I started to pull a trailer, I decided to jump into an external cooler. It is an external stacked plate BM, 44K cooler and it does the job.
It is in series wit the standard radiator cooler.
There is NO warranty data that shows the H3's internal radiator cooler fails in any greater numbers than any other internal radiator cooler out there. Internet data is always suspect since most will report a problem on various sites, thus increasing the the belief there is a problem. (Radiator does have a top tank problem.) Then you have a few report it on a particular site, but run those numbers not against those on the site, but run the number against ALL H3s produced and suddenly that number of radiator failures drops to norms for all other vehicles.
However, nothing wrong in bypassing, just make sure the trans temp can rise to at least 150 degrees. It is more efficient at that temp.

When the H3 Alpha was replaced, it was pretty unanimous in engineering that the radiator specs appeared to be too small for the engine. I left GM before any data was fed back into the system, and I never had anyone look it up out of curiosity (since I don't have an Alpha...didn't care).

 

[silvrzuki77]

Good info F5, I havent had any raise in temps till I started pulling a trailer offroad. Even then I was in Death Valley 110 outside temp, in low range towing my teardrop on 35's. It barely moved past its normal temp. New trailer to pull offroad.

 

[Sennin]

[FONT=&amp]My problem comes in with towing my new Offroad caravan, pulling the scale at 1.8 ton (3,968lbs) when loaded and all water and fuel tanks filled.

and then doing a 200km (124mile) track at 20kph in second gear on a road looking like this:

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[silvrzuki77]

Thats a sweet caravan!

 

[Sennin]

Recieved xmas early today. Recieved my spacers for the caravan wheels to track in the hummers path. And also recieved my tru cool atf cooler [emoji48]

 

[amrg]

Is that the 40K? Lemme know how you have it installed, looking to upgrade my cooler since Im moving to 37" tires soon!

 

[Sennin]

Is that the 40K? Lemme know how you have it installed, looking to upgrade my cooler since Im moving to 37" tires soon!

Jip its the mother of all coolers. My first thought was the pipe it gets supplied with is going to be 2 short i want to mount the cooler with its in and out at the top

 

[amrg]

The hose is barely enough for the cooler to be mounted on the front, 30 cms extra hose would make installation extremely easy!

 

[Best4x4]

I had a stand alone on my wife's H3 but it took it a while to reach the preset warmup temp of 80-90F and it caused OD not to engage until like 5 miles down the road. I removed it and reconnected it to my Silla Radiator and it shifts fine again when first cold. If I was to do it again I'd run it inline of the OEM setup to allow it to warm up the same as OEM, but provide extra cooling. The OEM cooler inside the radiator doesn't fail the O-Rings between the radiator and cooler are the issue. Silla's design is much beefier in that department! I run tranny temps from 186-229F on my 07 I5 (with 229F being the most extreme summer heat). On my Alpha I get 195-213F transmission temps.

So I suggest either the 180 thermal bypass with the stand alone cooler or run it inline with your OEM setup. Pure 100% stand alone will cause the transmission not to warm up properly during the winter months.

 

[06 H3]

Im standalone but use a bypass valve till 160 degrees. Mine shifts fine right off the bat.

 

[Best4x4]

Mine shifted fine, but since the tranny took so long to warm up it wouldn't go into OD. Once warmed up boom, but to me 5 miles of not being able to run OD was stupid. A bypass is a must on a stand alone setup!

 

[amrg]

With the 30k standalone trans cooler Im running, I only hit 185f - 190f at extreme conditions! (Wheeling with 35s, aired down to 10 psi, repetitive full throttle and holding first/second gear for extended periods, all that in 115-125 ambinet temps). Before the external cooler, I was running up to 220f in normal driving conditions which is what pushed me to get the external one. Cold weather is no issue in this region. My only regret is that I didnt instal a 40K cooler from the start!

 

[Panzer07]

Stupid question here...would installing this transmission cooler help to lower my engine gauge temperature. I just installed a new thermostat, and don't like the fact that I'm running twice as hot as I did before...and it is cool weather California right now 40-60 I'm a little skeptical on running this hot on the California summer 90-110 temperatures


Torres

 

[Best4x4]

It's way more humid here in TX Panzer and my 3.7L H3 with the 190F thermostat did just fine. The 190F is 10 degree's warmer so your temp range technically is only changing 10 degree's. My 07 H3 before the new thermostat was 186-196F and now it's more like 196-206F with the max being 216F sitting in horrific traffic. The gauge is extremely sensitive and 198/200 is normally dead center, while between the 1/2 to 3/4 mark is anywhere from 200 to 216F.

 

[Sennin]

I did puchase the kit with the bypass included, but I wont install the bypass from the get go, will first install the cooler in series with the stock cooler, and if I experience the same OD issues, i will then either have a look at the shifting tables via the HP tuner. Or as a last resort install the bypass. I have a general checklist i do each time i start up, as the H3 is driven rarely. So i usually check fluids etc. Then start engine. And then check ATF etc and by the time I shift out of park the bullydog always indicates opperational temperatures.

AMRG you dont have photos of how you routed your lines to the cooler? I dont want any eccessive bends nor interference and rubbing

 

[amrg]

http://www.hummer4x4offroad.com/forum/showthread.php?p=138643

Thats the only pic I gave of the cooler installed. The top line is routed around the chrome grille mounting bolt (it also was a very tight fit so 30cms of extra hose wouldve been perfect for that mount)

 

[Best4x4]

With the cooler inline of the OEM cooler you should be fine.

 

[Jeremy]

I don't think it's just an Alpha problem. My 07, the 3.7L, tranny is being gutted and rebuilt because it burnt up on the inside.

 

[Sennin]

I don't think it's just an Alpha problem. My 07, the 3.7L, tranny is being gutted and rebuilt because it burnt up on the inside.

Jip, experienced the same problem with my 3.7 before i upgraded to the V8. On the V8 it was less of an issue towing my trailer. But upgradimg to the caravan im doing preventative upgrades

 

[Best4x4]

From what I can tell by owning a 3.7L & 5.3L is that due to different RPM's at speed the transmission engages/disengages the torque converter differently. I can see it via my ScanGauge II and monitoring the temps. In a headwind the 3.7L transmission temps will rise due to trying to maintain speed vs the 5.3L which doesn't seem to care as much unless you're pushing much higher speeds say 80MPH and up. It's also about torque period and the 3.7 & 5.3 are different beast.