Transmission cooler

[Crichey6559]

I’m currently looking at buying either a 1999 Yukon slt 4wd or 1999 Yukon Denali. I’ve read up on most of the common issues but one thing I haven’t been able to find is how to tell (without physically being at the vehicle) if it would have come equipped with a trans cooler. I’ve seen a lot of horror stories about these failing and pumping coolant into the trans killing it. Wanted to know in advance if it had one before going to look at these 2 so I could plan to disable the factory one and go aftermarket if it did. Thanks

Also is there a normal life for the trans? Typical failure mileage? Like 150-200k or mostly random

 

[east302]

The auxiliary cooler is a small coil on the front of the a/c condenser. You can see it through the grille.

Here's a link with photo...

http://www.gmt400.com/threads/how-to-factory-auxiliary-trans-cooler-upgrade.18104/

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The transmission lines connect to the radiator on the passenger side. The oil cooler lines are on the driver side. Here's one of the transmission lines, the other is at the bottom by the radiator hose.

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[Crichey6559]

Thank you very much. Want this vehicle to last a long time and ensure there are no avoidable issues

 

[Dan_Frisbie]

All automatic transmissions have a cooler. Nearly all have it in the radiator. Some have an auxiliary cooler outside the radiator.
If you're looking at a GMT 400 with an auto, it has a cooler in the radiator.
I've never heard of one failing in the radiator and filling the transmission with coolant, though.

 

[El Tigre]

While my C/K is still plumbed in the factory configuration,my late model Impala SS is not. Radiator cooler failures are not common,but they have happened. Yes,the transmission is quickly destroyed by coolant. Before starting down this road it's important to have installed a trans temp gauge. Additional cooling may be called for,and high fluid temps kills far more transmissions than coolant does.

 

[Ken K]

I have always found this an interesting concept. It seems strange to think the an automatic transmission is cooled with coolant running between 195 - 220 degrees F. Running thru the radiator first, cools it down from a higher temperature, then if an external cooler is installed, it would drop the temperature even more. A Tech2 and some late model trans will show fluid temp and i have never went there to take note. Your post indicates your location as Madison... if this is Wisconsin, It gets real cold as in Omaha, Jan 1st, our temp is -17 for the low and -1 for the high. If you run an external cooler only, how will that effect the transmission's performance? Will it slow shifting? Will it cause slow release, allowing two locking devices to remain engaged at the same time, due to slow release? On some vehicles, over-drive, torque converter lock-up is denied, until the engine reaches operating temp. Whether emissions, internal loads or mechanical strain on valves, solenoids, accumulator are the issue...how will they function when the fluid is cooled to 50 - 180 degrees? I have been inside more trans to repair or overhaul than I can remember, but have never wrapped my head around this question. I think I once saw a temperature sensing valve that could by-pass using a bi-metal internal element to direct the coolant flow of the red juice, but don't recall.
I am sure there are many who run their coolers this way and have first hand knowledge of results...but i am still curious about winter time ops for those who live where we deal with ice, snow and -30 boots! What say YOU guys & gals who run this way?
Call it, trans fluid cooling commando style!!

 

[Supercharged111]

These trucks do deny TCC lockup below a certain temperature. Some of the coolers out there have different size passages that don't allow as much fluid through when cold to assist in warming up the fluid. That said, when it gets good and cold, my 1500 has trouble getting past 100 degrees with its factory auxiliary cooler in series with the radiator cooler. For the dually, if I ever get the motivation, I'd like to run a much larger cooler with a thermostat so the fluid runs a steady 150 or 180.

 

[El Tigre]

http://www.improvedracing.com/oil-t...transmission-fluid-thermostat-165f-p-423.html This is the thermostat I installed between my two coolers. They also offer a 145,and 185 degree version. These work very well,as do all their products...