Is this transmission cooling setup normal/acceptable

[El Tigre]

All this hand wringing about transfluid warming up when heat is what destroys many,if not most transmissions. Noting will warm up the trans faster than a trans fluid thermostat,and without the risk of coolant contamination of trans fluid... Which is always a possibility when using the cooler built into the vehicle's radiator of which I'm not a fan.

 

[thegawd]

When I had my trans rebuilt in my burb they did an analysis of the trans fluid and found coolant. For sure the initial cause of the original transmissions failure and then of the junk yard trans that gernaded 20 000 kms later. It was not visually seen on the dipstick and I never had milky coolant. I used a mom n pop race shop that's been rebuilding trannys for over 50 years and they always analyze the transmission fluid. A pressure test proved the leak. Since I had a budget they recommended bypassing the rad and using the existing original external tranny cooler that was never connected. It had the HD towing package rpo and I knew what it contained but was very suprised to learn that like the 7 way plug the tranny cooler needs to be completely installed either by a dealer, a trailer place or yourself.

This was like 5 years ago and all is still perfect. The stage 3 heavy Duty tranny performs just like the day I got it back from being rebuilt, the truck was also tuned as a part of the deal. So I can definitely agree that bypassing the oem setup does not cause any harm whatsoever and is recommended by the best in the business.

Al

 

[BhutJolokia]

All this hand wringing about transfluid warming up when heat is what destroys many,if not most transmissions. Noting will warm up the trans faster than a trans fluid thermostat,and without the risk of coolant contamination of trans fluid... Which is always a possibility when using the cooler built into the vehicle's radiator of which I'm not a fan.

Last two posters you make excellent and legitimate points about heat and coolant contamination. However, that still leaves me where I am now, with temperatures over 200 on 90+ degree days on steep grades at highway speed.

I checked the cooler on there now and it is a Hayden. There isn’t much room for anything bigger or a second cooler without blocking too much of the condenser. Should I just live with high transmission temperatures for short bursts in summer in the mountains or is there a better solution to the inadequate cooling? A fluid thermostat is a good solution for sub zero days in the mountains but does nothing on the hot end.

 

[df2x4]

When I 4L80E swapped my red truck I kept the radiator's internal transmission cooler functional and installed a Tru-Cool M7B AUX cooler in addition. My line of thinking was that if the transmission fluid temperature ever spiked rapidly for some reason then having the radiator cooler would probably help bring it down faster than just the AUX cooler. I understand why some people bypass the radiator cooler and if I ever have issues with one I may consider doing the same, but I haven't so I didn't. (Knock on wood)

I checked the cooler on there now and it is a Hayden. There isn’t much room for anything bigger or a second cooler without blocking too much of the condenser. Should I just live with high transmission temperatures for short bursts in summer in the mountains or is there a better solution to the inadequate cooling? A fluid thermostat is a good solution for sub zero days in the mountains but does nothing on the hot end.

I would consider installing a different AUX cooler with a fluid thermostat if you want to continue to bypass the radiator cooler. The Tru-Cool M7B I mentioned can be fitted using the factory AUX cooler brackets if you trim them a little. Instructions to do so can be found here:

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

A few other members here have installed much larger coolers as well. @Curt is in the process of installing a Tru-Cool H7B which is massive.

https://www.gmt400.com/threads/time-to-get-serious-with-4l60e-4l65e-cooling.50138/

 

[Curt]

When I 4L80E swapped my red truck I kept the radiator's internal transmission cooler functional and installed a Tru-Cool M7B AUX cooler in addition. My line of thinking was that if the transmission fluid temperature ever spiked rapidly for some reason then having the radiator cooler would probably help bring it down faster than just the AUX cooler. I understand why some people bypass the radiator cooler and if I ever have issues with one I may consider doing the same, but I haven't so I didn't. (Knock on wood)



I would consider installing a different AUX cooler with a fluid thermostat if you want to continue to bypass the radiator cooler. The Tru-Cool M7B I mentioned can be fitted using the factory AUX cooler brackets if you trim them a little. Instructions to do so can be found here:

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

A few other members here have installed much larger coolers as well. @Curt is in the process of installing a Tru-Cool 40K which is massive.

https://www.gmt400.com/threads/time-to-get-serious-with-4l60e-4l65e-cooling.50138/

Thanks for the mention df2x4. Mentioned in my thread a little while ago, I found out the radiator was bypassed and changed my direction since then. I opted to upgrade to a 454SS radiator paired with a Tru-Cool H7B cooler. No more installing a massive 40K, I don’t see myself ever needing a cooler that massive after finding out about the bypass someone did.


Sent from my iPhone using Tapatalk

 

[df2x4]

Thanks for the mention df2x4. Mentioned in my thread a little while ago, I found out the radiator was bypassed and changed my direction since then. I opted to upgrade to a 454SS radiator paired with a Tru-Cool H7B cooler. No more installing a massive 40K, I don’t see myself ever needing a cooler that massive after finding out about the bypass someone did.


Sent from my iPhone using Tapatalk

You caught me before I edited my post. I actually remembered what you were doing right after I clicked the button. Only changed one word of my post though, the H7B is still pretty massive IMO.

 

[El Tigre]

Last two posters you make excellent and legitimate points about heat and coolant contamination. However, that still leaves me where I am now, with temperatures over 200 on 90+ degree days on steep grades at highway speed.

I checked the cooler on there now and it is a Hayden. There isn’t much room for anything bigger or a second cooler without blocking too much of the condenser. Should I just live with high transmission temperatures for short bursts in summer in the mountains or is there a better solution to the inadequate cooling? A fluid thermostat is a good solution for sub zero days in the mountains but does nothing on the hot end.

On another vehicle with deeper gears,and a higher stall converter I do use two trans coolers with a 165 degree thermostat between them. Resulting in trans temps between 160-180 degrees most all the time. Very little trans fluid flow in the second cooler until it gets hot. Can always turn on electric fans manually if situation demands.

 

[Pinger]

Is it reasonable to assume any oil thermostat's flow rate (open or closed) can be judged by it's connection sizes?
ATF coolers are rare in the UK but engine ones are easier sourced. An engine one with 3/8'' connections - suitable for a 4L80E with 3/8'' OD hard lines?

 

[Pinger]

Was out with mine today, drove about 15-20 miles at 50-70mph and when I got back and put the back of my fingers on the cooler - nothing close to even warm. Ambient here today around 15C (59F).

 

[alpinecrick]

These are the best I've ever seen/used. Available in 145,165,185,and 215 degree versions.http://www.improvedracing.com/oil-t...sion-differential-fluid-thermostat-p-423.htmlhttp://www.improvedracing.com/oil-t...sion-differential-fluid-thermostat-p-423.html

That's still a mechanical bypass. The true stacked plate coolers have a passive bypass in the first inlet passage that directs cold (more viscous) fluid directly to the outlet, bypassing the rest of the cooler until the fluid warms up. Like any thermostat the mechanical bypass will eventually fail. Of course, they may last a LONG time before they ever fail........