Trans coolers

[Bobmontana]

While towing our 3000lb travel trailer with our 2011 Yukon xl 1500 5.3 litre I found that it does ok for the most part but the transmission did get up to 220 degrees going over Macdonald pass in Montana. We were down to 45mph and 3000 rpm just as we crested over and the trans gauge touched 220. Has anyone replaced the stock cooler with a larger one that is a OEM ? I don't like the idea of scabbing in a cooler attatched too the radiator and just rubber hose clamped to the lines. Than you for your time.

[Roger10378]

I like to see trans temperature reach 220 occasionally. Water condenses in the trans oil and needs to be boiled out occasionally.

[Roger10378]

I like to see trans temperature reach 220 occasionally. Water condenses in the trans oil and needs to be boiled out occasionally.

[MitchF150]

As long as it cools down again when you are not working it hard, then your current cooler is doing it's job.

Your trans probably has an internal thermostat on it anyway.. So, it'll only cool down so much anyway.. Probably around *190-195 range.

If you do decide to get more cooling for the trans, don't add a second cooler... Get a bigger cooler than OEM and leave it all plumbed the same way.

Good luck! Mitch

[Lwiddis]

220F is the upper limit but not excessive IMO when going up a grade with a trailer.

[Turtle_n_Peeps]

220 for modern ATF synthetics is not hot at all. Warm, but not hot.

The warning chime for my truck comes on around 265 or 270?

You can put another cooler on as you have said but there really is no reason too. The problem also it if you do cool off the tranny then those BTU's will go into the engine coolant stack and that can cause problems too.

Not saying to not put another ATF cooler in the stack, I'm just telling you some of the drawbacks because very few on this site seems to want to talk about those.