[Mighty Thor]

This is for my 99 with automatic trans. My radiator gave out and the local parts store had one in stock. And it was really badly bent. So they ordered another one. It arrived and they said it looked straight so I brought it home. I also bought an Aux tranny cooler cause I have had need to pull a utility trailer on occasion. Anyhow, when I pulled the Rad out of the box it has threaded fittings for the cooler inside the Rad, but my XJ has one quick disconnect and one compression fitting. Neither will hook up to this RAD. I am thinking of just skipping the cooler in the Rad and just running the aux cooler in front of the Air conditioning condenser. Anyone see a problem with this set up?

[mp15dc]

The only problem would be in the winter,the tranny would not get up to operating temp. cold temps are just as bad as too hot temps.

[Mighty Thor]

Originally Posted by mp15dc

The only problem would be in the winter,the tranny would not get up to operating temp. cold temps are just as bad as too hot temps.

How so? My transmission works fine when you first start the car in the winter. It is not hot then, Often it will get me to work before the thermostat opens and puts hot water into the radiator. During all that time it is at the same temp as it would be with an Aux cooler. Not trying to be argumentative I just want to make sure I understand a specific concern, that way I might be able to figure out a work around

[mp15dc]

When you have a tranny cooler in the rad, the coolant will warm up from the heat of the tranny oil,the oil goes back not as warm, but the oil temp will rise. with just the aux tranny cooler, there is no warm up, the tranny oil goes back cold in the winter. with both coolers the temp will still rise but it will be slower and the tranny operating temp will be lower. cold temps are hard on the internal seals,it makes them hard.

I use two coolers on my truck and the shifts are harsher in the dead of winter, iam going to install a thermostat for the tranny to regulate the temp, its only a major problem when drive long hiway time and very cold temp. like colder than -30c/-22f . i dont drive when it gets below -45c.

I have just a aux cooler in my car and i have no problems when temp around freezing or above.

I hope some of this helps.

[mp15dc]

Just like to add, i reread your post, i have seen and had trannys fail when cold
they mostly fail in reverse,because of very cold temps plus the high oil pressure to engage reverse gear. the cold hard seals cant take the full oil presure.

Your tranny will still work when cold.
if you use just the aux, you could block the air flow to the cooler in the winter.

also it is possible to have condensation build up in the tranny if it operates too cold or does not come up to temp to boil off the water. It all depends on how you drive the vehicle.

[1990JEEPXJ]

some of the better coolers have some sort of built in thermostats. i would think this would help them warm up a little faster