42RE question pertaining to radiator change

[04 LJ]

I am 95% done installing my entirely new cooling system in to the LJ. I went ahead and changed the trans fluid lines that hook to the bottom of the rad and that’s where my question arises. Is there a reservoir inside the bottom of the radiator that will need replenishing or does the fluid just circulate through in an “in and out” fashion? If there is a reservoir, I’m assuming it will refill itself from the main fluid storage in the pan and then I will just need to top off the pan with new fluid to make up the difference? I lost very little with the hose change, maybe a few drops.

If I have to add, is any particular type of fluid recommended over another? I don’t know what I have in there now but I’ve only put about 150 miles on it since I bought it last year. Fluid appears nice and red in color but does have a slight odor. When I bought it, they put a new rear main seal in but I don’t know if they messed with the trans or not during that operation. Also have no clue if changed it as part of their “pre lot service” they do before putting out for sale.

Thanks all!

 

[Thunderhead]

If there is a reservoir, I’m assuming it will refill itself from the main fluid storage in the pan and then I will just need to top off the pan with new fluid to make up the difference? I lost very little with the hose change, maybe a few drops.

If I have to add, is any particular type of fluid recommended over another? I don’t know what I have in there now but I’ve only put about 150 miles on it since I bought it last year. Fluid appears nice and red in color but does have a slight odor. When I bought it, they put a new rear main seal in but I don’t know if they messed with the trans or not during that operation. Also have no clue if changed it as part of their “pre lot service” they do before putting out for sale.

Thanks all!

Definitely run it and check it, hot, park or neutral,
it will “refill” the bottom of the radiator as it passes through.
Only use ATF+4 in your 04

 

[04 LJ]

Thanks! Any particular brand? Do keep in mind I don’t know what’s in there currently.

 

[Jerry Bransford]

Thanks! Any particular brand? Do keep in mind I don’t know what’s in there currently.

Literally any that is labeled "ATF+4" will be fine. If it doesn't say ATF+4 in big letters on the front label it's the wrong stuff. Make sure the engine is running while you check the ATF level.

 

[04 LJ]

Thanks Jerry. May not know it all but know to check the atf while running on a level surface