spencersausser

OK, so I'm going with the "no such thing as a dumb question" angle here. I have a 96 XJ sport with the AW4 auto trans. I was thinking about installing a tranny cooler, however, when I was laying under the XJ the other day to mess with the NSS (cause my reverse lights aren't working), I noticed some hard lines coming out of the side of the tranny and I followed them up to see that they appeared to attach to the radiator? Is this the norm? I understand that engines have coolant passages to flow through. For some reason, I thought when there's a tranny cooler, the transmission fluid was what exited the tranny, went through the cooler and returned to the tranny. Are there coolant passages in the tranny, just as in the engine? Does what I've described (lines coming out and going to the radiator) sound right? I'm just not as knowledgeable about automatics. I usually have stick shift in my cars. Thank you to all who lend their thoughts.

Spencer

Caish

Yes that is correct, the tranny is water cooled. The oil flows from the tranny to radiator then back to the tranny.
If you want to add an auxillary(sp) cooler want to go from the tranny, to radiator, then to a cooler and back to the tranny.
You'll have to on hook the lines for a just a few seconds and have someone crack it over and see what line is the supply and return.

spencersausser

Thanks, Caish, but forgive me for not quite getting it. The lines out of the tranny go to the regular radiator. Does that seem normal? Is regular engine coolant also flowing through coolant passages in the tranny as well?

Thanks.

Caish

Now the only thing that flows through the small lines is transmission fluid.
This cutaway shows what a cooler looks like inside the radiator.
See #5

Its not a jeep radiator but the same parts apply and are there. Best I could find in a minutes time.

djb383

All automatic trannys pump hot tranny fluid to the cool side of the radiator, then the cooled tranny fluid flows back to the tranny. No engine coolant goes to the tranny, just tranny fluid to the rad (and back).