Explorer Transmission Cooler

Hi guys, I'm putting a new rad in my Jeep and I figured while I'm at it I may as well add in a transmission cooler as well. I went to the junkyardgot a nice one from an explorer for $10 and I figured out how I'm going to mount it, but I need to know what line is the return line back to my transmission and what one is the feed coming from it.

I'm going to run the transmission cooler as well as have the fluid go through my rad. I want it to go through the cooler first, then through the rad, then back to the tranny. Reason being is that I'm in Edmonton, Canada. We have +30-35 (C) summers and -35 (C) winters. If I run just the cooler, I'll be fine in the summer but I don't want to run the risk of the ATF being too cool in the winter. So it'll go through the cooler then through the rad and that should help things stay in an acceptable range as well as take a lot of load off my rad.

So I need to know what line come from the tranny and one one goes back into it so I can hook up my cooler and rad in the proper order.

Thanks!
Mark

Oh and what should my rad cap be rated at? I bought a new one and the parts catalogue said it should be 13, but the old one I took off is only rated to 8... ('93, AW4, 4.0L HO)

Crawl under there and look, IIRC it was pretty obvious when I did that. Here's a link from when I did mine.

http://www.naxja.org/forum/showthread.php?t=91183&highlight=tranny+cooler

The line that goes into the top port of the rad comes from the tranny.

Thanks guys.

Another question I have... I bought the B&M transmission temp gauge and I'm wondering where I should install it in the system. The B&M install guide says on the return line leaving the cooler and going back into the tranny but that doesn't make sense to me because then it'll read the cool level and not the operating temperature of the tranny. Some guides online have said to put it in the line leaving the tranny so it reads the hot temperature but I'm not convinced that it's the best idea to go against what the install guide says...

Can anyone give me pointers either way?

If you put it in the return line after the cooler you will be reading the temp of the fluid your tranny is using. This is probably the most useful piece of info.

I installed it last night and I ended up putting it in the outgoing line from the tranny so I can see how hot the tranny itself is operating. I don't know if this is normal or not but it reads really low... it takes 10 minutes of driving for it to start getting a good reading and even still it only reads around 140 to 150C... I thought the reading should be much higher since I'm running 33's on stock gearing and there is a lot of slippage in the tranny.

Is the reading I'm getting normal or is my tranny running really cool or is the guage not reading right?

I got a full tranny flush done yesterday so I know the fluid is brand new in case that changes things at all...

Your readings are right.

In the summer it takes a good 20 min of driving for my 94 ZJ's tranny to get up to 150ish. In the spring and winter the tranny fluid rarely reads on the temp guage at all. However! When towing a trailer of 5k lbs if I don't turn overdrive off the temp guage will shoot into the red vey quickly so I know the guage is working. It just shows how much stress a heavy load can put on my transmission and why coolers and temp guages are so important for transmission life in "severe duty" use.

I have it on the outgoing side of the tranny as well.

Bender: WOW! In the summer here down south, my tranny fluid temp can be over 120 F after it's been parked all night. ( 'love the desert and don't want to move,...)

Your temps sound normal for no-load driving. Usually under 200 unless high-speed or high-load with high temps, I suspect some conduction from radiator temps also raises temps over time. Then any sort of load (trailer) or uphill, unlocked will quickly push temps up.

Location of sender? Have someone drill and weld a bung in your trans pan for actual fluid temp. An in-line installation must place the probe in the moving stream of fluid to be valid, not in a T off the line since that will be sensing static fluid that may not reflect the working temp. And of course the line and fittings themselves cause some conduction cooling. Simplest and cheap, more secure and accurate to go with a bung.