About a month ago I was dealing with my XJ shutting down after 40 minutes of driving, and I knew that at 150k it was still rocking the stock cooling system, so I replaced the rad,thermostat, water pump, and coolant lines. The Jeep ran tip top, but I noticed that the "quick disconnect" on the supply line to the rad was leaking.

Knowing that I was buying a truck soon and it would be a trail rig from now on, I went and picked up the biggest aux cooler that I could at O'reilly and installed it. No more leak, but the trans tunnel is obnoxiously hot. I picked up an IR thermometer and am getting the following temps: Floor(no carpet) 150F, aux cooler 135F, supply line 180F, return line 165F, trans pan 185, top of trans 195.

Now I know the IR thermometer could be a decent amount off, but with a 9.5"x11" cooler installed in front of the clutch fan, I feel I should be seeing a much lower number, even in 85F ambient.

I did a drain and fill at about 140k and the fluid looked pretty dark, but didn't smell burnt. It is still redish, starting to get a little darker, but again, no burnt smell.

Could this be the internal clutch packs burning up? Any recommendations to get me through a few fall/winter wheeling trips before I look for a replacement trans?

99 Sport 4.0 auto, 4.5" RCLA, 4.56 gears, lokka front and rear(D30,C8.25).

Thanks!

 

is the cooler in line with the rad? I had a big trans cooler on mine that bypassed the rad, it was cooling too well. even in the summer the fluid temps were barely achieving 100*. I took the cooler off and ran it back through the rad.

if yours is in line it seems about right. it should be pretty consistent 180-190. I think your trans is fine.

 

Nope. Bypassed the rad entirely because of the leaking quick connect. It shifts normal, and i don't feel like its slipping at all, just seems like it's getting a lot hotter in the rig than it used to.

 

9.5x11 isn't really very big, but it should be enough. How big are the tubes? Maybe you aren't circulating enough fluid.

As for the fluid color, check my sig, #3.

 

That is what mine runs at being bi-passed with just the cooler. The AW4 runs hot in traffic and up hills in 90 degree heat I could see temps on my gauges at 190-200 on the hot side, and about 30-40 degrees cooler on the cold side. On the highway with the torque converter locked the fluid is going through the cooler more and subsequently cools down the trans to about 160-170 in 90 degree heat on the hot side.

here is a pic of the gauges. White hot side, black cold side this was sitting idle after driving to work.

 

Anyone else have any ideas?