Hey,
Last weekend i was doing a medium rough trail (The Pinnacle Trail at the Cove Campground in Gore, VA if anyone is curious). About halfway up, I got a Hot Oil waring light on the dash. Also, the fan was running hard. I let the Jeep sit for a bit. Eventually the fan quit and the warning light went a away. It did this one other time on the way up.

The weather was cool, about 56 degrees. I have done this trail before with no issues and it was a really hot day. The only thing I have changed on the Jeep are the tires. Changed to slightly larger BF Goodrich All-Terrain's.

Any ideas?

Thanks!

 

What year is your Jeep?

 

You should include more information about the circumstances.

I assume an automatic because of the hot oil warning.

What gear was the selector in?

Rubicon or not? (T-case 2.73:1 or 4:1)

Were you in 4lo or 4hi?

Crawling or mad dash up the hill?

End result will most likely be: Install a tranny cooler.

 

Sorry for the lack of info:
2008 Wrangler Unlimited X with Towing package (I believe that includes the tranny cooler
Automatic
4hi
Crawling up.

Thanks for the help!

 

There is no extra cooler with the towing package. Only the (inadequate) stock cooler.

What gear was the tranny lever in?

 

I would call your dealer and see if that will store a fault code they can pull. I have an auto run 37 on the stock 4:10s, live in Arizona and often run in 4low in 100+ degrees and have never seen that. If it is transmission oil which I am guessing it would be you may have a faulty temp sensor.

 

I will assume you had the selector in 1 or 2, or if you had it in D, you were not going fast enough for it to shift to 3rd.

Next time on the same hill, try this:

Get into 4lo, and put the selector in D, turn off the O/D. Being in 4lo will keep your speed down, but allow the tranny to shift into 3rd, and the torque converter will lock up. This will reduce the tranny temps. Turning on the A/C should force the fan to come on, instead of waiting for high temps to do it.

The way you had it set up, the torque converter was always slipping, generating lots of heat.

Adding a cooler will be very beneficial to your transmission.

 

Mine did the same thing on a trail I had run twice before with no problems. But I know why! First two times I was crawling up on 4L and 1st gear. This time I put it in 4h, and went all the way up in 2nd. It turned on at the end of the climb, so no problem there.

 

There is no engine oil temp sensor in the JK so if it says "Hot Oil" it means that the auto tranny fluid is getting too hot. Unfortunately the "Idiot light" only comes on when the tranny oil hits like 215 or 220 degrees F which is WAAAAAAAAAAAAAY too hot for tranny fluid. If your tranny hits that temp too often the fluid will break down and it will start slipping and eventually either boil over the fluid (which starts a fire) or just ruin the tranny. This is an extreme but both senerios have happened before. That is why jeep issued the recall last year to re-program the computer to say hot oil. I would absolutely add a tranny cooler, therre is an excellent write up in the writeup section for a B&M cooler it only takes 2-3 hours and costs like $60 for everything.

If you want to go fancy you can add the same cooler but with a fan. I did this last weekend and posted a write-up. The fan is probably overkill and it is something you can add later if you want. but I would definately add the tranny cooler before your next rip out. Good Luck!!

 

I believe that the 2007s do not have the Hot Oil warning. Someone correct me if I am wrong.

The 2008s got recalled to add the feature.

GeoFishnJK, I'm thinking you may need a transmission temp gauge, an auxiliary cooler, and maybe some fresh ATF.