Here's the scoop:

2008 JK Sahara Automatic with 35,000 miles. Upgraded to the following a few months ago:
4.5 inch lift, long arm conversion
35 inch tires
5.13 gears

On vacation in Colorado and decided to drive up to the Bridal Veil waterfalls in Telluride (10,000+ feet). I was behind a Toyota and we averaged about 10 miles per hour the entire way up (kept in 'D' the entire way). Not a bad dirt road with the usual switch-backs and rocks. In retrospect the tranny was shifting a lot because we would catch up to the Toyota and then have to slow down.

About 50 yards from the top the 'Oil Overheated' (I think it said that) came on. I drove up to the parking spot and turned off the Jeep. The engine temp stayed great, never even moved to the 'Hot' side. We spent about 30 minutes there until it began to rain. We started the Jeep and it was fine, no messages. I drove back down the moutain in 2nd gear without any issues.

Any ideas why this happened? Should I worry about it? Should I have done something differently while driving to the top?

Any info is appreciated.

Bill

 

Your trans might have been too hot - 4 low might have been your best bet. My '08 auto is a real dog on a decent slope in 2 high. We did Black Bear a couple of weeks ago and coming down from the Power Station parking area I took it out of 4 low - down hill gravel road. Well I had to back up at one of the switch backs to let some traffic by and I was wondering if the trans was going to stall! I put it back in 4 low!

 

I did have it in 4 high so 4 low may have helped.

Thanks!

Bill

 

Yes 4lo would have helped.

4lo, in "D", O/D off, at the speed you quoted, would have let the transmission get to 3rd so the torque converter could lock. An unlocked torque converter is a huge heat generator.

 

Can someone explain to me the proper way to use 4WD with an auto trans? I have never wheeled with an auto and this last weekends adventure included a bit of a learning curve. Dos and don'ts anyone???

 

The first thing you should do is get a transmission temp gauge, and/or an additional transmission cooler.

I use 4hi on good dirt roads, and on snow covered paved roads, where, in both cases, it may be safe to drive fast enough to get the transmission into 3rd, where the torque converter can lock up.

I use 4lo on stuff that keeps my speed low. 4lo, "D", O/D off, and I can actually see the transmission temp come down as the torque converter locks up.
"D" is not always possible, but use it whenever you can.
Turning on the A/C will further drop the transmission temp, as it forces the fan to come on.
All this is why you should at least get a transmission temp gauge.

 

THANKS for the info guys!!

Bill

 

Thanks!!!!!

 

I wonder if there is a way to fool the TC into locking up. On an XJ it's no big feat to bypass the transmission controller so you can control the trans manually but it's a pretty primative system compared to this. It would be nice if you could tap into a wire that controls the lock up solenoid (if there is one) and control it manually. Just wishful thinking I guess!

 

I am headed to Moab this week to do some wheelin. Thanks for the info. I haven't had this happen but it is good to know how to fix it. I guess we all have something to learn.