Hot Oil Light
#11
JK Jedi Master
Yes, the engine's fan will pull air through the additional cooler.
#12
JK Enthusiast
Join Date: Sep 2016
Location: California
Posts: 256
Likes: 0
Received 0 Likes
on
0 Posts
Oh nice that's good to hear. Thanks for the info! I'll probably just go with the Mopar. You noticed a decent amount of temperature change?
#13
JK Junkie
Another point worth discussing - the use of 4HI vs 4LO. The auto trans will be more prone to overheat when operating off road in 4HI. If you are going relatively slow, you should be in 4LO.
#14
JK Enthusiast
Thread Starter
I was in 2 high when mine came on. Just a dirt/gravel road, not a lot of tire slipping but a pretty decent grade.
#15
JK Junkie
I bet if you switched to LO the light would have gone out. The trans needs to do less work when the transfer case is in LO. The general rule I follow: on snow covered paved roads i use 4HI. When off road, I use 2HI for fire roads, then shift to 4LO if i feel the need to be in 4wd. I rarely use 4HI off road.
#16
JK Enthusiast
Join Date: Sep 2016
Location: California
Posts: 256
Likes: 0
Received 0 Likes
on
0 Posts
I bet if you switched to LO the light would have gone out. The trans needs to do less work when the transfer case is in LO. The general rule I follow: on snow covered paved roads i use 4HI. When off road, I use 2HI for fire roads, then shift to 4LO if i feel the need to be in 4wd. I rarely use 4HI off road.
Although my jeep has never had the light come on.
#17
JK Junkie
The addition of a trans cooler was the permanent fix. Does the Toyota have a cooler? Jeep made them standard starting with the 2012 model year.
#18
JK Enthusiast
Join Date: Sep 2016
Location: California
Posts: 256
Likes: 0
Received 0 Likes
on
0 Posts
#19
JK Jedi Master
Now, the water temp is allowed to climb pretty high before the electric fan comes on; too high for transmission fluid. So, with the pre-2012 JKs, they moved the fluid out of the radiator and put an external cooler, which was too small, behind the bumper. Not enough air could get to it.
They fixed that in 2012 with a larger external cooler, mounted in the direct path of air coming through the grill. I haven't heard of any 2012+ JK automatic transmissions overheating.
Like mentioned above, 4lo will reduce the amount of heat generated in the torque converter for a couple of reasons.
First, there will be less shearing of the fluid in the turbine.
Second, the transmission may get into 3rd gear, where the torque converter can be locked.