Transmission cooler installed and hot oil light still came on off roading.

JeepNfish20

JeepNfish20

New member
I have a 2011 3.8 door JK automatic and curious if I should use 4hi or 4 lo offroading and to keep it in drive, 1 or 2? I have a b&m transmission cooler installed and a few weeks ago off roading my hot oil light still came on. I had it in drive 4 high and drive doing some good sized rocks. I recently read to always use 4 lo. Can you guys give me some input on this. Thanks !
 
J

JKDream

Guest
JeepNfish20 said:
I have a 2011 3.8 door JK automatic and curious if I should use 4hi or 4 lo offroading and to keep it in drive, 1 or 2? I have a b&m transmission cooler installed and a few weeks ago off roading my hot oil light still came on. I had it in drive 4 high and drive doing some good sized rocks. I recently read to always use 4 lo. Can you guys give me some input on this. Thanks !
Click to expand...

What gears are you running?
I always overheated until I regeared.

I only use 4lo for very steep climbs or if I'm in the rocks, mud etc. Otherwise I'm in 2wd.
 
J

JKDream

Guest
JeepNfish20 said:
I'm with 35s and stock gears at the moment
Click to expand...

That's most likely what is causing the overheating.
I would also change the fluid, if it's gotten too hot the fluids most likely burnt.
I would be using 4LO pretty often to increase your effective gear ratio until you regear.
 
BaddestCross

BaddestCross

Active Member
Yup. 4lo on the rocks. I usually leave it in 2nd or D when going in between obstacles depending on the terrain and drop into 1st for slow crawls over the rocks.
 
jeeeep

jeeeep

Hooked
JeepNfish20 said:
I have a 2011 3.8 door JK automatic and curious if I should use 4hi or 4 lo offroading and to keep it in drive, 1 or 2? I have a b&m transmission cooler installed and a few weeks ago off roading my hot oil light still came on. I had it in drive 4 high and drive doing some good sized rocks. I recently read to always use 4 lo. Can you guys give me some input on this. Thanks !
Click to expand...

you really shouldn't be getting the hot oil light since you installed a cooler - you double checked the flow direction so that the fluid runs through the cooler properly?

you checked the ATF level and filled with MOPAR ATF to make up for the cooler capacity?

where is the cooler mounted?
 
JeepNfish20

JeepNfish20

New member
jeeeep said:
you really shouldn't be getting the hot oil light since you installed a cooler - you double checked the flow direction so that the fluid runs through the cooler properly?

you checked the ATF level and filled with MOPAR ATF to make up for the cooler capacity?

where is the cooler mounted?
Click to expand...
Right up front behind the grill. And the fluid should all be good.
 
JeepNfish20

JeepNfish20

New member
BaddestCross said:
Yup. 4lo on the rocks. I usually leave it in 2nd or D when going in between obstacles depending on the terrain and drop into 1st for slow crawls over the rocks.
Click to expand...
What about going up hill climbs and steep obstacles? 4lo and should i use 1 2 or d for that?
Thanks
 
JeepNfish20

JeepNfish20

New member
JKDream said:
That's most likely what is causing the overheating.
I would also change the fluid, if it's gotten too hot the fluids most likely burnt.
I would be using 4LO pretty often to increase your effective gear ratio until you regear.
Click to expand...
Now when you say often do you mean keep it in 4 lo the whole time on the trails ?
Code:
 
J

JKDream

Guest
JeepNfish20 said:
Now when you say often do you mean keep it in 4 lo the whole time on the trails ?
Code:
Click to expand...

If it's a trail with obstacles yes.
I only switch into 4 low when I'm actually wheeling.
Driving between fire road and whatnot I'm always in 2wd.
It's not ideal for the tcase to drive over ~20-30mph in 4 low.
Since you're not regeared use 4 low to take some of the load off the transmission.
IE: if you have any inclines etc use it.
 
A

Alkihaul

New member
My trans still ran hot after I installed a cooler too. Turned out my engine was running hotter then it should so the transcooler wasn't able to cool well enough. I had a stuck thermostat, fixed that, still ran hot. I ended up dumping my coolant, and flushing my rad from both ends with a hose. Then I took the fan off and back washed the radiator fins - the water was brown. Then took the plastic cap off the top of the rad and washed behind the A/C condensor and the radiator, more brown water.

Now my Jeep runs cool as ever, can even blast the A/C in hot weather (which will effect your cooling by heating up the condenser in front of the radiator), 2 or 4 High climbing long back road hills, which used to cook my engine temps.

Another thing I found was when I pulled my fender liners, my trans temp went down 5 degrees or so, but my engine temp went up a couple degrees (I monitor both on a Trail Dash). Must just be the way in airflow change. Nothing significant but now my engine sits around 103-104 instead of 100 bang on.

TLDR: Clean the radiator, front, back, inside, really good.
 
KYRubi

KYRubi

New member
Alkihaul said:
My trans still ran hot after I installed a cooler too. Turned out my engine was running hotter then it should so the transcooler wasn't able to cool well enough. I had a stuck thermostat, fixed that, still ran hot. I ended up dumping my coolant, and flushing my rad from both ends with a hose. Then I took the fan off and back washed the radiator fins - the water was brown. Then took the plastic cap off the top of the rad and washed behind the A/C condensor and the radiator, more brown water.

Now my Jeep runs cool as ever, can even blast the A/C in hot weather (which will effect your cooling by heating up the condenser in front of the radiator), 2 or 4 High climbing long back road hills, which used to cook my engine temps.

Another thing I found was when I pulled my fender liners, my trans temp went down 5 degrees or so, but my engine temp went up a couple degrees (I monitor both on a Trail Dash). Must just be the way in airflow change. Nothing significant but now my engine sits around 103-104 instead of 100 bang on.

TLDR: Clean the radiator, front, back, inside, really good.
Click to expand...

Does yours actually run hotter with the AC on? If my engine temp goes above 205 or transmission goes over 160, I can usually just turn on the AC and get them to come back down. This is with a 2011 3.8 JKR auto with 37" tires, 5.13 gears, and an auxiliary transmission cooler.
 
fiend

fiend

Caught the Bug
KYRubi said:
Does yours actually run hotter with the AC on? If my engine temp goes above 205 or transmission goes over 160, I can usually just turn on the AC and get them to come back down. This is with a 2011 3.8 JKR auto with 37" tires, 5.13 gears, and an auxiliary transmission cooler.
Click to expand...

Turning on the AC cools the engine down? Never heard of that, but if it works for you then go for it.

I have found that turning off the AC and putting the heater on full helps cool the engine. The heater core is just a mini radiator after all.


Sent from my iPhone using WAYALIFE mobile app
 
KYRubi

KYRubi

New member
fiend said:
Turning on the AC cools the engine down? Never heard of that, but if it works for you then go for it.

I have found that turning off the AC and putting the heater on full helps cool the engine. The heater core is just a mini radiator after all.


Sent from my iPhone using WAYALIFE mobile app
Click to expand...

Definitely works on mine, especially at low speeds in traffic or while wheeling. My guess is that it turns on the cooling fan at high speed instead of waiting for the engine to get to the trigger point. Also, the highest engine temp I've ever seen on mine was 219 with a transmission temperature of 190 while towing 2000 pounds up a long hill at about 65 mph in 90 degree weather. By default, I don't think it sets the cooling fan to its highest speed until the engine is actually hotter than that.
 
jeeeep

jeeeep

Hooked
Are you disabling Overdrive when you're offroad?
2010, 3.8, 37s had my tranny overheat once on the trail. that's when I discovered the shop that installed my PSC Hydro assist had removed my Factory transmission cooler.
Running an aftermarket cooler and haven't had any issues since. usually run with the AC on, 2 or 4 wheel High and 4lo as needed, but always with the overdrive off.
 
You must log in or register to reply here.
Top Bottom