Over Heated Tranny: Update 4/21

scoobysnax · **Posted:** Tue Apr 20, 2010 12:37 pm

Did you air down? Regardless of oversized tires or stock sized tires you need to air down when on the sand. I run my tires around 37 psi on the street and when I'm on the beach I've found 20 to be ideal and I always use 4L with the OD locked out. I can't find the link right know but there is a site you can look up that explains the science behind deflating the tire and how it makes a big difference.

Fulltimer · **Posted:** Tue Apr 20, 2010 5:42 pm

No, I didn't air down. Should have though. After all I carry CO2 for doing just that. Mental fart I guess.

Terry

LibertyFever · **Posted:** Tue Apr 20, 2010 6:14 pm

The automatic transmission on my 04 Liberty occasionally overheats while I'm on the trails even with an external transmission cooler. I think part of my problem is not being in 4WD Lo and I'm still learning how to drive an automatic on the trails :oops:

Fulltimer I may have missed it within all these replies but do you have a transmission cooler? and electric or mechanical rad fan?
If you don't yet have a transmission cooler I suggest you get one and maybe use 4WD Lo on the trails.

I too like the 02 Liberty radiator with the internal transmission cooler. If I ever blow mine I'm going to install one.

Personally I dislike the dashboard's idiot light that comes on when the transmission overheats. I plan to install a temperature gauge like this;
http://nsjc.proboards.com/index.cgi?board=fab&action=display&thread=31424

kskj · **Posted:** Tue Apr 20, 2010 6:25 pm

dieselenthusiast wrote:

In other words, Troy is saying that Fulltimer can buy a 2002 Jeep Liberty radiator (with the built-in cooler) and have it installed in his 2005 KJ. This would help control the temperatures spikes.

That is what I did. My trans light would come on when I was in colorado climbing off road in altitude. I put in a 2002 radiator with trans cooler in line with the stand alone trans cooler that the 2004 already had. Last year At the Ouray safari it did not overheat at all even at over 13,000 feet. (It was Troy's suggestion). And it worked great. :mrgreen:

JeepinJarhead03 · **Posted:** Tue Apr 20, 2010 6:30 pm

is it the 42RLE volume of fluid as well maybe? more so than directly only being a result of the the cooler in the radiator

how much less fluid does the 42 have compared to the 45 or are they for all intents and purposes equal in fluid volume?

Miles and miles and miles of baby powder consistency sand and have only used 4-lo maybe 5% of the time

but i do have the 45 and an 03 with all sorts of cooling, excluding a mechanical fan

When i lived on the beach for a week earlier this year i did end up putting it in 4-lo and leaving it because i actually managed to get all 4 wheels tractioned in and partially dug in on a 60 degree incline with the tranny pan on the ground, tight enough that the tires weren't turning with slight pressure on the gas and a shift to 4-lo resolved that entirely, but then it would idle away from me down the beach (very - slowly) if i got out with it in gear to pick up firewood lol

JL Rockies · **Posted:** Tue Apr 20, 2010 6:32 pm

ghost ridin'

tjkj2002 · **Posted:** Tue Apr 20, 2010 10:40 pm

JeepinJarhead03 wrote:

is it the 42RLE volume of fluid as well maybe? more so than directly only being a result of the the cooler in the radiator

how much less fluid does the 42 have compared to the 45 or are they for all intents and purposes equal in fluid volume?

Miles and miles and miles of baby powder consistency sand and have only used 4-lo maybe 5% of the time

but i do have the 45 and an 03 with all sorts of cooling, excluding a mechanical fan

When i lived on the beach for a week earlier this year i did end up putting it in 4-lo and leaving it because i actually managed to get all 4 wheels tractioned in and partially dug in on a 60 degree incline with the tranny pan on the ground, tight enough that the tires weren't turning with slight pressure on the gas and a shift to 4-lo resolved that entirely, but then it would idle away from me down the beach (very - slowly) if i got out with it in gear to pick up firewood lol

The fluid capacity is within 1qt or so of each other(13qts for 42RLE,I believe,and 14qts for the 45RFE).The major difference is the trans cooler between the 2,The 45RFE's cooler is much more effective at keeping the fluid temps in check.

Now some will think that a engine overheating has nothing to do with the trans,more so when the trans has a stand alone cooler but heat transfer comes into play(as they are bolted together and the trans cooler is in from of the radiator) and they in fact do have a direct effect on each other.

mag03kj · **Posted:** Tue Apr 20, 2010 11:18 pm

Well stupid ? but whats the 02 trans cooler look like or how is it diff?

kskj · **Posted:** Tue Apr 20, 2010 11:20 pm

THe 02 is in the radiator and newer kj's it is a separate cooler.

mag03kj · **Posted:** Tue Apr 20, 2010 11:25 pm

oh ok well i got a newer one then!

Fulltimer · **Posted:** Wed Apr 21, 2010 9:28 am

Here is what Chrysler said: " Cooling fan is not directly tied to trans. temp., but trans. cooler can effect coolant temp. and cause fan to come on under certain conditions." In other words the tranny can over heat and the electric fan won't necessarily come on to cool it down. Kinda dumb if you ask me! The mechanic suggested putting in a manual switch to turn on/off the fan. That sounds like a good idea.

Terry

Jeepjeepster · **Posted:** Wed Apr 21, 2010 9:45 am

Usually I unhook the A/C compressor and just turn the A/C on. You can control the cooling fan by turning the A/C on and off inside but the compressor will not kick on since its unhooked. You shouldnt be using the A/C on the trails anyway.

This is why its a good idea to get a mechanical cooling fan. Its always pulling at least some air through the radiator, even when its not engaged. If the electric cooling fan isnt on then theres pretty much no air being pulled through the cooler at low speeds.. Usually on a trail your speeds are very low, thus you have an over heated tranny.

Budke · **Posted:** Wed Apr 21, 2010 10:03 am

Terry, if you put a manual switch in let me know how its done so I can do the same!

Fulltimer · **Posted:** Wed Apr 21, 2010 12:06 pm

Budke wrote:

Terry, if you put a manual switch in let me know how its done so I can do the same!

It shouldn't be hard. I'll use a toggle switch. Right now that is taking a back seat to other things. No hurry at all.

Terry

JL Rockies · **Posted:** Wed Apr 21, 2010 3:09 pm

I use the AC on the trails all the time. It gets hot in MOAB and if you're not trail leader, it cuts down on dust getting on the mad custom interior. I believe the trans cooler for the CRD is also built in....

rhinocharg · **Posted:** Wed Apr 21, 2010 5:51 pm

Jeepjeepster wrote:

Usually I unhook the A/C compressor and just turn the A/C on. You can control the cooling fan by turning the A/C on and off inside but the compressor will not kick on since its unhooked. You shouldnt be using the A/C on the trails anyway.

That is a great idea, I never thought of that.

LibertyFever · **Posted:** Wed Apr 21, 2010 7:09 pm

Fulltimer wrote:

Here is what Chrysler said: " Cooling fan is not directly tied to trans. temp., but trans. cooler can effect coolant temp. and cause fan to come on under certain conditions." In other words the tranny can over heat and the electric fan won't necessarily come on to cool it down. Kinda dumb if you ask me! The mechanic suggested putting in a manual switch to turn on/off the fan. That sounds like a good idea.

Terry

WoW you guys are some smart to think of these ideas.

I wouldn't be surprised if my transmission is overheating and the electric fan isn't being turned on. Everything runs through the BCM so turning the A/C on simply fools the BCM into turning on the electric fan.

I'm either going to put a manual switch in for the fan or disconnect the A/C. Just how often do you really need A/C here in Canada?

jnaut · **Posted:** Wed Apr 21, 2010 7:38 pm

Fulltimer wrote:

Here is what Chrysler said: " Cooling fan is not directly tied to trans. temp., but trans. cooler can effect coolant temp. and cause fan to come on under certain conditions." In other words the tranny can over heat and the electric fan won't necessarily come on to cool it down. Kinda dumb if you ask me! The mechanic suggested putting in a manual switch to turn on/off the fan. That sounds like a good idea.

I've been lucky so far and never had a transmission overheat- even on some serious altitude climbs, and I use 4hi where the trail is fairly easy going, but I'm getting wheel slip on 2wd. However, if I regularly saw transmission heat issues, I'd probably just install the mechanical heavy-duty cooling solution. Although a switch on the electric fan does sound kind of sexy.

jnaut · **Posted:** Wed Apr 21, 2010 7:43 pm

JL Rockies wrote:

I use the AC on the trails all the time. It gets hot in MOAB and if you're not trail leader, it cuts down on dust getting on the mad custom interior. I believe the trans cooler for the CRD is also built in....

Heh, I feel you. I did a little wheeling last year in Eastern Washington where summer time temps are quite a bit warmer than here in Western Wash. I avoid using my AC on the trail to cut down on the added heat, really, I almost never use it. Even when I'm uncomfortable. But on the Eastern Wa. trip I just got too hot, finally cheated and turned on the AC on some of the flat trail areas.

However, most of the day my windows were down to cope with the heat. One thing they have in Eastern Wa that they don't have here in West is that super-fine dust like the soldiers describe in Iraq. When I got back I had what amounted to Talcum powder on every surface inside the jeep. It was in the vents, on the door jams in the carpets, everything. god it sucked. Luckily I have leather so it didn't 'embed' into my seats. That was the one part of the truck that was easy to clean. I was still blowin' dust out of the vents for 2 months after.

JL Rockies · **Posted:** Wed Apr 21, 2010 10:21 pm

jnaut wrote:

JL Rockies wrote:

I use the AC on the trails all the time. It gets hot in MOAB and if you're not trail leader, it cuts down on dust getting on the mad custom interior. I believe the trans cooler for the CRD is also built in....

Heh, I feel you. I did a little wheeling last year in Eastern Washington where summer time temps are quite a bit warmer than here in Western Wash. I avoid using my AC on the trail to cut down on the added heat, really, I almost never use it. Even when I'm uncomfortable. But on the Eastern Wa. trip I just got too hot, finally cheated and turned on the AC on some of the flat trail areas.

However, most of the day my windows were down to cope with the heat. One thing they have in Eastern Wa that they don't have here in West is that super-fine dust like the soldiers describe in Iraq. When I got back I had what amounted to Talcum powder on every surface inside the jeep. It was in the vents, on the door jams in the carpets, everything. god it sucked. Luckily I have leather so it didn't 'embed' into my seats. That was the one part of the truck that was easy to clean. I was still blowin' dust out of the vents for 2 months after.

Ours is red.

Over Heated Tranny: Update 4/21

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