KJ Renegade Transmission Overheating

Hi all, I am new to the forum, thanks for such a great resource.

I have been reading about the transmission issue posts for a few days now and can’t seem to find a post that has my symptoms.

I have a 2005 Renegade KJ 3.7L v6 Auto with 97000km (60200 miles), It does have the tow package with the mechanical fan. I have had this Jeep for around 5 years now with full service well looked after.

The transmission light comes on when driving in the hills for +- 30min (yes O/D is off). If driving on the beach, transmission light comes on in +- 10 min (tried using Gear 2 with O/D off in 4wd) this gave about 13 min before the light comes on).

It has just been for a service and driving normally highway, peak traffic etc. with no problem. The electric fan does work as I can hear it when its kicked on. The average temperature in Queensland Australia is 24deg – 33deg (75.2F – 91.4F).

The KJ is stock standard in every way, I am just about to do some upgrades like a 2.5 inch lift, JBA upper Control Arms, ARB Bar + Winch, Snorkel kit and Free Flow exhaust. (other recommendations would be greatly appreciated).

But the first thing I must get resolved is the Transmission over heating issue.

Thanks in advance for any advice / input.

Maybe try cleaning out the radiator? Could be packed full of crap. Just a though.

Thanks I will certainly try that, at this point I will try anything to get it sorted. The Auto trans "specialist" said replace the entire cooling system, I don't believe the entire system is not working as the car is fine in normal driving. Any sort of cleaner / radiator flush you recommend?

Did it just start doing this all of a sudden or has it been since new ?
depending on the sand ( loose or hard packed) it could be that you need to be in low range instead of just 4WD or something. Not knowing the conditions fully makes it harder to tell what to do. Here for example if you are going real slow on several hills pulling down the engine/ lugging it then that will heat the transmission up quickly when in 4high and not 4 low

It has been doing this now in the hills (tarmac) for the last few months more and more, It did it the first time about 3 years ago when driving up to the ski slopes also tarmac. With regards to the speed in the hills (tarmac) with OD off, the speed is average 55 - 60km (34 - 40 mph).

With regard to the sand it is soft loose beach sand. I had a few other 4wd trucks and never needed to even consider low range for the beach.

Here is a pic of the beach sand conditions:

This is a total thread hijack, but I want your side marker lights :Big Laugh:

As for the trans overheating, I'd try a complete trans fluid flush, refilled with ATF+4 ONLY. Could be the front trans cooler isn't allowing proper fluid flow through the cooler - and any overheating is a problem with these transmissions.

Does your KJ have the in-rad trans cooler? If so there could be an issue with the cooling system not doing it's job cooling the trans fluid. Have you flushed/filled the cooling system? Be sure to use HOAT-type coolant or there will be problems down the road.

Since you're coming into summer down under I can see why you want to take care of this now.

Bob

2x on what TwoBobsKJ said!

(I was writing the same as his, but I edited my post just in time before submitting...).

PS: SIRRuS, nice Rig, but she really needs a lift (I mean, the vehicle...). Nice beach.

Thanks Bob and Diyman, and thanks for the compliments on the rig.

Yes it does have the in-rad trans cooler but i think you guys are all right in saying that it could be clogged.

I went down to our local Jeep off-road specialist as this was bugging me after I wrote the post. In fact I spent my entire day sorting this out. Here is where we stand, I have gone from trying to resolve the overheating to spending far too much on a complete overhaul.


Jeep is booked in for the 8th, getting a :

CRDSTN 2.5" Lift System Installed
Als Upper A Arms
New Lower Clevis Brushes
After Market Transmission Oil Cooler Mishimoto
Complete Flush, Fluid Filter replacement
Scan Gauge II install
ARB Bar Install

I was gona say hope the wife will be okay with this, but then i thought, well now I can take her to the beach again so she will be fine with it, its a shame that we are 10min from that beach (33KM of beach driving and camping spots) and cant use it cause we over heat.



The Jeep Specialist guarantees that after he replaces the fluids, filters and new oil cooler that the trans temp will not go over 75deg (167 F) In fact that’s the reason for the Scan Gauge II.

I will report back with new photos of how the KJ looks with its new kit on and how the cooler performs.

Thanks to all for the help and advice.

Scan guage wont tell you the trans temp. Isnt an option for our jeeps.

I was going to ask about your cooler, because my '05 has a separate transmission cooler, not in-rad. It's low and sits in front of the rad.

It took one and a half cans of ****** line cleaner to blow the crap out of the cooler, with the cooler off the vehicle, when I replaced my ****** recently.

Leeann said:

I was going to ask about your cooler, because my '05 has a separate transmission cooler, not in-rad. It's low and sits in front of the rad.

It took one and a half cans of ****** line cleaner to blow the crap out of the cooler, with the cooler off the vehicle, when I replaced my ****** recently.

Click to expand...

Wow! Was it clogged with gummy trans fluid or other "stuff?"

I've heard that if the trans cooler isn't flushed well when a new/rebuilt ****** is installed that gunk/debris in the cooler will trash the new trans. Tell us what came out of the cooler - I'm always up for a good trash story :evil:

Bob

Pics are in my Member Journal thread - here: http://www.jeepkj.com/forum/f222/05-renegade-fixer-upper-54076/

Mostly chunks of clutch material. Teeny-tiny-itty-bitty little slivers of aluminum, essentially aluminum dust (didn't stick to the magnet) with one or two larger chunks.

That's about it. It's just hard to blow stuff out because of the design and because the feeds point down. We took it off, turned it sideways and blew in the top line and out the bottom - into a 2-liter. The bf is an HVAC master, so he's used to cleaning condenser coils and such. He said no way will the cleaner make it to the top half of the cooler if we didn't take it off the truck.

And I'm convinced that's what trashed the ****** that was in the Jeep when I bought it - a known-good used ****** bought cheap and installed when the torque converter puked itself. Two weeks later, the good one is trashed…hmmmmm….

Not just the gunk in the cooler making it into the ****** and sticking stuff, but the reduced cooling. It was January in Michigan (and a snowstorm, to boot), but it still overheated and ate itself.

Oh - and the warranty on the good used ****** I installed was no good if I didn't have receipts for at least one can of ****** flush. I bought 2, just in case (fortunately!).

Hi Leeann, I had another look and I do have a small radiator in front of the normal radiator but it is really low so I missed it, its next to the very tiny aircon radiator, is that the one you are talking about?

Its a bummer about the scan gauge not monitoring the ****** temp, I decided to go with a wifi ODB2 as i got an old iphone that i can dedicate to dashcommand At least that will give me a better indication of temps and errors etc.


Thanks for all the input everyone, I feel confident that this will now be resolved. The flush ****** oil replacement / mishimoto cooler replacement should hopefully solve those issues now.

That's the one. Same width as the radiator, but not very high.

JeepJeepster said:

Scan guage wont tell you the trans temp. Isnt an option for our jeeps.

Click to expand...

Thats a bummer, ahhh well I decided to with the wifi OBD2 as I have a spare iphone i can dedicate to dashcommand

Leeann said:

That's the one. Same width as the radiator, but not very high.

Click to expand...

yeah exactly, but its really low, can hardly see it, The bumper would stop all airflow to it.

Looks like this off the truck...

And on the Jeep

Yeah thats it, the one they are replacing it with sometihng that looks like this and will have a fan on it too:



Its about 3 times the area of the little one.

TwoBob, Sorry for my mistake earlier, I thought it was an in Rad Cooler originally.