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To make a long story short, I have had several TJ's over the years and this is my first JKU. I bought it with a salvage title due to front end damage. Although it is a salvage title, it only has 35k miles.So far, I have replaced the radiator, AC condensor, right side catalytic converter, rebuilt the transmission and added some accessories (i.e. 12000lb winch with cover, front and rear steal bumpers, light bar on front stinger and 33" BFG's). Since the transmission was rebuilt, the jeep seems to not be shifting always when it should and runs hotter than it ever did before. For example, sometimes it will go up to 5k RPM's before it will shift or I have to let off the gas to get it to shift. My mechanic has gone through the entire cooling system since the transmission was put in. I replaced the fan/modular kit because it seemed to be shutting off at higher speeds when I was heading up the mountains. It also runs slightly over the middle on the temp when I am just running around town. What I am trying to figure out is if the transmission rebuild could be causing the jeep to run hotter for some reason and not always shifting the way it should. My mechanic says everything has been checked and it is not the cooling system. He is also the one that put in the tranny so what now? I removed the cover on the winch and engine cover and folded down the new light bar to promote more air intake through the radiator which still did not help. Could the 33" tires be causing any issues (I can't imagine with that slight of change from stock that it would be)? I am at a loss. Please help!
 

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any 42rle automatic jeep jk between '07 and '11 with 3.8l needs a good, higher gvw auxiliary transmission cooler added . Even some of the better factory provisioned auto from '12 and up with pentastar 3.6l motors benefit from sux tranny cooling but not like the necessity of them being installed on the earlier JKs.
I , too, would need to know why the tranny was rebuilt and wtf was done to the ecu and tipm as far as programming and flashing after thectranny was rebuilt, what did rebuild consist of , how many other trannies had this guy repbuilt , what codes it's throwing , what actual temp the PID is displaying for the tranny temp and where you're measuring from , on and on etc....

that's a lot of variables and important data for a forum diagnosis like you're requesting, OP. You've not even thrown the year of the darn jeep out, pal.

:jeep2:
 

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To make a long story short, I have had several TJ's over the years and this is my first JKU. I bought it with a salvage title due to front end damage. Although it is a salvage title, it only has 35k miles.So far, I have replaced the radiator, AC condensor, right side catalytic converter, rebuilt the transmission and added some accessories (i.e. 12000lb winch with cover, front and rear steal bumpers, light bar on front stinger and 33" BFG's). Since the transmission was rebuilt, the jeep seems to not be shifting always when it should and runs hotter than it ever did before. For example, sometimes it will go up to 5k RPM's before it will shift or I have to let off the gas to get it to shift. My mechanic has gone through the entire cooling system since the transmission was put in. I replaced the fan/modular kit because it seemed to be shutting off at higher speeds when I was heading up the mountains. It also runs slightly over the middle on the temp when I am just running around town. What I am trying to figure out is if the transmission rebuild could be causing the jeep to run hotter for some reason and not always shifting the way it should. My mechanic says everything has been checked and it is not the cooling system. He is also the one that put in the tranny so what now? I removed the cover on the winch and engine cover and folded down the new light bar to promote more air intake through the radiator which still did not help. Could the 33" tires be causing any issues (I can't imagine with that slight of change from stock that it would be)? I am at a loss. Please help!
Post a picture of your front end. Your winch is probably blocking too much air flow. I have the same issue.
HERE is mine. all that = too much disruption in the air flow. also removing the engine cover I did not notice any difference really. might as well just leave it on.
 

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Post a picture of your front end. Your winch is probably blocking too much air flow. I have the same issue.
HERE is mine. all that = too much disruption in the air flow. also removing the engine cover I did not notice any difference really. might as well just leave it on.
Same thought here regarding grille obstruction.

Did you put the winch, winch cover, and "angry grille" on at the same time? How did those mods correlate with the coolant system changes?

First TX summer underway with my LS3 and I have already made several modifications to the front end / cooling package based upon seeing what air flow characteristics were doing to operating temps.

A camera and some flyers on the grille would probably show zero flow at anything over 40 MPH based upon your profile pic. This will result in high temps and burning up fans.
 

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Same thought here regarding grille obstruction.

Did you put the winch, winch cover, and "angry grille" on at the same time? How did those mods correlate with the coolant system changes?

First TX summer underway with my LS3 and I have already made several modifications to the front end / cooling package based upon seeing what air flow characteristics were doing to operating temps.

A camera and some flyers on the grille would probably show zero flow at anything over 40 MPH based upon your profile pic. This will result in high temps and burning up fans.
Never thought of actually testing it like that. I need to do that one day. Thankfully without the winch cover on i generally don't move from middle. Only going up "mountains" do I notice it going too hot.
 

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I have 12k on a poison Spyder bumper. Look in profile. Never overheats. In fact runs just under a half. Only warms up at high speed steep inclines.
Unlikely the winch alone. Never covered one though. Never understood the logic, but it could act like a large plastic bag I guess.
I'm voting with the trans cooler crowd.
 

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Yes it was re-installed. The jeep is a 2013 3.6L and the reason the transmission was rebuilt is because when it was in the front end collision, the transmission line to the radiator was damaged and leaking fluid. Not sure if the previous owner drove it like that with the fluid being low before we bought it or not. We fixed the line but it never seemed to shift properly. Then we checked the fluid levels and added some transmission fluid which did not help at that point. Then one day, it would not shift into gear or go anywhere. I had it towed to the mechanic and he said the first three clutches were shredded, hence the rebuild. I am not sure how much experience the mechanic had at rebuilding but didn't seem to be an issue. They do not have a specialty on working with jeeps but do have some of there mechanics who own jeeps of their own and are familiar.
 

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Discussion Starter #9
I did put the accessories on all at the same time and did not seem to have any running hot issues before the transmission was rebuilt but then again, the outside temperature was also not as hot. Has been in the mid-90's many days. I would like to put my new 35's on it but I understand that may effect performance and do not want to put more strain on it to cause it to overheat. Does anyone think that installing an extra fan with a toggle switch would help in cooling it down when I notice the temp is rising and if so, where would be the best inconspicuous place to install it? I don't want to burn out another fan, that was $900!
 

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Probably should have asked in previous post but, what are you using to set the corrected tire size in the PCM\TCM (Superchips, ProCal, etc.)?
 

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Here is a closer pic of the front. I did take off the winch cover but there is a small motor box that sits atop the winch that might still obstruct airflow. As far as cooling modifications, I have not made any other than replacing the fan that supposedly was shutting down at higher speeds when the temp when up. This was according to the mechanic who said the fan modular was bad so I had to replace the entire thing. Seems to be consist with one of the forum responses about burning out fans, no? Removing the winch cover and engine cover did not really do much for the temp running high. Do anyone think that the temp running higher would also cause it not to shift properly with the RPM's occasionally going up to 5k before shifting? Any suggestions for modifications to the cooling system if the problem is airflow obstruction?
 

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Haven't really done anything as far as correcting the tire size in TPM. Put the 33" tires on and drove it. I didn't suspect that would make much of a difference from the original size. I am going to be upgrading to the 35" tires, what should I do as far as correcting the tire size? Never really had these issues with my old TJ. Seems the newer JK's are a bit more complicated and this has been a learning process. I will tell you that my TPMS light has been coming on and off so perhaps that is why? Hopefully I don't sound like a complete and total moron with all of these posts. Just a girl and her jeep! Thanks for the help!
 

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Ok.. off the high temp to the TPMS and shift point correction. You need a ProCal or Superchip (looks like a tuner but it's not). The pro cal looks like those cheap wanna be programmers of the 90s. Like a small Atari cartridge.
Now that I've dated myself, these will turn off your tire pressure monitoring system that apparently isn't reading correctly or is absent (sensors) in the new tires.
With the device you also need to adjust or "tell" the jeep what size tire you have as you've deviated from stock. You need to enter true size using a phone gps or something, not the jeep nav.
Then tell it what ring and pinion size. After that, the trans and engine are up to snuff on what you've done.
Kinda made it simple for you. Hope you understand
 

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As far as your pick, IMHO I'd rip all that stuff off. The mad thing, the winch cover and leave em off.
Get the corrected settings with a programmer/procal/flash cal and THEN figure out your cooling issues. The fan is really for high temp cool down, not continuous use. Wrong direction. Look at trans cooler, radiator, thermostat, radiator hoses, mud and crap in fine. Everything
 

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Like Tierhog said, the JK must be programmed for any tire/gearing change. It is annoying how little a 33" tire can change a big ol Jeep.

Getting your transmission hot will effect shifts. Once I changed hoods, my problems when away. Another Jeep I changed out the inner fenders to vented ones and the same issue went away.

Another little thought but very important is the plastic shroud pieces around your radiator. Are these still there after the rebuild? You would not believe how critical that junk is to the engine and trans cooling.
 

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Discussion Starter #16
Thank you all for the advice! I will try the programming, removing the angry grill and replacing with stock and removing the winch cover. Then I will see where that leaves me.
 

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Ok, let's take a step back here. The transmission is not shifting properly. Do we know why? It could be the larger tire size. Can you put the stock tires back on to rule that out? If not, get an AEV ProCal (or something else) to recalibrate the transmission to the correct tire size and gear ratio. Depending on the tools your mechanic has, perhaps he (she) can do that with a scan tool - don't know.

The transmission not shifting at the correct shift points can definitely cause your engine temps to elevate. But so can the warmer weather and driving up Floyd Hill, Eisenhower tunnel, etc.

The 2013's run stupid hot. Mine saw 240 degrees on certain grades at altitude. Are you trying to hold 70 MPH on the climbs?? And if you are solely relying on the temp gauge in the dash, you are wasting your time. Its not analog at all. It has certain presets that it goes to and stays there until a threshold is crossed - up or down. If you really want to know what your coolant temps are, you need something like an AeroForce gauge or Traildash. ( I think the traildash can reset your transmission for different tires and gears as well.)

Did your mechanic put the proper coolant back in the system? (It should be purple.) If not, that could be the cause of your issues, easily! This is a big flag - make absolutely certain he used the genuine Jeep coolant for 2013, not for 2012.

The 2013s run hotter than any of us would like to see. But after having mine gone through by the dealer under warranty (flush system to remove casting sand, then replace water pump a few months later) I am convinced it is just the way FCA programmed the damn things to run. And I believe Motech has pretty much confirmed this (but going off of memory of a post by Robbie).

If your dash gauge is running between half and 3/4 or even over at 3/4 sometimes, welcome to the club. There is nothing really to be done about it. You can't (reasonably) install an extra fan. You can't override the fan controller to turn it on sooner. (Although Robbie has hinted that he has cracked the code for doing just that. I just don't know if it is something he would provide on a non-LS converted JK.)

I don't think your winch has anything to do with it. The grill, who knows, maybe. But let's look at the obvious things first. The wrong coolant could be the culprit.
 
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