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42RLE transmission overheating

Unitize

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Hello all, so for the past several months I’ve been having the exact same problem with my transmission, it’s over heating. I had the zone 4.25 inch lift put on and put on some 33x12.50 master craft mud tires and everything seemed good for a while then I noticed the check engine light came on. It went away for a while but when it came back on the Jeep stopped shifting gears and went into limp mode. I’ve had it to the same shop over and over again over the past few months, they’ve re-built the transmission, replaced the entire cooling system in the Jeep and even replaced the radiator and added a second one just for the transmission. I’ll have it back for a few weeks and then drive it too like and it’ll over heat again and stop working. I’ll let it sit for about an hour to cool off and then it’ll work again for a while then stop. Any thoughts?
 

Chris

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How do you know it's overheating? Do you have a transmission temp gauge that you've added? If so, what temps is the transmission running at?
 
OP
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How do you know it's overheating? Do you have a transmission temp gauge that you've added? If so, what temps is the transmission running at?
I’m just going with what the shop has been talking me to be honest. They’ve had it about 6 times within the last few months because every time they “fix” it, it stops working again. I can’t take it anywhere else because no one will touch it since the work is all under warranty with the place it’s at now. The reason they believe it’s over heating is because once it goes for so long and reaches a certain temp, that’s when it stops shifting gears. If it sits and cools, it shifts fine. I believe the last time they looked at the temp they said the transmission was at around 240-250 degrees but that was 3 times ago.
 

Chris

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I’m just going with what the shop has been talking me to be honest. They’ve had it about 6 times within the last few months because every time they “fix” it, it stops working again. I can’t take it anywhere else because no one will touch it since the work is all under warranty with the place it’s at now. The reason they believe it’s over heating is because once it goes for so long and reaches a certain temp, that’s when it stops shifting gears. If it sits and cools, it shifts fine. I believe the last time they looked at the temp they said the transmission was at around 240-250 degrees but that was 3 times ago.
Something doesn’t add up. If the radiator is new and they added an aftermarket transmission cooler, the temps shouldn’t be seeing those levels. Which means they are either lying, or something else is wrong with the transmission itself.

It could be something as simple as the transmission fluid level not being full, or the wrong transmission fluid is in it.
 

Chris

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Considering all that was replaced, it's either one of those things or a plugged transmission line (not sure how) or maybe a shop that should be avoided.
Yep, all we can do is sit here and guess, but all in all it sounds like this shop doesn’t sound like they know what they are doing.
 
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Yep, all we can do is sit here and guess, but all in all it sounds like this shop doesn’t sound like they know what they are doing.
It’s hard to say to be honest. They could be lying to me and doing nothing for the weeks they have it at a time. I have it at a different shop now just to look it over and see if they see anything. One place I talked to asked me about the lift because the problems didn’t start until I had it put on, they said maybe it needs a SYE since I went for a t-case drop instead. I’m not sure if they could be the cause or not though
 

Chris

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It’s hard to say to be honest. They could be lying to me and doing nothing for the weeks they have it at a time. I have it at a different shop now just to look it over and see if they see anything. One place I talked to asked me about the lift because the problems didn’t start until I had it put on, they said maybe it needs a SYE since I went for a t-case drop instead. I’m not sure if they could be the cause or not though
I can't see how a lift would have anything whatsoever to do with the transmission overheating. The transmission overheating means that the fluid is getting to hot because it's either not circulating correctly, doesn't have enough fluid in it (are they using the proper method to check the fluid level), or it has the wrong fluid in it to begin with.

Either that or the temperature they are reading is inaccurate and there is another issue with the transmission such as a bad sensor that just thinks it's overheating.

I'd be curious what the other shop has to say.
 
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I can't see how a lift would have anything whatsoever to do with the transmission overheating. The transmission overheating means that the fluid is getting to hot because it's either not circulating correctly, doesn't have enough fluid in it (are they using the proper method to check the fluid level), or it has the wrong fluid in it to begin with.

Either that or the temperature they are reading is inaccurate and there is another issue with the transmission such as a bad sensor that just thinks it's overheating.

I'd be curious what the other shop has to say.
They did say they replaced the sensor and thermostat as well as the water pump just to make sure it was all working right (they did those for free because of the warranty) but apparently it hasn’t worked. This does give me some things to point out though if I have to take it back to the other place. I’ll post an update once I find out more, thank you.
 

Chris

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They did say they replaced the sensor and thermostat as well as the water pump just to make sure it was all working right (they did those for free because of the warranty) but apparently it hasn’t worked. This does give me some things to point out though if I have to take it back to the other place. I’ll post an update once I find out more, thank you.
Yes, definitely do let us know what they find. I'm curious myself.
 
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Yes, definitely do let us know what they find. I'm curious myself.
So quick update, I got the call from the other shop today. They told me my lift was not put on right. The motor mount that was installed wasn't set correctly and the pipes that connect the radiator to the transmission were bent out of place and were up against the catalytic converter, causing the coolant to be heated before it even got to the transmission, which is why it would take it a while to overheat. This is just what the new shop told me, not sure if that can cause it or not but they said the custom pipes they'll have to install plus labor will be about $500. Wanted to get your opinion on it.
 

MountaineerTom

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$500 for transmission lines? Does that include making them and installing? Seems kind of high, but if you have not other choice...

I hope it solves your issues.
 

Chris

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Yes they are custom making them and installing them
If they are custom making lines for it, including the labor and new fluid, I think that price is actually about what I would expect it to be.

Glad they figured out the issue. To be honest, this isn't something I had even thought about, but now that I think about it, it makes perfect sense how this could be happening.
 

Jerry Bransford

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So quick update, I got the call from the other shop today. They told me my lift was not put on right. The motor mount that was installed wasn't set correctly and the pipes that connect the radiator to the transmission were bent out of place and were up against the catalytic converter, causing the coolant to be heated before it even got to the transmission, which is why it would take it a while to overheat. This is just what the new shop told me, not sure if that can cause it or not but they said the custom pipes they'll have to install plus labor will be about $500. Wanted to get your opinion on it.
Sounds about right to me, that new shop seems to be pretty astute on figuring out problems.
 

Irun

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Even with the new lines, do yourself a favor and add a transmission cooler. The 42RLE is known for running hot, especially when run in 4H, or if you run larger tires, but don't change the gearing. JKs also ran the 42rle up through 2011 and they were notorious for transmission overheating. Jeeps fix for the 2007 - 2011 42RLE was to install a hot oil light, which was lame. Also, the best way to keep an eye on the transmission is to install a temperature gauge.

All that said, I know Jerry did a write up on the Derale cooler, which is a good option. I didn't go down this path, because on the East Coast we have more mud to contend with and I didn't want to install a cooler inside the vehicle. My personal choice was a B&M stacked plate design. Wheeling all day in 90+ degrees, in WV, the highest temperatures I saw was 165 degrees.

https://www.amazon.com/70264-SuperCooler-Automatic-Transmission-Cooler/dp/B000CIIDZE/ref=sr_1_1?keywords=B&M+70264&qid=1575462212&sr=8-1


 
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mrblaine

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So quick update, I got the call from the other shop today. They told me my lift was not put on right. The motor mount that was installed wasn't set correctly and the pipes that connect the radiator to the transmission were bent out of place and were up against the catalytic converter, causing the coolant to be heated before it even got to the transmission, which is why it would take it a while to overheat. This is just what the new shop told me, not sure if that can cause it or not but they said the custom pipes they'll have to install plus labor will be about $500. Wanted to get your opinion on it.
They are jerking you around. There is no way the lift affected the trans cooler lines. They may not understand that the lines from the factory go behind the exhaust below the small converters. I would have to know exactly where they plan to reroute them before I approved the work since I believe they are pretty much full of shit and don't understand how the lines are supposed to be.

I haven't seen mention of your gear ratio? I also haven't seen mention of an aftermarket cooler which I certainly would have explored along with a trans temp gauge long before it got this far down the rabbit hole.
 
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If they are custom making lines for it, including the labor and new fluid, I think that price is actually about what I would expect it to be.

Glad they figured out the issue. To be honest, this isn't something I had even thought about, but now that I think about it, it makes perfect sense how this could be happening.
Another update. I got my car back and got the new lines in. Worked great for about a day then I had to drive about an hour away and as soon as I got into slow traffic I felt a kick while I was stopped and then the Jeep wouldn’t accelerate like it should (it hesitated but the Rpms went up) and wouldn’t shift gears. So it’s doing the exact same thing it was doing before. I let it sit for about an hour then it started to shift again. Any ideas?