Transmission Tunnel Overheat
07-11-2018, 09:17 AM
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Year: 1991
Model: Cherokee (XJ)
Engine: 4.0
Transmission Tunnel Overheat
I recently took a trip with my gf down to see her parents (about an hour and a half drive) and about halfway through, where the e-brake handle is right above the transmission tunnel on 91 XJ got really hot. I pulled over and tried to let it cool down but had to push through anyway. The temperature on the jeep didn't rise anything above 210 (electric fan wired to a switch) but the rest of the way there and almost the entire way back, the transmission tunnel was unbearably hot. This has happened in the past when I make a long ish trip but this is the longest trip and I really noticed it. Anybody have anything like this happen? Thanks guys!
07-11-2018, 09:40 AM
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Year: 1998
Model: Grand Cherokee (ZJ)
Engine: 5.2
I recently took a trip with my gf down to see her parents (about an hour and a half drive) and about halfway through, where the e-brake handle is right above the transmission tunnel on 91 XJ got really hot. I pulled over and tried to let it cool down but had to push through anyway. The temperature on the jeep didn't rise anything above 210 (electric fan wired to a switch) but the rest of the way there and almost the entire way back, the transmission tunnel was unbearably hot. This has happened in the past when I make a long ish trip but this is the longest trip and I really noticed it. Anybody have anything like this happen? Thanks guys!
07-11-2018, 09:54 AM
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Year: 1991
Model: Cherokee (XJ)
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If you're talking about the coolant, then yes because I've changed the radiator, water pump, thermostat housing unit (took thermo out for the summer) fan clutch, and wired my electric fan to a switch. Each one was a pain in the *** because of the clean up! 
07-11-2018, 10:52 AM
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You know there is fluid in the transmission that needs to be maintained and changed right? No fluid or bad fluid equals no bueno
07-11-2018, 05:49 PM
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I was going to say, if it is abnormally hot (I could probably cook eggs on my XJ trans tunnel when I am stuck in traffic in 100*F heat), it could be your engine running lean. It would cause the EGT (exhaust gas temperature) to rise and heat the floor up.
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07-14-2018, 11:33 PM
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Year: 1991
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So I checked the trans fluid and it’s good maybe about a quart low...could it really make THAT much of a difference? Also it’s like when I’m driving down the highway.
07-15-2018, 07:57 AM
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This is common out here in the desert. Hot out with A/C on during long extended runs. And I mean just shy of lighting the carpet on fire fry an egg on it kind of hot.
07-20-2018, 09:10 AM
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So I topped it off and it’s still happening...I said something a while back about something a long the lines of a heat shield? Does anyone know if the xjs should have one or if anyone has had my problem and done one? Thanks guys sorry for the late reply
07-20-2018, 09:18 AM
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Do you think it is possible someone may have had the carpet out of that and maybe removed the insulation under there for some reason? That would do it...
07-20-2018, 09:21 AM
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Hopefully not haha but I do have some rust I want to take care of under there so it might be a good thing to look
07-20-2018, 09:25 AM
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What's the condition of your radiator? Could be the trans cooler side of it isn't doing it's job.
I stripped out my interior last summer. Up front there was a foil covered insulator maybe 18" square under the carpet. Thing is I didn't remember to reinstall it. Hasn't seemed to make a bit of difference. While the carpet was out I had to use a couple throw rugs and rubber floor mats to keep the heat under control but all in all I don't believe I'm getting the amount of heat you are.
I stripped out my interior last summer. Up front there was a foil covered insulator maybe 18" square under the carpet. Thing is I didn't remember to reinstall it. Hasn't seemed to make a bit of difference. While the carpet was out I had to use a couple throw rugs and rubber floor mats to keep the heat under control but all in all I don't believe I'm getting the amount of heat you are.
07-20-2018, 09:33 AM
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What's the condition of your radiator? Could be the trans cooler side of it isn't doing it's job.
I stripped out my interior last summer. Up front there was a foil covered insulator maybe 18" square under the carpet. Thing is I didn't remember to reinstall it. Hasn't seemed to make a bit of difference. While the carpet was out I had to use a couple throw rugs and rubber floor mats to keep the heat under control but all in all I don't believe I'm getting the amount of heat you are.
I stripped out my interior last summer. Up front there was a foil covered insulator maybe 18" square under the carpet. Thing is I didn't remember to reinstall it. Hasn't seemed to make a bit of difference. While the carpet was out I had to use a couple throw rugs and rubber floor mats to keep the heat under control but all in all I don't believe I'm getting the amount of heat you are.
I think the key in this is that the problem seems to arise during sustained long runs. Back when I was a kid out here in the desert it took me awhile to understand that when someone stopped and took a break to "let their car cool down" they were not talking about just the engine and running gear. It was the whole car floor and all! lol