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Tranny temps - how hot??

gopking

NAXJA Forum User
I've got a stock '98 XJ, I6, 4x4. I just finished installing a tranny temp gauge with the sensor installed into a sensor manifold in the tranny feed line. I have no tranny cooler. I ran then around town for about an hour/hour and half. Here is what I observed:

Highway: ~150*
City: ~195*

What I was really surprised about was how quickly the tranny heats up and cools down. Coming off the highway, it reaches temps of up to 195/200 in only about 20 seconds. When getting onto the highway, it cools down to about 150 in only about 4-5 minutes. Is that normal?

What temps are your guys' rigs runnning at; city/highway??
 
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The spec in the service manual on my 96 says that 176 is normal, I have seen the same behavior with my trans. I have a cooler, and external oil filter setup, with a temp sender in the filter housing, pretty much the same results, since setting the cooler /filter setup up, I have not seen temps over 195-200 even when dogging it up a hill someplace. in traffic on a 60-70 deg day the temps stay around 150-180, stop and go traffic will allow it to get warmer, but thats about it. Withou the cooler, I wa sgetting temps much hotter, it would go up over 200 regularly.....
 
Actually I’d say that was pretty good. I have a ’91 4x4 AW4 with the in radiator cooler and an external cooler. My temps usually run between 190 and 210. When I put it in 4 Lo the temp really climbs quickly and I’ve had the needle pegged before (250 degrees) while running up snowy hills. It’s amazing how quickly the tranny temp goes up and down. Its droped down to 170 while crusing along on the hiway. I forgot to put in the tow cooler stuff when I changer the tranny fluid last time. That stuff really does make a difference. The tranny got up to operating temp and cooled off quicker. It also ran a lower overall temp than just straight tranny fluid. Definitely worth the $15 as far as I’m concerned.
 
Art Triggs said:
The spec in the service manual on my 96 says that 176 is normal, I have seen the same behavior with my trans. I have a cooler, and external oil filter setup, with a temp sender in the filter housing, pretty much the same results, since setting the cooler /filter setup up, I have not seen temps over 195-200 even when dogging it up a hill someplace. in traffic on a 60-70 deg day the temps stay around 150-180, stop and go traffic will allow it to get warmer, but thats about it. Withou the cooler, I wa sgetting temps much hotter, it would go up over 200 regularly.....

Wow! Mine runs much hotter than that. And I live in AK!
 
At least we have a REAL mall. You guys get colder in the winter and hotter in the summer – the worst of both worlds! Just giving you a bad time. You have some pretty cool trails up there. Last time I got the tow cooler at Schuck’s. It’s about $15 and they sell it as a tranny cooler fluid supliment. It works much the same way as Water Wetter, if you’re familiar with that product. It really does help on the warm up (important in winter) and keeps it running cooler overall. The stuff is kind of weird; it heats up AND cools down faster.
 
Art Triggs said:
The spec in the service manual on my 96 says that 176 is normal, I have seen the same behavior with my trans. I have a cooler, and external oil filter setup, with a temp sender in the filter housing, pretty much the same results, since setting the cooler /filter setup up, I have not seen temps over 195-200 even when dogging it up a hill someplace. in traffic on a 60-70 deg day the temps stay around 150-180, stop and go traffic will allow it to get warmer, but thats about it. Withou the cooler, I wa sgetting temps much hotter, it would go up over 200 regularly.....


I just had an epiphany. I’m running 31” tires with the stock gears (3.55s). I’ve been told that this makes the tranny work harder, but I have no idea what the temp was with the stock tires (didn’t have the gauge installed then). Also, where is your temp sensor located? Mine is on the output line from the tranny, just before it goes into the in radiator cooler (on the top). Is your temp sensor located before or after the tranny cooler?
 
I have the cooler placed AFTER the in radiator cooler, the filter adapter placed after the external cooler, the temp sender is part of the filter adapter, I was going to add another sender on the tranny output side just to check the difference, just have other projects to deal with at the moment.
 
Ok that makes a lot more sense now. I’m running a similar set up, just a different location for the temp sensor. Do you know if 2 WD or 4 WD makes a difference as far as tranny temps are concerned?
 
I have my gauge sensor about 6 inches from the trans fluid out port where its hotest. Also have a cooler plumbed after the radiator. On hot days and climibing steep hills for long periods of time it can get up to 250F. My normal cruising is <200F. Sometimes the TC will slip on the freeway and it shoots back up. Anything below 200 should be all good. Im running 35inch tires with 4.56 gears.

Maybe this will help.
TransLifeChartfromHECATInc.jpg
 
i also have the sender unit placed about 10" from the output on the tranny. i have no aftermarket cooler....yet. i wanted to put the gauge on first to see the benchmark then see how much the temps dropped when i installed the cooler.
 
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