Has anybody heard of using the tranny drain plug for a temp sensor? I have a 2000 Cherokee classic. I would install a inline gauge but since I have had no trans issues, and I don't want to create more potential leak points, I figured its not worth the trouble. I had the urge to do this since I'm headed to death valley next week and I've always been curious how hot the AW4 gets (plus temps are supposed to be around 123F in death valley). Just for the record I do have the "Heavy Duty" cooling package, I've flushed the radiator, replaced hoses, replaced trans fluid regularly, and got a new mechanical fan clutch. Plus I installed a manual computer override switch for the aux electrical fan and I installed a extended idle switch (which does seriously drop temps of engine coolant at idle). So I think the engine will be alright but I'm just curious about the transmission (obviously the pan is not the most excellent indicator of tranny fluid temps, but like I said I'm not too worried). Any links to a part? How well would a temp sensor "clamped" to a trans line work? I'm pretty handy with electronics and basic microcontroller programming so if I could just put a thermistor or thermocouple I could do that too.

 

Nope. I had a transmission shop install my autometer sending unit in the pan. The AW-4 runs hot. I saw 230 when I lived in S. Cal with the Jeep cooler. I replaced that cooler with a very Large cooler. My pan temp now runs about 80 degree over ambient temp, so I run about 170 max here in GA. Keep your speed moderate in Death Valley and you'll be OK.

 

You don't want to put it in the drain plug, it is likely to get hit and broken off. There is a plugged bung in front of cooler lines that is used for temperature sensor in Toyotas, just plug it there.

 

^This, while the drain plug hole would certainly "work" it is the lowest spot on the pan and very vulnerable (especially since the sender will stick out several inches). I'm not sure if "later" (since the OP lists as having an '00) AW4s still have the threaded bung for the sender or not. If it is there that is definitely the easiest route, otherwise your options are either having a bung installed on the side of the pan (or putting one in yourself if you can weld) where it isn't as vulnerable, or plumbing it into the cooler lines (what most people do).


Also be aware that temperature at the "hot" (outlet) cooler line will generally be 20-40 degrees hotter than the pan temp.

 

I believe 1999 was the last year of threaded temperature port.
If a sender is installed in the pan, be sure and check clearance first, there is little room inside the pan.
I have a sender in the hot-line, and an IR temp gun to shoot the pan for comparison.
I like knowing the highest temp of fluid, high heat is what breaks down ATF.

 

1997 was the last year for the temp port.


Starting in 1998 that port was eliminated (not bored and threaded).

 

Thank you, I should have reviewed the following post of yours first, regarding the port.

https://www.cherokeeforum.com/f2/gre...4/#post2851314

 

Dang, I thought about the clearance too but now that I think about it I don't want the plug holding the trans fluid in getting whacked off....that would suck. And yea the bung was a great thought though.

 

I was looking for info on stock auxiliary trans cooler (the small cooler in front of the A/C condenser) performance, but I had a hell of a time finding any info. So your jeep cooler was the little air to oil cooler right (as opposed to the oil to coolant cooler mounted in the radiator)? 230F sounds like its getting cooled by engine coolant though. Regardless, thanks for the reply and the advice, I'll have the gf with me so I'll definitely take it easy.

 

Thanks for the advice. Yeah I'm not a welder by any means so I guess I'll experiment with just temporarily using a hose clamp and a temperature sensor on the hot line. The response to change in fluid temps wont be great and it will read a lot cooler than the fluid actually is but might give me an idea. Plus I'd rather mess around without cutting into stuff first.

 

0

 

You could drill and tap the bung. The transmission housing is aluminum so it will be easy to work. Just put a lot of grease on the tooling so it will pickup and hold the shavings.

 

Would you actually risk getting drillings in your transmission by doing that.


I wouldn't.

 

There's not a thing wrong with that approach, Ken!

...... as long as the trans is completely disassembled and sitting on your workbench. That way you can clean out all the drillings that aren't caught by the grease (of which there will be plenty), which would otherwise wreck your transmission in very short order.


And that's the ONLY way anyone should drill that hole.


Oh, wait. There is another way you could do it. Follow ehall's method, and make sure to film it and post it on Youtube so the world can laugh with/at you. You can title it, "Redneck transmission work goes wrong."

 

Lol ok i think he had a good idea though.....if i did that i would definitely remove the pan however. I would NEVER chance drill shavings going into the trans even with the magnets and filter.