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Transmission Oil Temperature

31K views 37 replies 16 participants last post by  SoK66 
#1 ·
JK Wrangler Rubicon,
At what temperature does the transmission hot oil light come on ??
 
#7 ·
I'd be curious to know... I have had my trans temp up in the 240's range and no light. Then again I was trying to push in reverse my big assed E3 trailer up my driveway.... and YES I have a trans cooler. Even had the fan on. There just is not enough oil flow in reverse to keep it cool. I have seen smoke coming off the thing before so it makes me wonder if the trans flash even works with my early '07.

BTW. 240 used to be the high end of "normal" in older transmissions and 260+ was "HOT". So I do not know what the JK temp sensor trip is at which all of us are curious about.
 
#8 ·
I don't know when the light goes on either, but...

The computer considers the transmission to be overheated above 240°F,
and super-overheated above 260°F.

jocrazy0,
Did you say you got the trans temp warning recall done on your "07?
 
#10 ·
As far as I can determine yes. I received the overheat recall notice and took it in IIRC, I have taken it in for every recall. I find three sheets for transmission work where a "flash" was performed but I cannot identify specifically which one was for the overheat. That was a long time back, again IIRC.
 
#12 ·
Oh goody! Yet *ANOTHER* transmission hot oil thread. This should be fun. (where's the eating-popcorn and watching the show emoticon to insert here?)

Oh and no, my hot oil indicator has never come on either, but it probably comes on when the temperature is a little too hot.
 
#13 · (Edited)
Okay I read 270 in a thread on wranglerforum. That seems high and could be totally wrong, the op was confused about what the hot oil recall actually did.

And what stock tech did you offer this tech thread? Actually this was a direct question followed by lots of off-topic answers and two or three on topic;)

No need for popcorn just yet.
 
#17 ·
It was not my intent to dredge up all the old transmission temperature issues on the JK.
I only wanted to know the temperature setting of the Trans Hot Oil Light.
I have an aux trans oil cooler installed. After a 35 mile highway run at an OAT of 108 degs, I measured my transmission pan temperature with a laser thermometer, and it read 204 degs F.
I've read on several transmission sites that trans oil temps in the 200+ deg range start to deteriorate the trans oil and ultimately the transmission.

Thats all...........
 
#20 ·
After a 35 mile highway run at an OAT of 108 degs, I measured my transmission pan temperature with a laser thermometer, and it read 204 degs F.
I've read on several transmission sites that trans oil temps in the 200+ deg range start to deteriorate the trans oil and ultimately the transmission.

Thats all...........
You're good. 204 is nothing to worry about at all.
 
#18 · (Edited)
Where in the world is your transmission cooler?? I have a temp gauge on mine, while driving normal (i.e. not towing) it runs only 30-35 degrees above ambient. So on summer Dallas days, at 105, the temp gauge while driving reads in the 140 range, and only in stop-n-go traffic does it climb into the upper 100's. Towing is a bit different. When pulling my heavy trailer, the gauge reads 50-60 degrees above ambient (driving) and sometimes gets into the low 200's in traffic. Only when backing up where there is low air flow and poor oil circulation does it get in the 220+ range.

So in my mind, with a properly installed oil cooler, it should never get into the 200 range when driving, and only into the 200's in extraordinary situation (go slow off road, towing, heavy traffic....maybe). Even offroad (Gilmer Texas), I do not recall the gauge getting up to 200 in 4lo climbing some of the go slow hills.

And my oil cooler is AFTER the in-radiator pre-heater/cooler too. Some people bypass that one, but any heat you can dump before final cooling seems to me to be a good thing.
 
#19 ·
i dont remember if mine was done under recall or if the tech did it regardless. my build date is 01-23-07. the hot oil warning does in fact come on. i didnt have an aux gauge at that time.

it came on last September running the beaches at OBX in high range.

if you dont have one, an aux cooler is HIGHLY encouraged. it really takes the worry out of it.
 
#21 ·
Factory service manual for 08 says the Mysterious DING warning(the hot oil light replaced it) was set to come on at 240, so I am assuming the hot oil light comes on at the same 240......It was never explained anywhere what the mysterious ding was, thats why they added the hot oil light.........I read Atf 4 trans fluid will boil at 255 or there abouts, been awhile since I read it.

Before I added my trans cooler my JK's trans ran in the 220's while wheeling moderate trails, and thats reading it with the Aeroforce gauge.
 
#25 ·
Despite Chrysler's well planned efforts to avoid responsibility, including having their call center rep try and stonewall discussions on JKO about this serious defect, by now it's well established the JK automatic needs additional cooling, particularly on the ULs. Just a matter of time before the NHTSA investigation into JK fires gets to the bottom of this and orders fitment of the FACTORY aux cooler being installed on JKs sold overseas. Chrysler's even been caught fitting them on warranty replacement trans jobs here in the USA. They know the problem, they know the fix, they just don't want to pay for it unless a gun is held to their little pointy corporate heads.
 
#27 ·
Whatever the hot oil warning setting is on the JK it is too high, one time warning and what is clinging to the tranny dipstick when I pull it out ain't a pretty sight and that @ 20K km
 
#28 ·
I ran mine for about 11k miles before I installed an aux cooler. I got the "ding" a couple times before it was installed. I flushed the fluid a couple weeks ago (7k miles later) and what came out looked pretty good, a little darker than the new stuff but no burnt smell. Has made a significant improvement in shift quality. Worth doing if you have any concerns the oil has gotten overheated.
 
#29 ·
I got the message on Sat climbing a long hill in 4 hi. Pulled over immediately and let it sit for 20 min. Finished the climb in 2 hi, and made it the 50 miles back to pavement in 2 hi with no more issues. However, the fluid is getting changed this week and a cooler is going on order.
 
#34 ·
Last year I came across a guy at the top of Imogene Pass near Telluride with his "Hot Oil" light on. He was in a bit of panic. Turns out He'd driven all the way to the top, 13,000 ft+ in 4-Hi. His first 4x4, didn't know anything about when to use 4-lo.
 
#36 ·
Just got back from Grand Canyon towing about 3,200lbs of pop up trailer with stock rims and street tires 255/65/17. A cooler and folding tables in the back along with 2 kids and the wife. 5.5 hours of 60-70 mph with o/d off and a B&M tranny cooler with a temp sensor in the return line to the pan. Much to my surprise the temp on the tranny never got above 150. Ambient temp was between 80-100 degree from Las Vegas to Grand Canyon Village on southrim. The only time it climbed to I think 160-170 was when I was stuck in holiday traffic in Boulder City right after Hoover Damn heading to Las Vegas. Got up to 65mph and temp dropped again to about 130-140. Get the cooler and take care of your tranny.
BTW, I think the best way to cool an automatic is to pull over, shift into park and let it idle. If you have a tow pkg on your jeep you have a piece of shit tranny cooler in the radiator. So idling the engine will keep circulating the tranny fluid through the cooler.
 
#37 ·
If you have a tow pkg on your jeep you have a piece of shit tranny cooler in the radiator. So idling the engine will keep circulating the tranny fluid through the cooler.
Yes, idling in park will help cool the transmission.
Tow package or not, the automatic JK comes with a transmission cooler, mounted in front of the radiator, not in it.

I'd like to see a comparison between the sump temperature and the return line temperature from the aux cooler.
 
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