I don't think it will change significantly. You can't expect coolant temps to stay exactly at 200 or 210, the important thing is that the system has the capacity to keep them under control when under load.
Gearing and engine temperature
- Thread starter B.E. Coyote
- Start date
I don't think it will change significantly. You can't expect coolant temps to stay exactly at 200 or 210, the important thing is that the system has the capacity to keep them under control when under load.
This is correct and why there is nothing to fix. If the engine is within its normal operating temperature range the temp gauge is pointing up.
I literally just replied this in Blaine's trans cooler thread...
I found out last year what improper gearing can do to trans temps even without a trans temp gauge...
2000 4.0L 32rh with stock Dana 30/35 3.07s on 33x10.50-15 Badak Xtremes factory rad/trans cooler setup at the time. While hurrying home (80ish mph) on a nearly pancake flat interstate after dark with 80* ambient temps, i noticed the engine coolant temp starting to climb over the 210 degree mark when it always sits slightly below it. I immediately realized by the rpm that the torque converter wasn't locking up due to throttle and load to maintain that speed. I slowed down and the engine temp came back down with the converter locked up. The super hot trans fluid going through the factory radiator/cooler was too much for the system to cool. I normally pay very close attention to my converter being locked up but was in a rush that night. If that can happen to me in the pancake flat Midwest, I can only imagine what it's doing to guys in mountainous states.
I found out last year what improper gearing can do to trans temps even without a trans temp gauge...
2000 4.0L 32rh with stock Dana 30/35 3.07s on 33x10.50-15 Badak Xtremes factory rad/trans cooler setup at the time. While hurrying home (80ish mph) on a nearly pancake flat interstate after dark with 80* ambient temps, i noticed the engine coolant temp starting to climb over the 210 degree mark when it always sits slightly below it. I immediately realized by the rpm that the torque converter wasn't locking up due to throttle and load to maintain that speed. I slowed down and the engine temp came back down with the converter locked up. The super hot trans fluid going through the factory radiator/cooler was too much for the system to cool. I normally pay very close attention to my converter being locked up but was in a rush that night. If that can happen to me in the pancake flat Midwest, I can only imagine what it's doing to guys in mountainous states.
My mustang does this in stop and go/bumper to bumper traffic. its an AOD so 1 and 2 are non-lockup and 3-4 are locked up in the trans. With A/C on and a lot of stop and go where the converter is working a bunch, I'll notice coolant temps creeping up until i turn off the a/c and/or get moving steady again. The trans cooler is in the tank right before the outlet back into the block, so its adding back temp to the coolant right before it goes back to the motor.
That experience made me regear my TJ but I just ordered new axles with 4.10s. I've contemplated adding a manual torque converter lockup switch on my TJ for interstate driving to keep the trans temps down but haven't dove into the wiring schematics to check it out yet. I installed one a couple decades ago on a ¼ mile street/drag nitrous car I had with an AOD trans and 3,600rpm stall converter. I did it so I could launch the car hard and hit the lockup switch near the top of first gear to cut down parasitic loss drastically. Bonus effect was on the interstate with the switch turned on, the trans temp gauge on that car showed it ran much cooler by eliminating converter slippage. On that car, the PCM had a signal wire for torque converter lockup that I ran through a switch to ground. Drove normally with the switch off and instant converter lockup when switched on.
That's why I'm on the fence about routing my TJ trans cooler. Most here run it inline after the radiator but I know now that even the tight stock torque converter still makes a ton of heat unlocked.
I was taught that you always ran a trans cooler before the radiator so that it wouldn't over cool the tranny. But that was also in the late 70s/early 80s, thinking and transmissions have changed since then.
After reading dozens of threads here over the years with differing opinions, I might be remembering it backwards. When the time comes, I'll go back to read them and do what Blaine recommends. The only local guy I trust to work on my Jeeps knows him personally from his California days and talks highly of him.
I'd do that as well. Blaine knows his shit. Communicating with the guy is a different issue, but once you pry the necessary knowledge out of him, its gold!
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