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Keeping tranny cool

C

cpefy3

NAXJA Forum User
Location
Virgin Islands
Hey guys,
I have installed a B&M tranny cooler and have clean fluid; and I am wondering if anyone has other ideas on ways to help keep my AW4 cool. With the hotter months up ahead, I am trying to do everything I can to keep the temperatures down. Thanks!!
 
Don't bring it up to 210 degrees with the radiator? How big of cooler did you install?
 
markw said:
Don't bring it up to 210 degrees with the radiator? How big of cooler did you install?
Click to expand...

Leave the radiator lines off. Plumb it from the tranny to the cooler, back to the tranny. NO lines to the radiator, you'll need to cut the lines, attach to My 2 Jeeps are plumbed that way and have been for years.

Other than heating up the tranny fluid in COLD (like -0) weather. the radiator loop still heats the fluid to 190 or 180. My tranny temps run about 125-160, winter to summer, warmer if I'm towing or slow and steep. Then they can run 180-200.




As you can see, higher temps are bad for your tranny, profile says your in the tropics. No sub zero there, right?!?
 
I gotta agree with Talyn, on the tranny life expectancy however heat is a killer. I have a high dollar $250.00+ Deraile double stack cooler left over from racing days with it's own 10" fan and I have trouble keeping it cool. The B&M trans gauge only shows colors and maybe three temps and mine runs in the red going to Big Bear and in summer months around town. My cooler is running thru the radiator and the cooler is attached to the hood where my Chrysler big turbo hood vent is. I plan on running it straight thru the cooler without the radiator and see what happens. If it doesn't improve I will move the whole set up to the grille.
 
Boss Cherokee said:
I gotta agree with Talyn, on the tranny life expectancy however heat is a killer.
Click to expand...
Yes, excessive heat can be a killer. However that chart does not show excessive heat. Not driving hard my transmission with a cooler runs 150-170*. Driving a little hard I have seen temps hit 194*. This was also when the engine coolant was 212* and the oil temp was 216*. I find it hard to believe that a stock transmission with only the stock cooler would see lower temps.

Also, looking at some other of the similar charts they show "Transmission fluid Life" as opposed to "Transmission life" The transmission fluid life is more plausible.
 
I gotta agree with Talyn, on the tranny life expectancy however heat is a killer. I have a high dollar $250.00+ Deraile double stack cooler left over from racing days with it's own 10" fan and I have trouble keeping it cool. The B&M trans gauge only shows colors and maybe three temps and mine runs in the red going to Big Bear and in summer months around town. My cooler is running thru the radiator and the cooler is attached to the hood where my Chrysler big turbo hood vent is. I plan on running it straight thru the cooler without the radiator and see what happens. If it doesn't improve I will move the whole set up to the grille.
 
Desert4x4 said:
Do you guys think the engine would run cooler if you bypass the radiator cooler and only use the external?
Click to expand...

My engine runs a touch cooler after my aux trans cooler install that is plumbed into the radiator and my trans stays plenty cool.
I replaced all lines and fittings with Jegs pushlock hose and A/N fittings with a spin on pendant filter and a B&M temp gauge.
 
Last edited:
OutkastBoss said:
My engine runs a touch cooler after my trans cooler install that is plumbed into the radiator and my trans stays plenty cool.
I replaced all lines and fittings with Jegs pushlock hose and A/N fittings with a spin on pendant filter and a B&M temp gauge.
Click to expand...

Nice glad to hear it. Do you think using the radiator cooler is beneficial at all.
 
Thanks for all the replys, sorry it has taken me so long to respond. I am starting to like the idea of running the tranny lines straight to the auxillary trans cooler; however the only reason I hesitate is that living in Chicago we commonly see temperatures in the negatives during our amazing winters (sarcasm intended). I do not have temperature readings, the only way I know my transmission is starting to heat up is after a while driving in a mix of traffic and heavy acceleration the OD solenoid starts failing to lock up (occasionally) , which it never does in the cooler months. I am just now contemplating trying to figure a way to attach the lines directly to the cooler for the summer and then switch them back to passing through the radiator in the winter months. Thanks again for the input :thumbup:
 
markw said:
Don't bring it up to 210 degrees with the radiator? How big of cooler did you install?
Click to expand...

Talyn said:
What are your current AW4 temps?
Click to expand...

ParadiseXJ said:
Leave the radiator lines off.

My tranny temps run about 125-160, winter to summer, warmer if I'm towing or slow and steep. Then they can run 180-200.
Click to expand...

Talyn said:
I find that chart to be a bunch of BS. Most of the AW4s live a long life and I doubt they are all running at 175*
Click to expand...

I did not make the chart, and it's not AW4 specific, but the hotter the worser, no question.

cpefy3 said:
I think more often than not, it is the other way around. The heat from the engine coolant heats up the transmission fluid.
Click to expand...

Like I said...
 
They taught me that 175 F. is operating temperature. It is likely 20 degrees plus or minus is factored into the oil performance and design parameters. 220 F. and the oil starts to break down.

You have to remember these are kind of average temperatures, there are spots in the tranny (or motor) that get a whole lot hotter. It is likely that if your oils 240 F., some places in the tranny (or motor) are turning steel past red to that blue color before it turns black, maybe softens and starts falling apart (hot spots).

Around 15 F: my shifts slow down. That moment where the clutches slip before they really engage gets longer. Shifts can also get way late. My guess is the ATF is too thick to flow right at lower temperatures. It heats up pretty quickly (fifteen minutes?), but those minutes before it heats up, almost has to be hard on the clutches and cause extra wear nd tear.
 
Desert4x4 said:
Do you guys think the engine would run cooler if you bypass the radiator cooler and only use the external?
Click to expand...

No I thought the trans would run cooler! I think my engine heat problem is stemming from the combination of both trying to be cooled by an already inefficiently sized radiator not to mention 36'' tires on 4.56 ratio!
 
My trans aw4 loses 2nd gear once warmed up and come to a stop it slips like its stuck In 3rd until I slide it down to 1st.. If the jeep gets ice cold it will shift perfect... My trans cooler is going thru the rad aswell I'm gonna run straight thru cooler see if there's any difference... Anybody seen this issue??
 
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