Overheating Transmission on 4x4 long climbs Aux Cooler?

[beautifulisblue]

Hey folks need advice on how effective adding a aux trans cooler will be to keeping my trans temps in check,

 

I bought my 2001 with 300k from my uncle in law.  He was the original owner and always serviced it at my father in law's shop.  I only using for hunting, camping and occasional trailer hauling trips. 

I'm a park ranger in Nevada and love backcountry hunting, climbing, mountain biking etc...  My favorite spot involves a 45+ minute climb in 4LO to get up a series of switchbacks from 5500' to 8000'.  The transmission, and eventually the motor gets hot.  Trans 225+ motor 210.  Juice will read the temp sensor I installed in the transmission on passenger side (I know it's not ideal) but also a factory reading that's often 5 degrees hotter, so I run the hotter reading on my gauges.

 

I pulled the radiator, trans cooler, evaporator when I first got it and cleaned it as it was gunked up and extended the blow by hose below the axle.  I've replaced the water pump, thermostat (190), and coolant.  I also just replaced the trans cooler with a mishimoto one.  On the highway in Vegas I run 156 degrees on the trans, maybe 165 up a hill.  The trans would also get hot in 100 degree Vegas just idling for a long time (waiting at the dump).  I also replaced the fan clutch twice, once with a cheapo, then with a better brand to be more confident.  

 

It hasn't been hot since the new trans cooler, but I'm thinking of adding a fan aux cooler.  I'm getting pack llamas this year and will be hauling a small stock trailer often on rough and slow roads, as well as a stock rack for really rough areas.  I'm a backpack hunter so need to get to the wilderness trailhead, then hike in and camp.  Looking forward to llamas hauling 80 pounds each for me and not packing elk out solo anymore!  

 

I've got a big front bumper I'd love the mount the trans cooler in the hole where a winch once was to keep the lines short, but can do the under the bed as well.  My question is, how much difference should I expect from the aux cooler going slow over a long period of time? I love this truck and since I only put 8k miles a year would love to run it for a long time.

Edited April 17, 2020 by beautifulisblue

[Mopar1973Man]

Have the valve body modified for lock up in any gear. Problem solved. Temps will fall. The only reason it gets hot is climbing grades with torque converter unlocked.

[wil440]

1 hour ago, beautifulisblue said:

My favorite spot involves a 45+ minute climb in 4LO to get up a series of switchbacks from 5500' to 8000

Would you be able to do the same climb in 3rd low locked , if you are using 4th LOW then locking out the OD on that climb will mean it would be in 3rd and would tend to be more in Lockup 3rd than torque convertor 3rd.

Also consider doing the mystery switch which will keep the torque convertor locked once the pcm has locked it so it wouldn't come out of LU until you flick the switch back, this as said above with a standard valve body will only work in 3rd and 4th and NOT second, but if you are using 4th Low then I'd say you wouldn't need it locked in second.

I have just done a switch and what a difference that makes, I was having problems with our (UK) speed limits and the truck always wanting to be in convertor rather than LU at the respective limits, problem now sorted.

Take a look in the article section for @IBMobile LU switch, I didn't wire it quite like that and just used a switch and relay so I control when it comes out of LU.

My trans as far as I know is standard so while a modified VB would be nice AND LU in 2nd would be nice too I don't want to trash my trans just now, and I realise you could just mod 2nd gear but I'm going to hold off touching it until I can afford a real trans to go with it

Edited April 17, 2020 by wil440

[beautifulisblue]

48 minutes ago, Mopar1973Man said:

Have the valve body modified for lock up in any gear. Problem solved. Temps will fall. The only reason it gets hot is climbing grades with torque converter unlocked.

Not that I'm aware of, I know it got a rebuild with an upgraded TC.  I'm hesitant to do trans work because I'm sure that mine has at least 100k on it.  Hoping to do everything at one time.  Any idea on the general cost for valve body work?

7 minutes ago, wil440 said:

Would you be able to do the same climb in 3rd low locked , if you are using 4th LOW then locking out the OD on that climb will mean it would be in 3rd and would tend to be more in Lockup 3rd than torque convertor 3rd.

Also consider doing the mystery switch which will keep the torque convertor locked once the pcm has locked it so it wouldn't come out of LU until you flick the switch back, this as said above with a standard valve body will only work in 3rd and 4th and NOT second, but if you are using 4th Low then I'd say you wouldn't need it locked in second.

I have just done a switch and what a difference that makes, I was having problems with our (UK) speed limits and the truck always wanting to be in convertor rather than LU at the respective limits, problem now sorted.

Take a look in the article section for @IBMobile LU switch, I didn't wire it quite like that and just used a switch and relay so I control when it comes out of LU.

My trans as far as I know is standard so while a modified VB would be nice AND LU in 2nd would be nice too I don't want to trash my trans just now, and I realise you could just mod 2nd gear but I'm going to hold off touching it until I can afford a real trans to go with it

I'll look into the lockout, I'd just have to make the switch a missile type launch cover so my wife doesn't accidentally flip it.

[wil440]

27 minutes ago, beautifulisblue said:

I'd just have to make the switch a missile type launch cover so my wife doesn't accidentally flip it.

......

 try the grade or similar in 3rd, OD  turned off and see what happens, then decide if it would be better to hang onto LU a little longer with a switch

[beautifulisblue]

4 minutes ago, wil440 said:

......

 try the grade or similar in 3rd, OD  turned off and see what happens, then decide if it would be better to hang onto LU a little longer with a switch

I don't know if I've run it in third but I've definitely run it in 4lo with overdrive off.  I'm probably going under 5 mph the whole way up.  

[IBMobile]

 

4 hours ago, beautifulisblue said:

I'm probably going under 5 mph the whole way up.  

Your in 1st gear and never going to get lock up.  The trans doesn't shift to second until around 18mph.   Get a  Derale 15870 fan cooled heat exchanger; about $170-$180.

 https://www.bing.com/search?q=derale+15850+atomic-cool+remote+cooler&form=ANNTH1&refig=b420563ad6e04434a551403f0e3cd9a8&sp=8&qs=SC&pq=derale+15870&sk=AS1SC6&sc=8-12&cvid=b420563ad6e04434a551403f0e3cd9a8

[wil440]

46 minutes ago, IBMobile said:

 

Your in 1st gear and never going to get lock up.  The trans doesn't shift to second until around 18mph.   Get a  Derale 15870 fan cooled heat exchanger; about $170-$180.

 https://www.bing.com/search?q=derale+15850+atomic-cool+remote+cooler&form=ANNTH1&refig=b420563ad6e04434a551403f0e3cd9a8&sp=8&qs=SC&pq=derale+15870&sk=AS1SC6&sc=8-12&cvid=b420563ad6e04434a551403f0e3cd9a8

 in low range ?? surely not going to be in 1st is it ?

Edited April 17, 2020 by wil440

[01cummins4ever]

3 hours ago, IBMobile said:

 

  Get a  Derale 15870 fan cooled heat exchanger; about $170-$180.

 https://www.bing.com/search?q=derale+15850+atomic-cool+remote+cooler&form=ANNTH1&refig=b420563ad6e04434a551403f0e3cd9a8&sp=8&qs=SC&pq=derale+15870&sk=AS1SC6&sc=8-12&cvid=b420563ad6e04434a551403f0e3cd9a8

^^^^

This would be my suggestion, I have heard good reviews on these, I’m fixing to purchase one myself along with ATS  deep trans pan. I don’t believe the pan itself will help much on temps but getting it for the ability to have  

a temp probe in the pan along with a drain plug,, and this coupled with a thermostatic fan controlled cooler should do the trick