I was doing 75 today with 1000 lbs in the bed. The ambient temp was 85, and my trans temp was 145. I am only concerned because I'm about to install an extra cooler and fan for when I'm towing the 11,000 lb load this summer in the 110 degree heat. I wonder if, when I'm not towing that load, that the trans fluid may get too cool, even with the aux fan off. Set me straight.....

 

It really can't get too cold. There's allot of friction in the trans, and the fluid runs through the rad. 145 is good. when your crusing with the load, you'll see 165 or so. That's not bad either. Start worrying at 190 - 200.

The extra trans cooler is definitely a good idea though. It wasn't until 03 they FINALLY added an air over water cooler

 

It gets up to 190 sometimes, without even a trailer being on it, so the cooler is going to be a good addition.

 

MMMM

That must be local driving. I rarely see that with my loads. But I have an 08

BTW, I was editing when you replied.

I was talking about running flats at highway speeds

 

That is running nice and cool.
When I lived in AZ on the hot days tranny temp would read as high as 165 sitting in the hot sun before I even started the truck.
Pix of gauges in Phoenix traffic in the summer.
https://www.dieseltruckresource.com/...l&ppuser=31624

 

In clear air, at 70 mph, on a hot day, 145* is perfectly normal..... as stated above. My DTT does not run much cooler than that.... maybe 10*.

As stated, keep it under 190* at all times and change the fluid & filter regularly and it should last you a looooong time.

11,000 lbs is nothing for you CTD, unless your in the Rockies! I would not bother with the cooler unless you start running into temp problems later on.
Just keep the OD locked out under 2000 rpm's and keep rpm's up at all times.... over 1800 rpm when towing!

IMO, a deep dish pan that holds an extra 4 qts ATF will do as much, to hold down temps, as a cooler/fan.

RJ

 

It also depends where your sensor is. Mine is in my hot line and sitting in traffic it'll get to 220 or so...I have a deep pan also.

 

Since I have 3:55's, I have trouble on really steep hills. On a particular grade, just outside of Hurricane Utah, I have to stay in 2nd gear, and the trans doesn't like it

 

Hot line here also. Only time I ever got close to 200* was Dallas gridlock.
I put it in Neutral and rev it to 1200 rpm.

I would shut down if I hit 220*. JMO.

RJ

 

I believe that's because your converter is not locked. I would put on a LU switch and see if you can lock it in second. I'm not sure if a stock VB will allow second gear lockup but I think it will. Otherwise an aftermarket one should.

 

Hmm, never heard of this mod, must investigate........

 

Clink HERE for information and installation instructions.
Easy mod and free, if you have some wire around the house.
Only cost would be a 2 position switch from Radio Shack - maybe $5.00 max.

It WILL work in second gear! Select your gear (2nd or 3rd w/ OD locked out) and throw the switch. The OP's 02 will always be locked up in OD, but some early 47RE's were not.
You can do a search on Mystery Switch..... or Lock Up switch for lots of user info.

RJ

 

Wow, thanks RJ! I will be doing that this week

 

Get the Lockup switch installed ok?
See any difference?

RJ

 

When my 2002 had a stock valve body in the trans. it would not lockup in 2nd, but it does now with the Goerend trans..