I didn't see this yesterday. Thanks for the advice. That's not a hard job since the cooler is already there. I'll have to check out the B&M coolers or one of the larger ones.
It has that button on the shift knob for towing. That's what your talking about, right?
I always used the tow haul mode, not really sure what it did other than make the trans shift later, it probably firms it up a little too.
As to the OD. When you're climbing a hill, especially if you're using the cruise control, it will drop out of OD, then back into OD, then out of it. THe shifts in and out of OD will spike the temp really quick, it brings the transmission death. Whenver I was headed up a big hill I just grabbed the shift lever and put it in "3".
You'll rev the hell out of the motor, but the trans temps will stay reasonable. It's my understanding that the 4.8/5.3 motors don't mind the RPMs. It was never an issue for me.
I would highly recommend a trans oil temp gauge. That's what kills the lighter duty transmissions in the half tons. Before I upgraded the cooler the trans temp would hit 220+, which is very bad. After I put on some ginourmous stacked plate jobby they hardly ever got above 200, and usually only for a short period of time, climbing a long hill. As soon as we'd crest the hill the temps would drop back down to 170 ish.
I think this is the one I used:
http://www.summitracing.com/parts/HDA-679/
the factory one I think is 11" wide, but it's short, maybe 6" tall? The square one can be made to fit on the factory mount pretty easily, but it's got double the surface area because of the height. THis was on an 03 1500. There was nothing that got in the way. I used AN fittings to whatever the GM fittings were, can't remember what adapter you'll need.
87 'towed with a 4.8l Chevy 1500, and didn't kill a bus load of nuns' manche