HI all
So I was able to put my custom van to the test.
2002 shortie with transplanted 360/46re and 3500 springs
I towed my RV which was about 6000lbs.
It was 100 degrees (probably the hottest day of the year) a few days ago when I had to tow it to a new park. At first for about 20 minutes it ran at about 215. When I go into stop and go it got hot...like between the 215 and 240 marks or right before the last white line. I turned on the heat - front and back which helped a little -Then OD turned itself off - which I was glad for since I dont have an overdrive cancel button. So I was driving in "2" in the city and not going over 45. It ran about 225 like this.
Then, I know this was dumb, I tried OD on the interstate. I got up to almost 70MPH. I was having a good time, until it got really hot again and the check engine light started to flash and it was at 235. So I pulled over, and it stopped flashing. I started off in 2 again and then OD turned itself off - so I traveled at 50-55 in 3rd. It ran about 225 then too. I kept the heat on and it ran OK to my destination which was about another 50 miles. As soon as the sun went away it went back to 215...it was sooo hot this day...
I have the upgraded copper two row radiator, new coolant, silicone heater hoses (glad I had those), and a newer waterpump. Man - at 240 I though I as going to blow a head gasket.
I think I should put in a tranny cooler...
any other ideas? Also how can I make my own OD cancel switch?

 

You may have a fan clutch that's not doing it's job and is your fan shroud in place?

 

yes

and when I would sit in traffic, I had to rev the motor to 2000rpm and it would start to cool down more quickly doing that

still maybe the clutch???

 

Not many people think of turning the heat on to cool the engine. Saved me more than once. Just remember to turn the fan on high.

 

Don't tow in overdirve. That's just a bad idea, and with that weight, it will smoke your trans right quick.

I think the O/D off switch is just a monentary switch, that sends a signal to the pcm. I wouldn't think it would be too hard to install one.... and having it would be a good idea. A bigger trans cooler never hurts either.

 

a 3 row rad is the way to go

 

I had one of those...went through 2 of them - they are junk IMO

I have a two row now from More Information for CSF 3392 (rockauto.com)

it is great -- it was just so hot outside - 100 degrees!

I checked the fluid and it wasnt burnt - thank God...but I probably should change it...I havent changed the tranny fluid for 5+years...what ATF4 is recommended? I will try to find a synthetic

 

If you don't mind me asking, why are opinions so split on overdrive and towing? A lot of people say that only applies to really old vehicles. Granted I'm driving a 24 year old van so it ain't exactly a spring chicken and definitely doesn't have a tow mode.

 

Does it say anything in the owners manual about towing? In the trucks is states "do not tow in OD". Not having a OD off switch is odd. Towing in OD puts a severe load on the OD unit and heats up the fluid. You can break things so not a good idea.

 

As stated below, it's a heat thing. Heat kills your transmission, and towing in o/d puts a heavy load on it, thus, generating a LOT of heat. If the trans gets TOO hot, the PCM will automagically disable o/d, and the light in the dash comes on. The fact that you HAVE the light in the dash, indicates you should have an O/D off switch somewhere. Should be a button on the end of the shifter handle???