I posted a couple weeks ago about "leaking red stuff" was in fact tranny fluid my stand alone cooler had a massive leak so I ditched that and routed the lines through the stock cooler mounted in the rad you'd think I'd be all set right? no such luck! went to go snow plow first couple pushes trans. temp light comes on WTF so I went to napa got a new aux cooler ran it in series with the stock cooler plowed all day yesterday no proab. All better! anyone else have this proab?

 

Was the stock cooler unhooked for a while? Sounds like it was plugged up or you hooked the lines up backwards on it.
The transmission getting hot enough to turn the light on may have cooked the fluid. A fluid and filter change would probably be a good idea.

 

the rad is brand new & so is the trans also the fluid looked/smelled ok

 

By the time the Trans Temp light comes on the fluid's got hot enough to form varnish and change the chemical composition of the ATF. Maybe not a lot, but it's happened. Were it mine, I'd do a (fluid, not solvent) flush/refill ASAP just because the ATF is a lot cheaper than the transmission.

 

very true!!!

 

I have thinking about a Trans cooler myself since our dodges seem to have trans problems any way. I also push snow with my truck a Fisher 7'6 HD Plow. Do you think it would be a good move to install one on my 99 1500. I'm also running 35's as well

 

Yes. Definitely. Go for it. Most assuredly. Indubitably. Affirmative.

Plowing heats the trans rather nicely. I think it would be a good insurance policy for you. Get one of the thermostatic flow controls for it, and you will be all good.

 

And add a remote filter to it, too, while you hacking on the system anyway.

 

HeyYou, Thermostatic Flow Controls ? You lost me with this one. Old school man like myself don't understand big words like that.......LOL

 

Something like this. Below a certain temp, it bypasses the cooler.