anybody care to comment about possible overcooling an automatic tranny? by putting too big of a cooler on it.

I always thought over cooling was possible, however my new GMC Yukon truck has the factory external trans cooler and the radiator cooler, and the factory trans temp guage.

in this weather, the trans temp never goes over 110*F

I always thought 160 was minimum operating temp for a tranny, but after watching the new truck, appearently by GM design, you can NOT over cool a tranny.

 

Here's a little chart for trans temps and miles before it goes out at those temps. http://www.txchange.com/heatchrt.htm

Here's a neat little page about lockup. http://www.leeric.lsu.edu/bgbb/7/ecep/auto/f/f.htm

It pretty much states most don't let the converter lock until at least engine 120* temp.

Here's a link to a previous post which temps down to 115 were talked about. https://www.thirdgen.org/techbb2/sho...hreadid=136749

 

What is the range of the stock guage?

 

owners manual says NORMAL operating temps for tranny are 100-265*F
higher than 265F a warning light comes on.