There were two reasons why I put in a separate tranny cooler: 1) with the stock radiator some people had the coolant mix with the tranny fluid and ruin their transmission (this happens on other vehicles too like Cadillacs), 2) I had to change the radiator and will probably have to change it again in another 40-50K miles and this mod makes it easier.

On the opposite side, the tranny fluid heats up slower and may not reach as high of a temperature as with the stock system. For me it takes a little longer for the torque converter to lock up when its really cold out. My tranny fluid probably will not reach 170-180 F during my normal drive.

 

[QUOTE][My tranny fluid probably will not reach 170-180 F during my normal drive/QUOTE]

now we need to find out how this affects tranny life!!
what is the design temp of auto trans??
one benefit may cancel another?

 

We just bought our H3. Is there a way to tell if the radiator has been replaced?

 

One of the problems with top plastic tank on the original design was that it could contact the top center of the rad support. The design of the new radiator has the upper tank shifted to the rear more to create clearance to the rear edge of the rad support.

You might have to search for pictures showing the original design and the slice worn into the top tank.

Perhaps someone can explain this more clearly for you than me.

 

Thanks CHP. After reading the trans temps with the stock setup on link you provided I just ordered the Hayden 405. It gets real hot here and heat will kill a tranny. We also tow short distances. Not to mention if the radiator fails and I get anti freeze in the tranny.

 

When I get past the "magic" 50K mark, I will be installing either the B&M or the Flex-a-lite below and bypassing the OEM radiator all together. I am going with a cooler/fan combo due to the lack of air flow when wheeling plus the BA bumper/Winch upfront blocks even more air flow and the mounting locations are endless.

B&M Hi-Tek Automatic Transmission Cooling System 13-1/2"x9"x3-1/2" with 9-1/2" diameter fan:
Hi-Tek Automatic Transmission Cooling System 13-1/2″x9″x3-1/2″ with 9-1/2″ diameter fan | B&M Racing & Performance Products

Flex-a-Lite #45951 Shrouded HD Remote Oil Cooler:
Remote Mount Cooler/Fans

 

Thise look nice for whelling. We mostly run down the highway so I think that other will be ok for me.