H2 External Transmission Cooler Mod
 

At the risk of sounding ignorant, does anyone have a step-by-step or a link to a "how to" convert to an external cooler? I keep hearing that this is a worth-while mod to perform on an H2. I am mechanically inclined, but am not too familiar with the plumbing under the hood of these trucks. I'd just hate to start cutting on anything and make a costly mistake without doing the proper research.

Thanks!

After sorting through some of the previous threads on this topic, I noticed some photos of the placement of the aftermarket external coolers. On my vehicle, there is a factory-looking external cooler in the same location, routed to the radiator. My H2 is a 2007. Were external coolers ever available from the factory or as a dealer fix? This unit looks factory.

H2's have both an internal within the radiator tank and external tranny cooler. Some simply bypass the radiator cooler and use the stock external cooler while most bypass the radiator and install a larger external cooler.


The internal cooler is prone to rusting then leaking which destroys the tranny. This is a mod I'll tackle once I finish replacing my steering components and finish rust removal.

Cool! Thanks! Are you going to go with the oversize external cooler or just the bypass? What is the best way to do this? Do I need to cut any lines, and how difficult is the mod?

This one is a basic how to:


https://www.hummerforums.com/forum/h...-cooler-35751/


I will probably do the same setup eventually. I've had that cooler in my amazon cart for at least 3 years lol.

So, which line is the inlet and the outlet to the cooler, or does it really matter?

I'm thinking I would really like to do this mod. However, I've noticed that this transmission cooler setup seems standard for many GM vehicles. My '14 Suburban has the same setup. Anyone know if this has this been an issue in vehicles besides the Hummer?

Bottom is the inlet I believe.


I'm not sure if other vehicles have the same problem. I just know there have been a lot of H2 owners who had their trannys trashed from the internal cooler rusting and mixing coolant with ATF.