On the LLY, GM tried to improve emissions by raising EGT's (exhaust gas temperatures)the cheapest way they could. That was to reduce intake/turbo inlet diameters from 3 inches to 2.5. This raised EGT"S and reduced emissions but under significant loads these caused overheating of the engine and transmission. They also ran the diesel fuel through the engine to help cooling and added a fuel cooler into the system to try and control overheating. Every rig combination and their trip locations are going to have different problems and raise issues. When I was in California, I really got a kick out of passing Ford's and Dodges on the hills at 55 mph. It was when I went through Utah on the way to Illinois that the problems occurred, many continuous steep grades in the Rockies. As I said in my previous post, I added the AFE turbo inlet manifold and larger Banks inlet tube. I think it added 25 horsepower! The Earl's trans oil cooler was easy to install if you are a fair mechanic. Fabricating mounting brackets from aluminum stock is the hardest part, but was fairly easy. Any automatic trans used in towing can benefit by a larger cooler. The weakest link in your rig is the five speed auto, but its an Allison. Treat it right and it will serve you. Happy trails!
