The 4L80 is built heavier than the than the 4L60 but they both had similar issues, mostly in the overdrive section. I had a 2000 K3500, crew cab, dually, diesel, only had 150,000 miles on it when I had to have the tranny rebuilt, it was the overdrive section. That truck had factory coolers for oil, power steering/hydroboost, and two for the tranny.
Last edited by 78buckshot; 02/27/2025 2:49 PM.
