Towing in OD won't hurt the 4l80. It's made for it. It even has a lower OD ratio than the 60e. What is hard on them is slow shifts in second gear for creature comfort, and pulling a long grade with torque converter unlocked, both can be solved with programming.Thanks. It’s a bone stock ’96 with 4.10 gearing and a 4L80e. I tow my 5500 - 6000 lb camping trailer with it in 3rd gear, on the advice of the transmission guy that recently rebuilt it.
I’m resisting the urge to mod the engine, though. The plan is to keep it stock.
What size tires you run?
Mine did just fine cruising over 70 in od with the 265 tires grossing around 17k with 3.73 gears.
Unless you have huge tires, or constantly pull grades, I can't imagine you NEED to stay in 3rd.