I have an 01 with 164K. just put in a rebuilt alli with the shift kit upgrade. Putting in synthetic with a deep pan. My question is should I start locking out OD when I drag my trailers? Don't want to do tranny again. My modes are a chip which I run at 60HP when towing, 4 inch exhaust, and a foam air cleaner. Already did the lock out upgrade from Kennedy Diesel. Would like all the pros and cons on this. Thanks GT

I tow all the time in 5th...even before the trans and had no issues, the alli is built to tow in 5th per Mike L.