Yep, probably talked about all over the net - but I'm making my own thread for it. (probably is a thread here for it somewhere too)

'99 Tahoe 5.7 4l60E 4x4(has the stupid t-case with the option for "auto 4x4") and think it has 3.54 gears

think I'm somewhere around 4klbs rig&trailer. It tows well as it sits (well, a lot better than my old truck) Maybe towing 3 weekends a month, 200 - 300 miles round trip.

But what can I do to make sure the tranny stays happy.

Do a monster tranny cooler, synthetic fluid, trans temp gauge, Transgo HD-2 shift kit and a vette servo. The biggest thing is to keep it cool and keep it from shifting constantly. Towing in 3rd will help since you have 3.42 gears. (GM didn't offer 3.54 gears in 99)

http://www.4l60-e.com/

my truck has a 700r that youre also not supposed to tow with in OD. i added a big cooler,temp gauge,remote filter,and B&M deep pan.

my truck has 4.10 gears,and small tires so towing in 3rd with the 6.2 is not real practical. ive always towed in OD. the transmission doesnt hunt between 3rd and OD,but before adding the above stuff,it definately smelled funky after my first real tow with it.

now the trans barely gets above 150* while cruising in OD. it only really warms up in 1st and 2nd,where the convertor isnt locked. the fluid stays red,and no more funky smells.

the other thing ive read is to change the fluid often,so i plan to change it every other big tow or so,so it will hopefully live another year. ive got a ranger OD/sm465 to swap in,prolly next summer. :smokin:

maybe apples and oranges,since the 700 is not a 4l60,but the main point im trying to get across,is like everyone else has said,you want to keep it from getting hot.

I have a 98 2door 4wd tahoe with 3.73 gears. It had a huge factory cooler, so I added a TCI (or B&M) pan. No issues to date. I typically use it to flat tow my Jeep (~4K LBS)