Towing in 3rd vs 4th

[SnowDrifter]

My head is spinning trying to remember everything. Are the 4l60es fussy about towing in 4th? 3rd?

 

[iamdub]

Depends on the weight you're towing. Mine does perfectly fine in OD towing an empty-but-heavy-for-it's-size 14'x6.5' tandem axle. Throw my 800-1,000 lb. zero-turn mower on it and I feel it's just enough to need to stay out of OD.

You should use "Tow/Haul" mode regardless. I don't know how to tell how much stress the trans is under other than by watching the temperature, if your cluster even displays this. As for the engine, if it's not enough weight to know for sure if it's under more load than it could be, a little test would be to tow in 3rd and, while holding the pedal steady at the speed you want to cruise, shift it to OD. If you lose speed, then the engine is now lugging and you should tow in 3rd.

 

[SnowDrifter]

Depends on the weight you're towing. Mine does perfectly fine in OD towing an empty-but-heavy-for-it's-size 14'x6.5' tandem axle. Throw my 800-1,000 lb. zero-turn mower on it and I feel it's just enough to need to stay out of OD.

You should use "Tow/Haul" mode regardless. I don't know how to tell how much stress the trans is under other than by watching the temperature, if your cluster even displays this. As for the engine, if it's not enough weight to know for sure if it's under more load than it could be, a little test would be to tow in 3rd and, while holding the pedal steady at the speed you want to cruise, shift it to OD. If you lose speed, then the engine is now lugging and you should tow in 3rd.

~3250. Not heavy, but bulky. One of those 6x12 uhaul trailers. i.e. a brick

I have an upgraded cooler, e-fan manual override, and digital trans temp gauge. Temps can/will be monitors and kept in check. I'm not anticipating anything over 140. Could loosely determine trans torque load w/ manifold pressure.


I wish I was more familiar than I am with this trans tbh. I know some of the 90s chrysler units would blow right up if you tried to tow in OD. Not sure the cause of failure, but something in them just didn't work with the added load. Wasn't sure if the 4l60 is the same way or if it has any particular mechanical limitations, or if it's just a matter of keeping temps in check

 

[Erickk120]

I would only tow in o/d if the terrain is flat, or if you maintain constant lock up, if there are hills and or if you are constantly in and out of lock up I would just use 3rd to avoid unnecessary heat build up. This would apply for heavy loads for light/moderate loads the truck would probably not even feel it.