RayCharles

I live in a place that has a lot of hills.
I've been towing a 4500 lbs boat trailer with my 2008 GX470. What mode should i be in? We normally drive in 4D but the next step down is 4. Should i be using that lower gear?

Thanks in advance,

Ray

Koz

Use the highest gear where the trans is not constantly downshifting. As you are towing and the road conditions change you can adjust which gear will provide smooth non-downshifting operation.

Koz

JohnJerk

I would refer to the owners manual (I have been meaning to check this myself for a long time). Typically leaving the vehicle in drive (4D) when towing will generate enough heat to be a problem to the fluid and trans and that is corrected by keeping the vehicle in 4 (eliminating excursions into overdrive). 4500 pounds is a significant load. I tow light loads (<1500 lbs) and switch between 4 and 4D depending on conditions. The manual should be clear on this - hopefully one of us can find the time to check it out.

HaveBlue

Driving in overdrive with a heavy load will unlock the torque converter and cook the tranny oil after a while. After that you will start to cook the seals.

cssnms

DO NOT tow in "D." Tow in 4th for the reasons stated above, the planetary gear is not designed for towing. Not to mention this is what Toyota says. Good luck and give yourself plenty of room.