towing

[COUNTRY327]

Can I tow a 2000 pound camper in OD with out hurting the trans? If I install a transmission cooler will that help towing in OD?

[DCTUNDRA]

Nobody is going to tell you that you'll be just fine, because no one knows. First, if you're going to pull a trailer, then you should have an auxiallary cooler for the transmission. All automatics have a cooler already, it is generally co-located with the radiator. That tells you that automatic transmissions need oil coolers period. The cooler that is standard is probably sized with some margin of safety, for the gross vehicle weight and its attendant drag. When you start pulling a trailer, you used up some part of that margin. Who knows how much? If it is a light weight trailer, on flat terrain, on mild day, then you might still have some kind of margin. Same trailer, with an ambient temperature of 100 degrees, pulling a steep grade, and I'd almost guarantee that you've exceeded the capacity of the stock cooler. The only way you can really know what is going on is to install a transmission temperature gage. Almost all RV'ers of any size have these gages and know how to use them.

The second issue is unrelated to the first. The overdrive typically consists of a central sun gear and a set of planetary gears that travel around it. Most overdrives fail because of bearing failure in the planetary gears. Toyota reccommends towing with OD "off" for braking effectiveness. they don't address the strength or capacity of the OD unit itself. Perhaps there is a tranny expert on the forum that knows how robust the OD setup is for the Tundras and Tacomas. Ford has quite a history with this issue. They increased the number of planetary gears to reduce the individual loads, then beefed up the bearing separator/cage for the planetary gears twice before getting the problem solved. I think it took Ford about 10 model years before coming up with a robust OD unit.

All this being said, I have towed thousands of miles with my Tundra and have used OD when I felt the "drag" was minimal. On the other hand, when towing across the mountains of West Virginia, I almost never use OD. The engine runs just fine at around 3,200 rpm and it doesn't seem to hurt the gas mileage all that much. In fact I can't say there is a significant difference in mileage between towing in or out of overdrive.

[mdv]

I notice a steady 2mpg difference between using OD and not. Flat terrain, always OD on, as soon as TC unlocks, I kick it out of OD and let it lock back up. When things flatten out, OD back on. If in consistently hilly terrain or around town, OD always off.

[coal miner]

The Tundra is a work truck & rated to carry a load & tow up to 5000 pounds. It already has an oversize radiator & trans cooler & fan etc. So for a 2000 pound tow you don't need any extra cooler. The Tundra is made to tow this & a lot more. If your going to tow with a smaller vehicle or a car than you'd have to be careful not to overload that trans & a cooler may be necessary. Coal miner

[Saddlenow]

You should be fine. Check laws for having brakes on trailer, brake controller is next and adequate Weight Distribution hitch setup. Owner's manual on weights with gear and people. Tire pressures and weight distribution are critical with anti-sway if you find you need it with that light a load. Have fun.
Saddlenow