2 gen towing

I was wondering if anyone can answer, owner's manual says to only tow in 4 (with automatic) can the transmission not handle it? or does trans temp get to high? I typically tow small trailer under 1000lbs for short distances (less than 10 miles at a time) If I tow in overdrive and soon as more power is required (converter unlocks) I shift down as I also can watch trans temps. Then it dawned on me it is possible trans itself can't handle the extra load.

 

It is the extra added heat The Transmission does not like!!

Install a Transmission Cooler to be on the safe side

 

Ty I assumed it was the heat (thus the trans temp gauge)but wanted to see for sure the trans could handle load in OD

 

It is converter slip that heats the trans fluid it will not slip in lockup but depending on the load the converter is likely to unlock even more so in OD.

 

yes converter unlocking heats up fluid very rapidly, the factory has 2 temp sensors on this transmission one monitors fluid output of the converter fluid

 

My biggest concern was to make sure OD in transmission is able to handle the extra load, I'm experienced enough (rebuilding several auto trans over 30 years)

 

Why tow in OD? The tranny will be continually hunting, shifting in and out of 5th (OD) and your gas mileage won't be any better than if you just leave it in 4th. The continuous shifting creates heat, which is as hard on the tranny as overloading it. An automatic shifts because it needs more torque available for what you're trying to do at the time, so shifting out of OD is just the tranny's way of saying "drive me in a lower gear". I've tried it both ways, and leaving it in 4th is less aggravating because the drive is smoother without the constant shifting. Sure, you're going to run about 500-1000 rpm higher at a given speed, but.....

I pulled a 5x8 cargo trailer (about 1600 pounds) 1800 miles in 4th gear and never had any issues. I started out trying it in OD, but it drove me crazy after less than 50 miles. My flatbed, with a tractor on it, I wouldn't bother putting in OD, because it would never get to 5th, much less stay there. At 70 in 4th, you're turning just under 3000 rpm, and at 55 you're only at 2250 or so.

 

The manual does state to not tow in OD, but at the same time under 1000 pounds for only 10 miles? I wouldn't sweat it too much. I tow with my tacoma regularly, and keep it out of OD unless I'm on a flat long highway for a while and then let it go into OD for mileage. The truck doesn't have issues with searching when on a flat. With under 1000 pounds he doesn't even exceed the payload capacity of the truck. If you're doing the same route with that small trailer regularly I'd suggest seeing what works and what doesn't. I don't like having my truck wound up all the time.

 

With a 1000 lb trailer you'll probably be fine. As a default I always use 4th gear and lock out OD when I start towing. But as conditions change will run in OD, especially with lighter loads on level terrain. Just because it is an automatic doesn't mean you can't shift it into the best gears manually. Read road conditions and downshift BEFORE the engine starts to struggle in OD. In mountainous terrain I'm shifting my automatic almost as much as I would if I had a manual. Especially on downhill sections.

If you're in OD and the engine is struggling you'll overheat both the engine and transmission. And it is better to just leave it in 4th gear than to have it shifting back and forth between 4th and OD. If you're able to maintain 55-65 mph in OD without the engine straining or the transmission downshifting then it won't hurt anything. But if in doubt, err on the side of caution and don't use OD.

 

1. it uses 2.9 gallons of fuel hour roughly in OD and 3.9 roughly in fourth, so it uses a noticeable difference in fuel
2. I have flatbed so very little wind resistance
3. it doesn't "hunt" in the terrain around here
4. I am currently fighting an annoying exhaust leak as I don't drive everyday the extra RPM noise is very annoying
5. it operates roughly 900 RPM more
6. the RPM you list depends on gear ratio installed 3.73 or 4.10 is the factory offering, aftermarket is another story, plus tire diameter changes RPM on corrected speedometer

 

I missed the part about the OP towing 10 miles or less. Stick it in D and go for it. 1000 pounds behind the truck won't even be noticed.