View Full Version : Using overdrive when towing

03-12-2010, 01:01 AM
I am new to camping with a trailer. I have a Edge M18 which weighs around 4300 GVWR and I tow it with a 2006 Toyota Tundra that is rated for 7200 GVWR. My question is should I take overdrive off when towing my trailer? Or is it ok to use my overdrive. My concern is overheating my transmission.

Any thought?

03-12-2010, 10:34 AM
ChefAnton, I don't know much about the Toyotas but these tow haul modes can perform a bunch of different functions. Shift points can change, converter lock-up can change some even have a braking feature. They do help with transmission temperature. My feeling would be to use it while towing, the people that designed the transmission put it there for a reason. I use mine all the time. Just my 2cents, I am sure there are other opinions.

03-12-2010, 11:10 AM
Don't know about Toyotas but overdrive off is not be the same as Tow / Haul

03-12-2010, 11:14 AM
I tow a 10,000 lb trailer with an F250 and use Tow/Haul when the terrain dictates. However, when I'm on nice, smooth, level highways (I know - that's an oxymoron in most places) I take it out of tow/haul and let it choose the gear (normally overdrive) it needs. With Diesel at almost $3 a gallon, every extra mile per gallon helps.

03-12-2010, 11:24 AM
I pulled a small TT with a jeep grand cherokee for a while. I always left the overdrive on as I think the vehicle was always programmed/designed for towing within its weight limits, and it would know whether to use o/d or not. The only time I took it off was if I was about to go up a big hill, or if it the transmission was searching for the right gear. I think it would be more harmful to keep it off, and effectively rev the engine higher than it needed to be.

03-12-2010, 12:02 PM
T/H and drive it like ya stole it.

03-12-2010, 12:44 PM
I don't believe the Tundra transmission has T/H mode. It'e either on or off. I'd just do what your owners manual recommends.

03-12-2010, 01:46 PM
Using the overdrive button on Toyota pretty much just drops the engine rpms when you are cruising at a steady speed. Someone told me that it could overheat your transmission if you used it when towing, and I wanted to get a group opinion on if this was true.

03-12-2010, 03:11 PM
I have the Tundra, when I hook up the RV I push the tow button, mine has a temp. gauge for the trans. < It has never heated up.I have been going to try it without, to check mileage diference, but always forget.

03-12-2010, 05:25 PM
I know nothing about a Toyota, sorry. I do know how the GM Allison works. Even with the Tow/Haul engaged the trans will still go into O/D. The tow/ haul mode only makes the trans stay in the gears longer and help with down hill trans braking. You can lock out the O/D by holding the Tow/haul button on for 2 seconds. Then a circle "O" will appear on the instrument cluster to tell you that overdrive is locked out. I have forgot many times to engage the Tow/Haul and really didnt know the difference until the trans brake wasn't working. MY 2cts Bob

03-12-2010, 06:40 PM
I tow a NT21FBS with a ford van 4:10 gears and 4.6 V8. I always turn O.D. off. It turns about 2800 rpm at 62mph the max torque of the 4.6 is at 3500.rpm
and its not as hard on the motor and trany as is lugging down the motor and haveing the trany shifting in and out of OD and the converter locking and unlocking
all the time. You need to check the specs. on your truck ( gearing ,torque-range etc.) and maybe call your dealer ? if its not in the book.
If its shifting up & down all the time I would turn it off, Higher rpms won't hurt anything but gas mileage.
Happy camping ! My camper still has the cover on and I'm more than ready to GO CAMPING!!

03-12-2010, 06:47 PM
Gas engines are not like diesels, they have a higher RPM top torque at around 3000 RPM. The advantage and best fuel economy is at this RPM.
I had a 2.3L Ranger that I use to travel with and I always got my best millage With the overdive off. So I never used the over drive unless I was traveling at 70MPH empty.

The gas engines need this hyer RPM to be efficient under loads. While the diesels like to shine at about 2000RPM

03-13-2010, 04:54 AM
I agree with turning O/D off while towing. If your vehicle isn't equipped with the Tow/Haul mode you will be going in and out of overdrive when towing. This could cause damage to your transmission. Most newer transmissions still have at least 4 gears even with overdrive off, so it is not like the old ones that were strictly 3 speeds. My dodge with overdrive off pulls my 310QB fine with overdrive off. It hits about 2500 RPM's at 60-65 MPH, and doesn't shift back and forth from O/D. That's about as fast as I want to go pulling a TT. I got about 9-10 MPG last year towing from north Alabama to Destin, Florida, and it only took me about an hour longer than if I had not been pulling the trailer. Your manual or dealer should be able to give you the best advise though. Good Luck.

03-13-2010, 04:46 PM
I would check your owners manual. I just purchased an M22 in Feb and hauled it 3 hrs home with a Honda Ridgeline. Honda only recommends using D3/Overdrive off for engine braking downhill. With a V6 or V8 Tundra, I wouldn't be concerned. Check on a Tundra Owners forum---I did this with my Ridgeline-- www.ridgelineownersclub.com (http://www.ridgelineownersclub.com)