I have a 2003 Toyota 4Runner, V8.
Almost every auto/truck manual says that while towing, you should shift from Drive (5th) to 4th gear (or turn the overdrive button off).
My question is what is the "harm" in driving in the highest gear while towing?
I plan to tow a light trailer (1,000lbs) and the towing capacity of the 4Runner is around 5,000 lbs. Is driving in 5th gear going to put that much strain on my transmission and my V8?
Please Advise.
Eddie Fenton snipped-for-privacy@hotmail.com
If you are on dead flat land, using 5th is no problem while towing a light load. It's just that every time you start up even a small hill the transmission will be "hunting" back and forth between 5th and 4th gears, trying to find a good solution.
When you sense it kick down the first time, hit the button to leave it in 4th till the top of the hill.
And if you start down the other side of the hill and start picking up a bit of speed, hit the OD button again and keep your foot off the gas - you'll get a bit of engine braking which will save the brakes.
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The formula for horsepower is torque (ft-lbs.) x rpm x "a constant" (5252) = hp.
So, for the same horsepower to pull your rig in a steady condition, more rpm (lower gear) means less torque stressing the components in your transmission.
To add to Bruce's comment, very frequent shifting, or running in OD with the torque converter unlocked both create excess heat in the transmission. Excessive heat kills transmissions.
The 2000-2002 Tundra transmissions have been failing mainly in the overdrive gear cluster. Towing with those trucks in overdrive is asking for trouble.
Ken
Not sure what ken is trying to say here, weather it is okay, or not okay but, my take is this, the reason they say not to use OD is because the tranny will hunt for the proper gear when facing stiffer resistance (ie climbing hills, strong head winds ect.) the excessive shifting will pre - maturely wear the tranny.
but if the weight that you are pulling is light enough that the transmission does not jump around for a better gear then there really isn't any need to worry about keeping it in 4th, all your doing then is running the engine at higher rpm's and burning more gas.
if when you start on an incline and the engine is constantly jumping between
4th and 5th, your better off leaving the tranny in 4th constantly to prevent the excessive transmission wear.conversly you can controll all of this your self if you don't use cruise, when you feel that the engine is about to shift, let off the gas alittle and slow down. it will be easier on the engine too.
my 2cents
Dave
What about Tundra V8s newer than 2002, especially the new 2005 Tundra V8?
I'm planning on buying a 2005 Tundra V8 DC to tow a boat & trailer weighing
5,000 lbs. I will be making an 8-hour trip (each way) towing the boat over Interstates two or three times each summerWould it be best for the transmission for me to keep it out of OD the entirety of these long trips OR to just keep it out of OD on hills especially if it's hunting between gears?
Thanks, Sandy
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