Over Drive

[bell]

I am on my third Trailmanor . I have used Dodge and Ford big vans asTV's. They both had V-8's.They both tow Trailmanors in fourth gear(overdrive) Just find. Do the 6 cylinders work in overdrive?

Good question. I tow at 65mph wth a Toyota 4Runner 6 cylinder and it does fine on level ground in 5th gear (overdrive?) Toyota recommends towing in 4th but this decreases mileage significantly. The tranny does do a lot of downshifting on hills or even slight rises in the highway.

Originally Posted by bell

I am on my third Trailmanor . I have used Dodge and Ford big vans asTV's. They both had V-8's.They both tow Trailmanors in fourth gear(overdrive) Just find. Do the 6 cylinders work in overdrive?

I wouldn't recommend towing anything in overdrive, even with the v8's.
I speak from personal experience after frying a tranny towing a 1200 lb boat while in OD.

Do you have a tranny temp gauge? tranny cooler?
What axle ratios are you running?
Are they "wagons" or "cargo vans"?
If you are towing in OD and your tranny temps are remaining normal, I'd be very interested in knowing what your setup is.

The TC of the v6 has got to be pretty marginal since even the v8's are only in the 6000 lb range (E150 with 5.4L v8) when properly equipped. If not properly equipped, some full size vans are not able to tow, period, depending on the engine/axle ratio.
Don't let the massive size of these vehicles fool you into thinking they can tow anything. I would first see what the TC of the v6 is, and then go from there.
Either way, I think you're pressing your luck towing in OD.

Unless you have a way of accurately measuring trans temp ( ie scan gauge or std analog gauge) ) I would suggest not using overdrive especially in 6cyl vehicles. The damage caused by overheating is not immediately obvious and is cumulative. Losing a few miles per gallon over several hundred miles is much less expensive than the cost of a trans rebuild.

[bell]

My Ford 350 passenger van , 3.73 RE ,has a transmission cooler.It will not down shift unless I am in the mountians.

[Wavery]

If you are towing down-hill or on flat ground and the trans is not "Searching" for lower gears, you may be OK using OD on most vehicles.

Once you get into rolling hills or even a head-wind that causes down shifting, get out of OD immediately until you are back on flat land. It has nothing to do with the engine size.

As was correctly mentioned previously.........gas is a lot cheaper than transmission work. It's even cheaper than the additional trans services that would be needed due to towing in OD.

Originally Posted by harveyrv

If you are towing down-hill or on flat ground and the trans is not "Searching" for lower gears, you may be OK using OD on most vehicles.

The boat I was towing was a 1/3 the rated tow capacity of the tv.
The tv was fully equipped with the factory towing package.
The trip was from New Orleans to Houston (as flat of a run as you can get).
The tranny went up in smoke because I too "thought" driving in OD was ok.

Engine size will certainly come into play in the means of much reduced torque for the v6.
Any time the TV will need additional torque (ie: overpass, hill, etc) and the smaller engine can't deliver, the tranny will compensate by downshifting.
On any equal run with equal loads, the smaller v6 engine will shift more than a v8.

Originally Posted by bell

My Ford 350 passenger van , 3.73 RE ,has a transmission cooler.It will not down shift unless I am in the mountians.

I wish you the best, as I too plan on running a Ford E350 eventually as my TV.
I had a E250 back when "250" really meant something and look forward to getting back to a full size van for towing.
I wish Ford would equip the wagons for towing as they do the cargo vans, but they don't, which currently limits v8 wagons to the 6000-7000 lb range.

I wish you had a tranny temp gauge, as I'd really like to know what your tranny temps are while running in OD. I'm very curious, but simply wouldn't risk towing in OD again, and wouldn't advise anyone to do so either.

Just for curiosity, you may want to check the condition of your tranny fluid. See if it shows any signs of turning brownish, or has a "burned" smell.

[Wavery]

Originally Posted by ED-n-KEL

The boat I was towing was a 1/3 the rated tow capacity of the tv.
The tv was fully equipped with the factory towing package.
The trip was from New Orleans to Houston (as flat of a run as you can get).
The tranny went up in smoke because I too "thought" driving in OD was ok.

Engine size will certainly come into play in the means of much reduced torque for the v6.
Any time the TV will need additional torque (ie: overpass, hill, etc) and the smaller engine can't deliver, the tranny will compensate by downshifting.
On any equal run with equal loads, the smaller v6 engine will shift more than a v8.

Down shifting from OD on a lock-up torque converter has nothing to do with the amount of HP or torque available. The vehicle will down-shift due to demand, not supply.

If you are climbing a hill the trans will down-shift (lock the converter) out of OD when the demand gets too much for the gearing of the vehicle. It doesn't matter if you have 150HP or 1500HP. It is a measure that is taken to keep from destroying the torque converter. It is not a measure that is taken to deliver more available HP to the rear wheels.

If you are talking about the transmission shifting to a lower gear, that has to do with throttle pressure due to a lack of available HP. That is a different thing and seldom has anything to do with OD unless it is a 5 or 6 speed trans with an actual OD gear.

The vehicle's Owner's Manual will state whether you can tow in OD or not.

Some vehicles should not use OD when towing at all. Although, it's only common sense that going down a long (not steep) grade can be done in OD, if the driver wants to save an ounce of gas.

Transmission failure is seldom due to a one time event, unless a major "Hard part" just happens to fail due to stress of that one time event. Most transmissions fail from an accumulative effect of abuse over a long period of time.

Your trans failure while towing your boat probabaly fell into one of the catagories.

I tow with F150 5.4 6-speed with 3.55 rear end. Both 5th and 6th are OD. There is no lock-out for OD, only a tow/haul switch for the trans computer. On level ground, it stays in 6th. On grades it will shift to 5th (2000rpm at 60mph). The trans temp needle stays in the normal zone. Engine does not constantly shift or labor. 2720. Seems to work great - computer indicates right above 17mpg at 60-62mph on interstate.