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.

I am pulling a heavier trailer now, but some of this info might be helpful here.

I always thought my 1st downshift from OD (4th) was back to 3rd.......NOT!!! After buying a ScanGauge II and setting it up to monitor gear ratio and torque converter slippage, my 1st "downshift" is actually my torque converter unlocking. If I use the button to lock out OD, then both the tranny goes to 3rd, and the torque converter unlocks, but if the engine is not under a heavy load, then the torque converter locks right back up. Pulling my full sized trailer on the interstate, and manually shifting the OD off and on as needed in the hill country around here, the tranny temp. stays in the 155 to 170 degree range. The pull up the winding mountain roads around here in 2nd gear, torque converter unlocked will send the tranny tempurature to 200 degress on a hot day. The problem there is that I have to slow down for the curves, so the speed has to stay down...hence 2nd gear and torque converter slipping. On more straight line Interstate over the mountains where I can keep my momentum, then 3rd gear with the torque converter locked is the norm......keeping up with traffic is no problem.

I do intend to replace the tranny fluid every 30,000 miles or so.

[Bill]

As a couple posts have mentioned, this thread really shows how a gauge - an actual calibrated gauge - can save big bucks and big worry. I set mine up to monitor transmission temp, and at the same time, like MtnGuy, to show me what gear I am in. The 6-speed automatic transmission on my Explorer shifts so smoothly that I can't always tell what gear it is in, and I can almost never spot the subtle change that happens when the torque converter unlocks.

A Scan-Gauge ($170) or a AeroForce Interceptor ($250) is pretty cheap insurance if you have any concerns at all. They install simply by plugging a cable into a socket that is under the dash of all modern vehicles.

Bill