Here's a topic near and dear to many I'm sure. I tow a small camper (about 1500lbs) with my 98 Expy 5.4 liter. I just bought the truck last spring and towed with the overdrive defeated while towing last year. With a load this small, is that really necessary? With the overdrive disabled I run at a higher than normal RPM on the interstate. If I recall correctly, about 3000 RPM at 70MPH. I run Mobil 1 5W-30, but wonder if the higher RPM is hard on the engine.

A friend of mine has a Sequoia (trader!!!), and has about a 2000lb trailer. He keeps the overdrive enabled (on the interstate anyway) because the majority of the time it stays in high gear anyway. Interesting point, but isn't it still hard on that gear? I've heard the high gear is not designed as robustly as lower gears, don't know if that's true or not.

Any and all opinions appreciated.

 

I'd leave the OD on while towing if on relatively flat terrain and the trans does not constantly shift in and out of third gear. This will have a lot to do with your rear gear ratio. 3000 rpm at 70 seems like a lot (I turn 2000 rpm at 85 in OD)but it won't hurt anything.

I've never heard anything about certain gears being less robust than others. Maybe someone else can confirm.

 

The strength of the gears comes into play with 5-speed trannys. The overdrive gear is much smaller than the others, so it increases the pressure on the bearings due to spinning faster, and just flat out fails. I have had this happen before.

The Overdrive on an automatic from what I am told won't lock the torque converter. I am not sure how much of this is true, but the theory is if the torque converter is not locked, then you are heating up the fluid, and heat kills automatic trannies.

The only reason I feel you shouldn't tow in OD is if you are constantly shifting in and out of OD. This shifting causes wear on the clutch plates, and also heats up the fluid, and again, heat kills automatic trannies. If you are towing and it's not shifting out of OD often, then leave it in OD. When you tow a heavy load, you can often get better mileage with OD off because the engine can keep up the pace easier.

 

Here is the answer!!!!
On flat land, with the overdrive off, sense the position of the throttle. Now switch to overdrive and note if you have to apply the same throttle or have to increase throttle pressure. If you have to apply more throttle, do not use overdrive because it will tend to overheat the trans. and any increase in temp. will reduce the life.

 

Well in my opinion.....depending on how many people your Expy can haul (up to nine on some with the front bench) you can that much or more than 1500 pounds inside with people and gear. So in my opinion what difference does it make if you have 1500lbs inside or behind it? Does the owners manual say anything about turning the OD off when hauling 9 200lb people? (at total of 1800lbs) I don't think so. Plus, if you have the tow package with a tranny cooler and oil cooler then I wouldn't even give it a second thought.

Just my two cents.

 

I probably should have mentioned I do have the towing package with tranny fluid cooler and I believe oil cooler also. Typically when I am pulling my 1500lb camper I will have about 400lb of passenger weight including myself, + probably another 250lb in gear.

Interesting thought on testing the need for more throttle when going into overdrive. That seems like a good thing to try.

One thing about keeping it out of overdrive is that even on interstates you have rolling hills....plenty of big time power if you stay out of OD.

 

Buzzard, What gear you running, 3.31 with 33" tires? I have 3.73 with the stock size (still) 255/70-16's and turning 2000 rpm will only get me going about 67 mph!

The 98 Expy 5.4L has a 4 speed auto with 4th being OD and an electronic "locking" torque converter. Jetjock has a great test and I agree with Buz as well. If you are on reasonably flat terrain @ highway speeds, no strong head wind let her run in OD. If you notice the trans "Hunting" back a forth in and out of OD, switch it off. I would be more concerned running the motor a 3000 rpm all day then having her loaf along at 2000 rpm in OD, especially in light of the bigger radiator, engine oil cooler and trans cooler that comes with the factory tow package.

Petrol

 

Petrol, you hit the nail on the head, 33's with a 3.31 ratio. I'm looking into a 4.10 setup, but have a hard time parting with the ~$1,200 for parts and labor...especially after spending $350 yesterday to have an AC hose replaced because it had a hole rubbed though it due to a poor design.

 

$1200 sure is hard to come by around here so I feel for you. I just blew my tax refund by ordering a new Dell computer, eh wait thats right I had to pay $600 in taxes *****. Wife ain't going to like that. . lol

On the bright side, the new gearing will do for your hole shot and throttle response what no other $1200 upgrade can Bummer about the A/C hose, guess I need to check the routing of mine. Did it rub against a belt/pulley or have to sharp a bend?

Petrol

 

Bummer about the A/C hose, guess I need to check
>the routing of mine. Did it rub against a belt/pulley or
>have to sharp a bend?

I've never seen so may AC hoses as are on my Expy. Anyway the AC hose, I think they called it a supply hose, that had a hole rubbed through it is the one that has a portion situated in the tight little area between the right side firewall and the big square box just behind the battery. The hose in question (at least on my vehicle) didn't have any padding or plastic protection along a small section. This small unprotected section rested on a sharp sheetmetal edge. Hence, over time, and due to normal motion and movement, the hose got worn out. A 25¢ piece of plastic wrap or insulation could have prevented the problem. All in all, the mechanic SEEMED more upset than I was (he's actually probably calling Ford right now telling them not to fix the design flaw so he can perform more of these repairs).

Everybody ought to check this out on their Expy. If the hose is resting on the sharp edge, a little piece of foam pipe insulation should do the trick.

 

If it has enough power for you and/or you don't have to downshift much, leave it in overdrive while towing. It's all driver and terrain dependent. I only tow a 3500 pound cargo trailer full of band equipment or a sport boat (2500#). I leave it in overdrive except for the steeper hills (both up and DOWN, save the brakes!) OR when I have to pass real slowpokes on country roads (Yes, with the towed load!).

weps