Hello from another newbie. My truck is a 1999, f350, 7.3, 4x4, auto trans, with 4.10 gears. I'm pulling a fifth wheel toyhauler at about 11,500 pounds. my question is, is it ok to tow with the overdrive on once at highway speed. Im at 2250 rpm at 70 mph with the overdrive on. With the overdrive off i'm at 3100 rpm. Any advice will be helpfull, Thank You.

 

From what I have read on this site, everyone is pretty much in agreement that it is ok except if you are pulling in the mountains....if the transmission keeps looking for gears, then take it out of OD. My toy hauler only weights in at about 7k and would expect to be in OD most of the time. Will find out the end of January.

 

Do you have gauges to watch your EGTs and xmission temp? At 11k I would be concerned about that. Then (with gauges) on the flat, at highway speeds, I would feel comfortable with OD. Otherwise I wouldn't do it.

 

Towing that kind of weight in OD is not recommended. I do it, but I monitor my tranny temp and don't let it downshift/upshift too much. Definitely need a trans temp gauge if you don't have one. Welcome to FTE!

Max

 

Thanks for the advice, I don't have any gauges, yet. The truck is new to me. I live if Florida (No hillls).

 

It kinda surprises me you have an auto tranny with 4.10, must be something special, usually the auto has 3.73. I would definitely try to run in OD when you can. You can judge for yourself, if it sounds like the truck is pulling to hard, shift it down out of OD, but running 3100rpm in 3rd is awfully high. These engines can lug pretty hard, if it's pretty flat where you are you should have no problem pulling in OD.

 

Well shucks, thats what auto transmissions are for. Assuming it is behaving as Ford designed it to, stick it in OD and let the transmission do the thinking. If it shifts down, and the road ahead looks like it will shift up and down some more, then lock it into 3rd and leave it till the road looks level enough again. If you see a steeper hill coming, kick it into 3rd before you get there, so there is time for the torque converter to lock up in 3rd before the hill. You can see the change in rpm when the torque converter locks and unlocks. Learn what that looks like. IN ANY GEAR, on the highway, don't pull hard uphill for more than half a minute or less with the TC unlocked. Thats when the exhaust gas temperature will get high and eventually the transmission temperature too after a few miles. Shift down to whatever gear it takes to lock it up.
In 3rd, keep the rpms well below 3000, like 2600 or so for any distance, if for no better reason than helping fuel mileage. Similarly, try to stay below 2000 rpm in OD. However, depending on your rig, there is a speed that is high enough so that the rig will go over most easy grades and overpasses in OD without shifting down. On my 02 with 3.73 differential pulling a 5th that is a little over 60 mph. Find yours and stay above it if you can. That 4.10 differential is clearly marginal for freeway driving, so you'll likely have to settle for less than 70 except in pretty flat country. Florida is mostly flat enough.

Happy towing.

Warren

 

I always tow in OD.

 

I would keep it in OD unless the tranny starts seeking or you are driving in town. I have a manual, but my parents have a 2000 F350 dually 4.10 auto and they tow a 12K fifth wheel. They tow in OD unless the tranny starts seeking and just turned 100K. No transmission problems and no sign of them so far. They have always followed this rule when towing with all their vehicles and haven't had a problem with transmissions breaking, so go for it. The mileage will be much better anyway. Remember, the peak torque on the 7.3 is pretty low so if you are on the highway in OD you are in the sweet spot of the engine.

 

My 5th wheel "toy" is about the same weight as you are pulling. I stay in OD when I can but monitor it via engine noise and tach (no temp gauge yet). I have a good sense about when I need to get out of OD and "lock" it in 3rd and will do it far enough in advance that it is a smooth shift (that way my wife doesn't wake up either). I know the owners manual for mine (2000 F250 7.3l PSD) says never tow in OD but after almost 20K I don't see any signs of wear and the ATF looks good.

 

Not recommended by who? The owner's manual doesn't say that.

 

The owners manual does not specify, you are correct in that. It does say that the maximum trailer weight is 10,000lbs for a 99 F350 4x4 with 4.10 gears. It also states to never pull a trailer faster than 55 mph. So since we are not following manufacturer's recommendations, my transmission mechanic has told me not to pull over the vehicles maximum trailer weight in OD without a trans temp gauge. Better safe than sorry, so it's not recommended by me I guess you could say. Just my personal opinion on the matter. My 97 has 191,000 miles on the original E4OD with no service, and I tow up to 14,000 lbs on occasion. Maybe just sheer luck, I dunno.

Max

 

Woops! My mistake! Went back and read the manual, must have it confused with another vehicle I had. My apologies, it doesn't say "never tow in overdrive".

 

I've always towed in OD unless in hilly coutry. Never had a problem. I think the E4OD gets a bad rap. Their are thousands out there working hard with no problems.

Frank

 

That's why they make manual transmissions.
You do the thinking and select the gear that fits the load and the road based on your gut..
Nothing like a solid box full of real gears with a stick for stirring..
6th gear (OD) in my '02 PSD pulls any hill in my area and every hill on the Pa. Northeast extension while towing my 9500 lb. camper without a whimper.
And, I don't need to worry about tranny temps or gizmo failure.