I recently took a trip that involved small mountains (CA coastal). I have always been told to turn the overdrive off when going up and down hills, but when I do this the engine sounds like it is straining. I was told to keep the tachometer always below 3,000 but I have to drive really slow to do this with the overdrive off, creating a backlog of traffic on the windy, two-lane roads. If I keep the overdrive on, the engine sounds happier and I can go faster, but I keep hearing my brother's warnings in the back of my mind which makes ME unhappy. How do I know when I should turn the overdrive off? Is there some magic formula? As you can probably guess, I am a female that knows nothing about vehicles.

btw, I have a 2000 Ranger 4X4 with 4.0l, 4.10, automatic.

Thank you!!!

 

As long as the tranny isn't hunting, leave it in OD. But if you're towing something, take it out of OD.

Me, I take it out of OD when climbing a hill, or in stop and go city traffic. But on the flats with no lights, it's on all the time. A don't think going over 3000 rpm is gonna hurt your truck, but 4500 or 5000 for sustained periods will.

 

It's the constant shifting between 4th and 5th that shortens tranny life. Ditto on the trailer on hills in OD and with a tranny constantly shifting. So with this in mind, just drop the OD when there seems to be excessive shifting. Climbing a hill in 4th at 3,000 RPM is not going to destroy your engine; hills eventually end and so do the 3,000 RPM's. BTW, keeping the tach below 3,000 promotes longer engine life, however sometimes normal driving requires that you exceed this. Don't panic. The occasional 3,000+ stint (like getting onto a freeway) isn't going to have that much impact on engine longevity.

 

i myself live in the 3000+ range. i've got bigger tires and a smaller engine plus mine acts as a brick-wall because of my lift. i've got 82000+mi. on it and i use penzoil 5w30 every 3000mi. and its still ticking just fine. keep good oil in her and she'll thank you! excessive shifts are a no no. o.d. i use only on open flat roads.

 

Going up, and especially down hills shouldn't hurt a thing if you keep it in OD. Like was said, you only have to turn it off for heavy towing. OD is strictly a highway speed "coasting" gear, and not meant for pulling. Imagine a 10 speed bike. Can you pedal uphill in 10th gear? Not without busting your hump. But then again, I'm sure the truck can AT LEAST pull it's own weight uphill in OD, especially if you have the 4.0.

Listen to your engine. If it's not shifting all the time trying to maintain a constant speed, you're fine.

Here's what happens if you TOW in OD, though: You get up to highway speed and the truck shifts into OD. The truck can't maintain speed because of the extra load, so it shifts back down to get up to speed, gets up to speed, shifts back into OD, loses speed, shifts back down,.... up, down, up, down, repeat...repeat... etc... Not good on the tranny and gears.


Also, always keeping it around 3,000 rpms or less all the time is BAD. You can build up deposits in your engine by not "opening her up" once in a while. Shoot, I put my truck to the floor at least once a week out on the highway and it winds out to about 5,000... Runs great!

Hope this helps!

 

this is true but for guys like myself with 33" tires and a 3.0 pulling them, its like towing all of the time so its no o.d. for me, well maybe just a little. i had a boat at one time that i pulled with this and jet-skiis i still have. poor truck. i know, i know, different gears.

 

I live & drive in the mountains & a little trick I use when dong so (& the engine seems to be lugging, before it down shifts), is to quickly lift off the acceleator pedal, then get back on it, this will cause the torque converter to unlock & down shift, so the engine can rev up & get back into it's torque & power band.

Once the hill is topped, it'll up shift on it's own.

As has been said, it's the constant shifting into & out of overdrive thats a no no. So if you're in a area in which this is happening, just turn the OD off with the switch on the end of the shifter, this will prevent the constant up & down shifing, which is hard on the OD clutch.

It will cause the engine"s rpm to rise some, but thats ok in the mountains & hills, as constantly lugging the engine isn't good either.

As has been suggested, if you're towing or hauling a heavy load in mountains or hills, switch the OD off.

The engine will rev higher, the gas mileage will drop some, but the computer won't allow you to over rev the engine & damage it.

In fact Ford has a daily, 3 mile, greater than 3600 rpm, "blow it out" suggestion, as part of it's "decarbon" maintenace TSB on the 4.0L pushrod engine!!!!

So don't be concerned about brief periods of higher rpm's, to get over a hill, let her rev a little, it'll keep it decarboned some, prevent lugging the engine & wearng out the OD clutch from constant shifting & you won't hold up traffic!!!! LOL

 

Do you happen to have a copy of that maintenance TSB for the 4.0L that you'd be willing to post?

 

Puppydukes, after rereading & thinking about your posted symptoms some, I also wonder if the tire size has been changed, such that the outside diameter is larger than specified???

If so, this can effectively change the final drive ratio, such that unless reprogrammed into the computer, can confuse the shift points to the computer!!!

So is the tire size as specified on the door jam sticker????

Rick there is a good read on the decarbon proceedure in the "technical stickey" at the begining of the Ranger forum, the TSB & links to it are posted there. https://www.ford-trucks.com/forums/s...hreadid=100739

 

Thank you for all your replies. I do have the 4.0l and 4.10 combination. The tires 16" and are 155/70's I think. They used to be 145/75. They are from Big O. My speedometer still reads the same, I have tested it against the flashing police signs that spout out "your speed, speed limit".

I have heard about decarboning the engine and I try to floor it once a day when I get on the freeway, but it almost always shifts before or at 3000rpm.

Although the truck is a 2000, the engine is a new(reman) one with about 9000 miles on it now. The original engine blew up at 101,000mi due to rotted out head gaskets. Ford said that they knew about the bad gaskets on my year/model engine but that the truck was out of warranty, so sorry... $5000 later I am a bit paranoid about this engine I guess. Ford did say that this new engine comes with the "new improved" gaskets.

Thanks again for your help.