I'd use it for sure at highway speeds. But what about city/town driving at speeds not exceeding 45 or 50, for example? Is it more fuel efficient to leave it off? Does it extend the life of the automatic transmission to leave it off or to keep it on?

Please tell me the pros and cons either way, and your recommendations. I'm driving a 4.2 V6, if that matters.

Thanks all.

 

The usual recommendation is... "if it hunts gears, downshift"

I usually leave my F250 in OD. If I am coming up on a big hill and am towing, I will usually let the tranny downshift when it is ready and then stick in 3rd until I am over the hill.

Just my opinion,

Jim Henderson

 

I agree with Jim. Generally leave it in OD. Mine shifts into OD above 35mph on level ground with a light load, saving a little gas.

I always take it out of OD on long downgrades because there is no compression braking in OD due to the coast clutch. That saves the brakes big time here in the mountains.

Jim

 

[updated:LAST EDITED ON 04-Dec-02 AT 03:56 PM (EST)]I drive my `99 Ranger, 3.0 V6, 4.10-rear, 4X4, (4R44E-Trans) much the same as the previous two posts mentioned - it's a compromise (like everything) between MPG vs. brake-wear & trans-wear - but I'd rather pay a little now (fuel) than alot, later (rather SOONER!) (Trans & brakes wearing out sooner, ESPECIALLY the Trans!). I do specifically leave it OUT of OD for short, stop & go driving (i.e.-heavy traffic, lots of signal-lights & stop signs) and I also drive alot of hills and mountains (and whenever I venture within about 10 miles of a major city!), BUT when I believe I'm going to be in excess of 40-45 mph for more than, say three to five miles, I'll go into OD (and hopefully get to STAY in OD !?!).

I seem to be getting very good service life out of my Trans. as well as my brakes - so far, at 66,000 + miles, and I do (have done) a good bit of heavy-loads, up and down mountains and around the farm (off-road, OVER-Loaded firewood hauls and hay).

Just my opinion.

Glenn . . .

BIG PS - SERVICE the Trans. ACCORDINGLY - 30,000 miles religiously, under "severe" or "Special" operating conditions I'd do it MORE OFTEN - 15-25,000, or once every year to two max. - And make CERTAIN the correct fluid is being used!

Best of luck . . .

 

I had a '92 F-150 once. It had the 300 I-6 with the 5-speed manual. I swear, if I used OD, the fuel economy was terrible. I drove in 4th gear all the time...I got 21 mpg on the interstate that way. My theory is that in OD the truck just had to lag and pull too hard. In 4th, it was a comfortable RPM for it to cruise.

My current truck is opposite. I tried turning OD off through a tank of gas, and I got 13.9 mpg. With OD on, I get about 16. So I always use OD with my 5-speed automatic unless I'm towing or pulling up a hill. Also, when those pesky PT cruisers and riceboys start showing off at red lights, I turn OD off temporarily too

 

I drive with the OD locked out under 40-45 mph. The particular type of driving I do is 50/50 hwy/city. I get around 14mpg with a 5.4 and 4R70W in a 5200lb 4x4. I downshift on particularly steep hills.

I've found that driving an automatic using manual methods really doesn't make it fail any faster. At 90k I started manually shifting a '91 Explorer with an auto. I decided to do this when I noticed the front pads were wearing really fast after changing them again for the 3rd time in 25k miles. It had well over 150K when it I got rid of it and the tranny was finally nearing it's end and the rear brake seals were failing. The '91 Explorers were known for bad trannys and premature failure. I also noticed when I manually shifted the automatics the brakes didn't wear out nearly as fast.

While brake pads are cheaper than a new tranny, I think I may have stumbled onto something. Just my particular experience, not saying it's the right way.

-Kerry