This is to show my truck as I drive it, Please tell me if I sucked at OD.
Notice that at 40 secs it starts vibrating.

[youtube]Nk94qwd3cXE[/youtube]


let me know what can you find.

 

I really can't tell anything from that video, but what codes does your check engine light give?

 

22 and empty gas from Air conditioning. Just changed the IAC Valve Im suspectin the last owner didnt cheked the wire and itsnt getting enought volts.

 

If your ECT sensor (code 22) is bad, then your computer won't shift the transmission into overdrive at all!! The computer has to have a particular reading from that sensor before it lets the transmission make that shift.

To be honest, it never looked to me like your transmission shifted into OD in that video. You never got it fast enough. At 35-40 mph, 3rd gear and TC locked would put it at the rpms it was at in that video. You need to get it up to 60-70 before anything is noticably wrong.

As for the shaking, that entire video was shaky!

 

Didnt know about it, Ill look for a new mechanic to check it.

 

It very well could, you of all people should know that lower RPMs doesn't always equal more MPG...

My 4.0 explorer was geared very tall, by NOT using 5th, I GAINED nearly 2MPG, consistently... My truck is on the verge of being too tall geared with 31s, I ran a couple tanks not using 5th under 60, gas mileage was unchanged...

 

I understand what your saying and I agree. I never put my truck into 5th until I'm over 50 mph. But I'm still waiting for the day you learn that just because its true with your truck it automatically makes it true for everybody elses! The fact is the OP has a factory 2wd... stock size tires, stock gears. Driving on flat ground around 45 (speed mentioned in the first post), he won't get better gas milage in 3rd than 4th! Driving up a steep hill, sure, knock it down into 3rd, but driving on back country roads, overdrive will help.

 

I said "it very well may", not "it will", you're the one who said "it wont". The tires and gears were stock in my explorer as well... He won't know until he tries it.. Many, many people have reported getting better MPG on other forums by not using OD at all or under certain speeds. Another thing to remember is that his auto OD is taller than out 5 speed OD, further lowering his RPMs, and his 3.9 doesn't have as much torque to work with as our 5.2s either.

 

Hmm, you got me on the 3.9L comment. That engine probably does get better gas milage with higher rpms cause its having to work it's a$$ off in the low rpm range! I didn't even think about that before.

Lol, I don't believe your comment: "...many people have reported getting better MPG on other forums by not using OD at all..." If you're going 70, you need OD no matter what engine or gears or tires you have!

 

Disagree, specificlly around the RBV forums, with the smaller engines, especially the 3.0 since it's a high RPM rev machine, many people get better MPG not using 5th, it makes peak torque at 3600RPMs and likes to be run around 3k on the freeway, many times with oversized tires/stock gears, there simply ins't any torque with small engines to keep them moving in OD, the 2.9 in my B2 was like this when I had 31s and stock 3.45s, 5th was unusable at any speed, until I gave it 4.10s (and gained MPG). I also picked up MPG when I put in my 4.0 since it has so much more torque to move it around with.. One guy with a totally stock 2.5 ranger, switched out the stock 3.73s with 4.56s and gained a couple MPG, highway included. My buddy's has 3.55s and 31s in his 4.0 XJ, for years he wouldn't listen to me about not using OD, finally last summer he stopped using OD, gained 2-3MPG. There's a lot of variables going on so one thing that works for X combination of engine/tranny/gears/tires may not work with with Y combination of engine/tranny/gears/tires. It's best just to try it for yourself.