Hey its me the Mexican Dakota Driver, recently I sent my truck to trasmission service (fluid and filter change) The mechanic told me to push the button of OD when Im driving at 45 miles/h tops, to save gas and protect the transmission. But Ive noticed that when Im driving full loaded on the back (around 600 kilos on it) and I turn off the OD It still begins to shackle as I haven turned it off, I noticed that When driving on highway I cant get OD off. Practically Im stuck on OD. What should I do? Plus I noticed lower gas mileage.

 

I'm not sure I understand... turning the overdrive off will not in any way save gas! Sure it can help protect the transmission around that speed because it won't be constantly shifting in and out of overdrive (number 1 cause of the overdrive units failing), but I'd say your mechanic is 1 for 2 on that one!

Now what do you mean by shackle? I'm not familiar with that one.

I do have to ask though... are you sure you aren't getting overdrive confused with the torque converter locking in 3rd when you have it turned off? Are the rpms the engine is running at indicitive that the transmission really is in overdrive?

 

Yes turning off OD will not give you more MPG. Without OD your engine will be turning at a higher RPM. Higher RPM=Less MPG. Yes you will save the transmission. The rule usually is to turn off OD when towing heavy loads. If you want read the owners manual.

 

I ment by "shackle" some kind of hard vibration when I accelerate driving avobe 45 miles/h
yup Im going o take a video of how I drive my truck to show you.

 

Do you mean "Shake"? If you have a shake above 45 you got an another problem. Like a U-Joint or something else.

 

the only time you need to turn the od off is if the overdrive is clicking up and down a gear consistantly. i tow my 5000 pound boat with the overdrive on if the highway is flat and the od isnt clicking on and off, if the high way gets hilly, then i need to shut it off. your gas milage goes down turning it off at high speeds and your engine is pushing harder, maybe thats why your getting that shake, engine is reving higher

 

So ok, heres what I do when I turn the engine on.
Put the key, turn the truck on, push OD button->drive.
Actually I realized that I get a greater gas mileage when I didnt know about the Od button and didn pushd at all. Im a noob I know!!! :-(

 

You can do whatever you want. But in theory you will get worse Gas Mileage without the OD on higher speeds.

 

I agree with you Crazy4x4RT that dakotas get better gas mileage when the OD is on. Also I remember two years ago a transmission expert explained the OD button to me and said, if I turn it off I will lose 10% mpg.

... TheLobo if you're OD isn't working you should notice when you drive 65 mph that your rpms might be around 3,000 rpms.

I have the same problem

 

On my 93 Dakota with 4-speed auto and OD, I can run 60-62 mph at 1800 rpm with OD on and about 2200-2300 rpm at 70-75 mph. Watch your tach after you get into third gear...when it shifts up you'll see a big drop in rpms...even driving around town in traffic.