This may be a really stupid question but i've always owned manual trans vehicles up until now.
What does overdrive do and when should i use it?

 

not a stupid question most pepole havnt a clue what its for, overdrive is gear ment for highway driving basicaly 5th gear, makes the engine run at lower rpm's thus it works less, when not to use overdrive... in town under 50mph when hauling heavy loads in hilly conditions there are other instances...basicly wherever you wouldnt use your truck in 5th gear....dont use overdrive.

 

imnothot02 summed it up really good... od. is like .64:1 gear ratio and a 1:1 gear ratio means that the engine speed and the tranny speed are the same. the od means if the engine is turning 1500 rpm. the tranny output will turn 3400 rpm.. now those are just examples not exact figures of the .64:1 gear ratio. thus making the car go faster than the engine speed.

 

exactly right the idea behind it is to keep the rpms down at highway speed simply put lower rpm means higher fuel mileage...and longer engine life

 

Don't mean to split hairs but you can get to low of a engine speed that will do just the reverse it will hurt fuel mileage because the engine is lugging to much. thats why when you drive in town its beter to leave the od off.

 

I hope this isnt out of place because this is a Dakota forum, but in my 2001 Ram 1500, I carry probably about 350-500lbs of equipment in the back of my truck, plus a cap. Should I even be using o/d on the highway? And it would seem I should start using it all the time on surface roads..is that right?

 

running the od with just 3-500ls won't be a prob but do your best to not use it in town it's un necessary and as posted above can actually cause poor mileage my rule of thumb is od on highway only...lugging the engine isn't good for it...