06Cummins

Would it help out at all with MPG to remove the front drive shaft on my truck? Right now i am doing 100% stop and go driving and my milage in suffering..showing 11.9 on the overhead and i drive it real easy. Any thoughts? Also, would accelerating too slowly in these trucks cause worse MPG in stop and go conditions. I try to have a real easy foot only hitting 1700 to 1800 rpm and doing so slowly. Would it be better get put my foot into it a bit more and let her shift around 2K and get there at a quicker pace?? Thanks, Jason

Herrin811

i roll into the throttle firmly up to about 2200 rpm...15mpg avg overall

Removing the front prop shaft wont help much...unless your driving around in constant 4wd for some reason?? The TX case is already disengaged...

You'll still have the weight of the front axle...Plus with our hubs the front diff is always turning...You could pull the axles...But why??

Jfaulkner

Driving habits and wind resistance has a greater effect on milage than gear drag, otherwise the 2wd guys on here would be walking all over everyone in MPG, and you don't hear much about that. Fixing a low tire would probably have the same improvement.

SOhappy

Tried that on my wife's 2000 Jeep Cherokee (the front end bears an erie resemblance to that of my Dodge's, only not as stout......same engineers?) didn't help one bit, still got a lousy 18 mpg combined.

rammtuff

Usually us 2wd guys will get 2 mpg better. That's 10%. That's alot.
You spend $2000.00 dollars for fuel each year: I spend $1800. I buy a nice Christmas present for myself with the 200 bucks I save. In reality I spend alot more than $2000 in fuel every year so my savings are multiplied.

Jfaulkner

well me personally I'm not concerned about fuel. I play too much to worry about it. It also helps when your part owner of a small trucking company that burns about 7500gal a month so my truck usage is minimal. I'm hard on fuel, tires and brakes. Pay to Play is the words I live by.

But removing the front driveshaft sounds like the infamous "tail gate down" thing that doesn't work either.

Ridiculous

interesting thing you brought that up.
i saw that on "myth busters" on the discovery channel and they did confirm that the tail gate down creates MORE drag than with it up. if ya'll want the explanation i'll give it to ya but if not i won't type it out then. but i found this interesting b/c i did drive around with it down most of the time until i saw that and it indeed did hurt my MPGs more than with it up. so pretty interesting stuff.

and all in all i don't believe either that removing the front driveshaft will NOT help a bit but i bet it won't hurt to try it. i mean if it works for your application then what the hay what the who ya know. but for example like me, it wouldn't work for my application b/c it's snowing here right now and i drive gravel roads everyday...now i'd hate to get stuck or something and not have that front drive shaft, but if your driving paved roads with no rough terrain then why not try it?

and besides "herrin821" makes a good point as well, but if your bored one day and feel like experimenting then hay man...more power to ya!

Dodgezilla

I've been thinking about doing this myself. I will wait till it's summer though. If I pull mine, you can bet it will be in the truck bed though just in case I need it....

djbikeman

Your truck sits in the garage because it snowed 14" last night. I drive to work in 4x4 and make $200 that day. Now we're even...

slorocco

I've been wondering about that. I'd be interested in the explanation

Ridiculous

ok good i was wondering if anyone would care.

well here it goes...
first with the tail gate up...when one drives around with the gate up there is a "bubble" of air directly behind the cab inside of the pickup box. this "bubble" just sits there and rotates around and around with the cab and tailgate holding it in place. with this bubble, the air coming over the cab if deflected off, up, and over the tailgate. making little to no drag. now most people don't know about this because you obviously can't see it, but myth busters did the visual of it with a scaled down pickup, minature wind tunnel, and oat meal. very interesting stuff. you could very clearly make out the "bubble".

now with the tail gate down...when one drives around with the tail gate down this "bubble" i talked about earlier breaks apart b/c there is nothing holding it in place, therefore, the wind coming up and over the cab is no longer deflected by the "bubble". all it does now is come up and over, enters the box, and SLAMS down on the tail gate, therefore, pushing down on the truck producing more drag, and creating less MPG.

so that is the jist of it, on Myth Busters, they did the wind tunnel experiment i spoke of earlier, and the also ran two IDENTICAL trucks with the SAME amount of fuel and if you're familiar with the show these guys are for real, they don't do it half ***, they go all the way. so anyway, they ran two identical trucks and everything was the same, the only thing that was different in each truck was the, you guessed it, TAIL GATES, one up and one down. and they both ran until one ran out of fuel and guess which one ran out first, again, the one with the tail gate down.

so for me i'm convinced.
TAIL GATE UP IS BETTER FOR Mile Per Gallon.

Nuttymopar

I know on my 1st gen. Removing the front driveshaft made it FEEL faster or quicker. It didn't give me any better MPG though. I would have the manual hubs unlocked and the axles didn't move so it shouldn't have made any difference, but it felt quicker off the line and down the road. I took it off every year while I owned it.

I'm thinking about doing the same with my 3rd gen. Do some quick time trials down the road and then remove and see if better or not.

slorocco

"Ridiculous" Thanks for the explanation, I watch that show on occasion I missed that episode.

As far as the driveshaft thing is concerned, on the later trucks with the front axleshafts and diff turning all the time, removing the front driveshaft is not likely to save much on mileage. Now if you could convert to hub that unlock you might gain a bit more. However, I do have an old land rover that was built without locking hubs. The installation of locking hubs did not have a significant enough impact on mileage to justify the cost of the parts.

PapaPerk

Hmm....intresting question. Will removing the front D/S save fuel. Yes. How much? Not for sure. Only a test will tell you.

For city driving you have a number of factors for mileage:
1. Rolling Resistance - This is a constant. However it can be changed by using higher pressures in tires or by going to a narrow tire. Also obviouly if payload is increase the rolling resistance will also increase. The opposite is also true.

2. Inertia - For stop and go driving this is a big one. Ya know the 'ol force = mass X accleration thing. The more the vehicle weighs the more force it takes. And the slower you pull out the less power it requires because your accerleration rate is low. Not only does inertia apply to straight line acceleration but also to angular accerleration...like rotating shafts and tires and stuff. So when you install those big 44" super swappers on your truck your engine has to work harder to spin them up too speed because they weigh more. This is the catergory for your driveshaft. By removing the shaft you are not having to spin the shaft, u-joints, and associated gearing in the transfer case. Plus there is bearing drag, etc. This is one reason 2WD get better mileage. Plus they are lighter in general and have less wind drag because of their overall height.

3. Grade - It goes with out saying that going up a hill...your going to burn more fuel. Nuff said.

4. Wind drag - Wind drag is a huge factor in hwy mileage. It increase dramatically as speed increases. At city speeds 35 mph and less...not a huge issue. Above that...it becomes a problem.

5. Weight - See 1 and 2.

6. Driving habits - Here's another big hitter. If you like to rev your truck and do burn outs at every light...the mileage is going to take a big hit. Easy on the throttle saves much fuel. This is primarly because of #2. Also excessive idling is bad. It is miles per gallon. So if you are burning gallons but not making any miles....your not going to get much miles per gallon!

So I would try the shaft disconnect. If nothing else it will be an intresting experiment. And its has to help....it sure won't make it worse!