BrunswickYota

Ok....please keep the yellin to a mininum.....lol
I am thinking...that if I take off the front drive shaft, I will gain more milage..maybe small or not noticable...but anything to help anything in this day and age.
My question is if I do this...will I inadvertantly mess anything up? I know I live in south GA, but I just don't get into 4x4ing...reason I am on this site is cause of all the knowledge...
Any feedback?

98sr5tacoma

take the rear one out while your at it. but no dont remove it it wont affect anything. you can put manual hubs on and get better mileage. and even if you did you would only gain maybe a dollar or 2 per tank barely worth your time

BrunswickYota

Ya...just a pipe dream I know...but thanks...just a hairbrained idea...lol

MudHippy

Wouldn't hurt nothin'. It don't weigh enough to matter though, I don't think.

Jerk that and the rest of the front axle off, then we're talking a noticeable weight loss. If you never use it, why should it be there?

notanymore

if you pulled your whole front diff out that might help your mileage a bit, its kinda heavy, but the drive shaft doesnt weigh enough to really do anything

881stGenRunner

he is saying he is going to pull the front shaft so the entire front end doesnt constantly spin (ie manual hubs).

idanity

mr toytech

unless your in 4wheel the front drive shaft doesnt spin at all, there for it wont make any difference whatso ever. if you whant a little increase put some manuel hubs on to keep the front axles from spinning all the time.

MudHippy

Yeah, if he has manual hubs, unlocking them will keep the front axle from spinning. If he has ADD, nothing will stop the CV axles from turning because the hubs aren't unlockable. The front driveshaft isn't really connected to the differential when the ADD equipped rigs aren't in 4wd anyway. Hence the terms "Automatic Differential Disconnect". What's disconnected from the differential is the driveshaft, essentially. That problem's already been solved on the drawing board. Where the drag occurs in these systems is with the CV axles and the differential itself constantly being turned by the front wheels.

881stGenRunner

think though for a second.

if the CVs are turning, what do they spin? - the R&P.
If the R&P is spinning, what does it rotate? - the front driveshaft

b.miller123

He's talking about rigs that have ADD, there is a vacuum actuatied thingy (technical term) that disconnects something in the diff to keep the front driveshaft from spinning the whole time that you are driving around in 2hi, when you shift to 4hi or 4lo, it reconnects the something in the diff, and (obviously) shifts the t-case to send output to the front also, and ADD trucks/4runners have drive flanges instead of hubs

I don't know if any of that made sense, as I don't know exactly how the ADD system does what it does, but trust me, the front drive shaft doesn't spin unless you're in 4wd





now as for what will happen if you remove the front drive shaft, you'll get a little dirty, you will still be able to shift into 4wd but it wont help much, and then last but not least, a whole lotta nothin'

If it really matters to you the 1 mpg you might gain, then remove the whole front axle/driveshaft/cv's, and while your at it, pull all your seats and carpeting and anything on the interior you don't need to get down the road

881stGenRunner

okay, cool thanks for the clarification. my 88 came stock with Aisins so i really dont know much about the other systems (except they suck!) haha, j/k

MudHippy

If he has ADD when it's in 2wd the differential seperates the driver's side axle from the assembly ("disconnect" is maybe the better word because the axleshaft itself doesn't move. Just the splined collar connecting it to the differential). This allows the side gear on that side to spin freely. Hence the ring gear CAN NOT be turned by the other axle. UNLESS said ADD axle was spooled/welded/otherwise locked(LOCKED meaning side gears/axleshafts locked together).

Bottom line...

No, the front driveshaft doesn't spin when not in 4wd.

b.miller123

you want to sell them? J/K

Yeah the auto system really sucks apperently, I guess that those of us with ADD can put the Aisins in and have the best setup, as we could leave the hubs unlocked all summer, and then when there is a slight chance of needing 4wd, we can drive around all the time with the hubs locked and it won't do anything because of the ADD, and then we can shift into 4wd whenever we want w/o getting out of the truck, and none of the stupid backing up stuff that the auto hubs guys have to deal with

MMA_Alex

why not sell it, buy a 2wd, and pocket the difference. you'll get better gas mileage too...

elripster

With ADD, the drivers side shaft disconnects. This means that both CV's spin as well as the spider gears within the carrier. There is more drag on the driveshaft so it does not spin. I could, but it typically doesn't because the path of least resistance is to spin the spider gears and the disconnected part of the driver's side shaft the opposite direction.

Hope this clarifies.

Manual hubs means none of this stuff spins.

Frank

Kaydon

Sell your 4x4 and buy a 2wd?

mr toytech

if the front diff was connected to drinve shaft all the time the shaft would spin in 2 wheel drive with the truck totally off the ground. go try and you will learn something new. i dont care if its add or not the drive shaft is ingauged by the tranfer case not the front diff. the front actuator ingauges the drive shaft to the diff. and the hubs connect the front axles to the wheels. there for the front driveshaft never spins unless the transfer case is shifted to 4wheel.

f4stunna

sell the runner and get a car that gets 30+ mpg

thook

Keep your 4x4 and get a better job.