Long distance " Sweet Spot" M35A2

[stumps]

Okay, so I've heard quite a bit about the lockouts, and pulling an axle shaft. I'm not sure about how the lock outs help??? Do you run with them open or locked in? And I would assume with pulling the axle shaft you would pull the passenger side as that is the powered one, correct?

Differentials confuse a lot of people. Although it appears from a diagram that there is a driven and a non driven side, it isn't really that way. Unless the differential is broken, neither axle shaft is directly connected to the ring and pinion set. The ring and pinion set drive a spider gear carrier, which drives the axle shafts.

Differentials are designed so that the average of the rotation rate of the left wheel and the rotation rate of the right wheel is equal to the rotation rate of the propeller (drive) shaft divided by the gear ratio.

Yuck! Word problems!

Raverage = ( Rright + Rleft ) / 2

and that leads to:

Raverage = Rdriveshaft / Gearratio = ( Rright + Rleft ) / 2

If we assume, the propeller shaft is spinning at 100 RPM, and the gear ratio is 4-to-1,
the average rate the wheels spin (Raverage) is 100 RPM / 4 = 25RPM.

That leads to some interesting conditions. If the left wheel is stopped, and the right wheel is jacked, the right wheel will spin at 50 RPM, so that the average is:

( 50RPM + 0 ) / 2 = 25RPM.

And if the right wheel is stopped, and the left wheel is jacked, the left wheel will also spin at 50RPM, so the average is again:

( 0 + 50RPM ) / 2 = 25RPM,


And if we are going in a turn, and the right wheel is turning at 30 RPM, the left wheel will be spinning at 20 RPM, so the average is once again:

( 30RPM + 20RPM ) / 2 = 25RPM.

And another interesting condition happens if the drive shaft is stopped, and both wheels are jacked up, and you turn the right wheel at 25RPM forwards, the left wheel will turn at 25RPM backwards!

-Chuck

 

[USAFSS-ColdWarrior]

Stumps/Chuck....
Thanks for that concise explanation.

I'm sure that a number of readers will be outside jacking up their axles to "demonstrate" the cause and effect TONIGHT

GOOD JOB

 

[stumps]

Do lockouts help? Yes, and no. They only help fuel mileage to the degree that they stop the gears in a differential from spinning, and to the degree that they stop tire scuffing.

First, lockouts should not be used on the front axle of a truck that has a sprag transfer case.... it will do harm, not good. Front lockouts only help on air shift transfer cases.

If you put one lockout on a front axle, it will not stop the gears from spinning, so it will not help your fuel efficiency. Further, one lockout, when you are in rear wheel drive, will probably cause the locked out axle to spin backwards... depending on the friction in the transfer case. It won't be very good for your differential.

If you put two lockouts on a front axle, it will stop the gears from spinning if your transfer case is in rear wheel drive. This will give you the best improvement in fuel efficiency, and should improve the life of your front differential, the universal joints, and your front tires. It will also reduce tire hopping when you make tight turns.

If you put one lockout on a tandem axle, it will not stop the gears from spinning, so it will not reduce your differential losses, and probably will do nothing for your fuel efficiency, but, It will, however, break the direct drive connection between your front and rear tandem axles, and will reduce tire scuffing in turns, and scuffing caused by dissimilar sized tires. This reduced scuffing will make steering much easier, and your tires last a little longer.

If you put two lockouts on one of your tandem axles, it will not stop the gears from turning, and will do nothing for you over using one lockout, other than empty your wallet.

If you remove the center drive shaft, disabling your rear tandem axle, it will not stop the gears from turning and will do nothing to reduce the differential inefficiencies... it will, however, reduce tire scuffing, and that will make steering easier.

If you remove the center drive shaft and put two lockouts on the rear tandem axle, it will stop the gears from turning, and it will improve your fuel efficiency... It will also make your deuce effectively a bobber with poorer tire grip (due to somewhat lower weight on the tires). It is fine if you value appearance and efficiency over function.

-Chuck

 

[stumps]

Stumps/Chuck....
Thanks for that concise eplanation.

I'm sure that a number of readers will be outside jacking up their axles to "demonstrate" the cause and effect TONIGHT

GOOD JOB

If you do, don't forget that the tandem axles are tied together by their center drive shaft, nothing will turn unless at least two wheels are jacked up.

-Chuck

 

[jblack6527]

I thought we were talking about highway driving not cross country becuse CC driving is the only way any of this would be a issue. Short of pouring cloraxx under the tires ( or iced road ) I seriously doubt you could get the deuces tires to spin on a prepared surface even with the intermediate shaft out. I've known several people that have pulled the intermediate shaft and they never bragged about spinning tires. Pulling either of the two rear axle shafts would be quicker than pulling the drive shaft but what would you use to cover up the now exposed hub

Yes sir the Deuce will spin on take off with the intermediate shaft taken out. Any time you take off on a hill, or with some dirt/gravel on the road surface you will spin. I'm not saying you will burn the tires off, but it will spin before moving.