Locking Drive Axles

[damianminteer]

Ive been told so many ways to lock a set of mack rears to give maximum traction and im trying to clear it up. My rears are 44k mack rears without a power divider and i use the truck in truck pulling and bobtailing only. Besides welding the penuts, is there any other way or is that it ???

[theakerstwo]

Check with mack or a gear builder. You can get a front unit like on some concrete mixer trucks that has a direct drive thru instead of having a power diver. I have worked on them years ago but can tell you what you need. I think the thru shaft is different as well as the imput on the front pinion will be all different as well as maybe the front seal and brg retainer.But alot of mixer trucks had them.

[slpwlker]

I might be wrong but I thought on the older Macks you could lightly touch the brake pedal to lock them all in. Am I wrong?

[rhasler]

I might be wrong but I thought on the older Macks you could lightly touch the brake pedal to lock them all in. Am I wrong?

What you are referring to will transmit power to the wheel on each axle with the least resistance and would be on a Mack differential without the air lockout on the power divider. The differential with the air lockout does the same thing, transmit power to the wheel on each axle with the least resistance, but does it at the flip of a switch. Both versions are an inter-axle power divider. The new 150 series differentials also have an available inter-wheel lock which divides power equally among all four wheels (when both switches are turned on).

[slpwlker]

What you are referring to will transmit power to the wheel on each axle with the least resistance and would be on a Mack differential without the air lockout on the power divider. The differential with the air lockout does the same thing, transmit power to the wheel on each axle with the least resistance, but does it at the flip of a switch. Both versions are an inter-axle power divider. The new 150 series differentials also have an available inter-wheel lock which divides power equally among all four wheels (when both switches are turned on).

It was something I remember my dad telling me about Macks with Mack rears when he had his B45

[Lmackattack]

I think what your dad was telling you was that macks automatic power divider. if you were stuck and spinning the wheels or just spinning the wheels on one axel, you tap on the brake pedal to try and get the power over to a diffrent wheel/axel and hopefully if it transers the power that wheels traction will get you out. I have used that trick many of times. some times it works sometimes not. need to go easy as its abuse on the drive line.

[slpwlker]

I think what your dad was telling you was that macks automatic power divider. if you were stuck and spinning the wheels or just spinning the wheels on one axel, you tap on the brake pedal to try and get the power over to a diffrent wheel/axel and hopefully if it transers the power that wheels traction will get you out. I have used that trick many of times. some times it works sometimes not. need to go easy as its abuse on the drive line.

Might of been. I did that loading a Mack mixer on a lowboy one time. Since I never did it, I didn't know what to expect. I think I stalled 5 times before I ever got on the trailer. I honestly don't know if it had a power divider either.

[Lmackattack]

If the power divider is worn out it may not kick in like it should. Remember all the power divider does is put power to the other axel. when its in you have 2 wheels with power. when its out just one wheel has power. thats not to say that both wheels of the same axel will spin but as soon as one wheel gets traction it stops and then power goes to the free wheel. this is where taping the brake pedal will sometimes stop that spinning "free" wheel and transfer it back to the one that has more traction.

only If the truck has a air operated diff lock. both wheels of that axel will fully lock in, other things come in to play but thats the basics

Most macks I drove had a automatic power divider and thats it. alot of trucks I drove with air ride had a manual powerdivider and a difflock for one axel. this gave you 3 wheels locked in and one wheel was left free to prevent driveline damage. However some trucks can have a powerdivider, and a diff lock for both axels giving full 4 wheel locking power to the ground.

any time a difflock is used it should be on soft or louse ground mostly in a straight line so not to put stress on the locked axel.

hope that helps

Trent