Diff locks

[Brandt]

I just replaced both of my Eaton diffs with "lockers". Now I need to hook up air and learn how to use them. What are the do's and don'ts on using a diff lock (as it relates to Eaton rears).

1) can I engage while moving? (in a straight direction)

2) Can I engage at any speed??

3) If I have just 1 diff locked, can I turn??

4) what will shorten the life of the locker?

Any tips on how to plumb these in would be appreciated. I have been told to run one air line and lock them in together. I have been told to tie the front diff in with the inter-axle lock. I have been told to run 2 separate air lines to allow me to engage the front OR the rear OR both locker(s). I have been told to tie both lockers into the inter-axle lock and when I though the switch - everything is locked!

PS

Can I get a similar set up for Mack top load diffs?

[Joe Ditchkus]

I have Rockwell SSHD-46,000 in my truck. They have separate switches for each axle and power divider. As far as trying to turn with them all locked in it takes a wider area.Joe D.

[AZB755V8]

Have Rockwell lockers in the Superliner. Two switches, one for both axle cross-locks, other for inter-axle, (front diff to back diff), Don't know why you would do any other switch setup. Turning radius is greater with things locked together. Those lockers are pricey and can be hurt kind of easy. Take care of them.

Mack has the peanuts in the rear diff to get them to lock but not standard in the front. Mack does have inter-axle air lock, common to have.

[HeavyGunner]

Don't engage them while spinning, in the mud when you have everything locked in use the Jake brake to help you turn. Turn your wheels in the direction you want to turn and let off the throttle so the jakes come on. This will pull your front end over. With a little practice and finesse you don't lose much momentum and you herd the truck where you want it to go. Obviously this should only be done at relatively low speeds. Good luck.

[j_martell]

I have always preferred have each lock on its own switch (front and rear cross locks and power divider), but the Mack I'm in and the Volvo I was driving for the feed mill both have the cross locks on one switch, and the power divider on another. The Volvo was plumbed so the cross lock switch didn't get air until the power divider did, which made for quick engagement, just one switch and its all locked up.

DO NOT engage while spinning ANY wheel.....anticipate you're gonna need em and hit em before you start loosing it. On soft ground (snow, ice, mud, loose gravel) and empty I notice very little difference in turning, as the back is light enough to just let the tires "burn", loaded , they both kinda want to plow lol.

I would avoid using at speeds greater than about 40km/h (whatever that works out to in MPH), just the way I do it. If I can manage over 40KMH then the conditions aren't crappy enough to be locked up. Also, careful with the the engine brake, it'll slow ALL the drive wheels and make for an exciting ride, with open diffs, a few wheels may keep road speed, which will help to hold a straight line.

[Brandt]

Thanx guys. I'll get them hooked up on separate switches. Good point on - if conditions are good for 25 MPH, then I shouldn't need lockers.

I've heard about the "peanuts" in the Mack diffs, but can't find a whole lot of detailed info.

[Nobody454]

just remember that with all the switches locked, everything touching the ground is trying to spin, I think it's much easier to break something driveline related with the lockers all on. I have full lockers on my Pete, but I only use them to get "OUT" never "IN", if you know what I mean

[m16ty]

Thanx guys. I'll get them hooked up on separate switches. Good point on - if conditions are good for 25 MPH, then I shouldn't need lockers.

I've heard about the "peanuts" in the Mack diffs, but can't find a whole lot of detailed info.

On the trucks I've seen, the peanuts are for locking both rear tandems together, sort of a automatic locking power divider, if you will.

They may also have them for locking the differential side to side but I've never seen it.

It works on a "overrunning clutch" principle. When one tandem starts moving so much faster than the other (as in one tandem in a spin out condition) it will lock both tandems together. When the tires quit spinning it will automatically unlock the tandems.

[kt_Engineer]

Mack Axles come with standard Power-Divider where as the Power-Divider Lock-Out (PDLO) is an optional feature. This is the peanut lock-out as mentioned above and locks-out the differential action between front and rear-driven axles by flipping a switch in the cab. PDLO is available on CRD92/93, CRD125/126, CRD150/151, CRD202/203, CRD95/96 and older carrier series.

The Inter-Wheel Diff Lock/IWDL (locking out left-side wheel to right-side wheel) is accomplished through a fork, clutch and diff half with extended spline. This is comparatively new feature and is only available with the newer series of carriers (i.e CRD150/151 introduced in 2009 & CRD125/126 introduced in 2012). IWDL is again an optional feature.

Mack Axles also offers a Inter-Wheel Power-Divider (IWPD) which use a similar peanut mechanism as Inter-Axle Power-Divider and automatically transmits 3 times the torque to non-slipping wheel (when on slippery surfaces). IWPD is also an optional feature.

The IWDL is purposely restricted to not work above 25MPH. The Vehicle ECU is pre-programmed to not exceed 25MPH with diff. locks are engaged. IWPD has no restrictions as such and works at any speeds. Only dis-advantage with IWPD is if one of the wheels has zero traction then the other wheel will see 3xzero torque (hence that axle will not move). IWPD in combination with PDLO and 6S6M (6 Sensors 6 Modulators) will offer superior drivability than any other options would offer.

Edited January 8, 2016 by kt_Engineer

[Brandt]

I have the PDLO switch for my CRD92/93 axles. I was wanting a left to right lock, but it looks like I'd have to get a set of cut-offs.