Diff lock vs inter axle lock

True. Use of the Jake brake, power divider, or differential locks aren't taught in CDL mills. You have to learn that on your own, or perhaps you are lucky enough to get a trainer that knows their stuff, but we all know how well that's working out.

Last year I made quite a bit of money one day. I was dispatched to bobtail about 150 miles from OKC to rescue a situation for one of our customers. It seems they thought if they sent one of their technicians to CDL school they could improve their service and save money.

The fresh new driver attempted to pull an 85,000 lb three axle trailer up a 20% grade on a dirt road. The drive shaft blew through the catwalk and embedded itself in the spool of cable on the winch.

A bulldozer was available to pull him to a relatively flat spot. I arrived to assess the situation and asked if he had engaged the power divider. "The what!!!???"

It took some time to rig chains and binders to take tension off the locking jaws to be able to tow the tractor four miles up to the fracking pad. Then I went back and hooked to the trailer and brought it up to position at the pad, with the young driver in the passenger seat. Along the way I explained use of the power divider, differential lock, and why you shouldn't just floor it to get up steep hills off road. He was appreciative.

Better training is needed.

 

I agree, better training is a must.

To get me to know some of this stuff and not say anything at all would be like asking a stone to stay silent on the last day.

That is another symptom when the Industry accepts tractors with just a tach and how fast speedo on them and nothng else at all. No wonder drivers cannot do much. What's next a push button from Windows installed saying fix me? /sarc...

 

I'll have to respectfully disagree. Though the smoky ones I've seen have been Cascadias, I think. Peoplenets in ours are mounted on the dash, obscuring the pdl, fifth wheel slide, and suspension dump switches. There have been two power dividers smoked here that I know of.

Our Volvos indicate on the dash when pdl is locked.

 

If it is a dry highway you will burn it up. It will have to be in I-10 or something with a awful lot of rain in season where it will work well keeping you straight when the steers hydroplane.

I miss the old trucks, 60 gauges telling you everything plus 40 toggles for this and that and power this slide that lock over here so on. Gives you all sorts of options in battle. Today's trucks have been stripped out with just a couple buttons. I rather make truckers smart, not stupid. Understand?

 

It's kind of sad how i'm still not clear on this but,

If you have a tandem axle tractor AND if you are on a completely flat and DRY road AND you are going straight, then all four rear wheels are putting out the exact amount of power?

 

I would be curious about the circumstances of having the power dividers "smoked". They may have been engaged during a spinout. That will do bad things for sure.

 

My old KW prior to this one had a Detroit Locker in the rear diff that locked up automatically. Only problem is that on sharp turns when going slow you could feel it locking up. Same thing happens on my Ford Falcon with 9" Traction Lock diff.
When I had the power divider locked in, you would have 3 wheels locked together with only one that would spin in the mud.

 

Yes. And when one wheel slips all the power goes to that one wheel.

 

Dump the air. Makes a tremendous difference when the traction is just a little slick or the ground just uneven enough to let one wheel spin.

 

What's the physics of this? Why does dumping the air increase traction?