I dunno dude. I was taught...long before I ever left the ranch, that the "johnnie bar" was good for two things. Checking your brake lights, and holding your truck in place while you held the bar down with your hand, and used the clutch and throttle to get the loaded truck and trailer started on a steep hill. :thumbsup:


Once I left the ranch....I was taught to check the brake lights with the "johnnie bar", then once that was complete....never touch it again, that all brake action was with the foot treadle. I have ALWAYS pulled the knobs on the dash to park, so I have never had to worry about the type situation Fredog started this entire post about....a run-away truck and trailer!


Back on the ranch, I was also taught to always shut a truck's engine off, with the brakes set and the transmission in "granny" or "reverse".


1973 was a long time ago. :tears:


I am not mechanicly inclined. I don't care what "color" lines are. I just care that they work properly and do not leak. Please forgive me.

 

The thought has crossed my mind many times, that if they tested us on the equipment, and those that flunked would have to sit on the bench, they'd put far more of us out of driving than they will with CSA 2010. The differential lock is another part of the equipment that many do not understand. It does not give them "POSI-REARS". It only means they will have 2 wheels spinning, instead of 1. While it is meant to improve traction, it does not lock the axles.

 

Actually, that's the "power divider lock" that you're speaking of. It locks the inter axle power divider, and just as you said, instead of having 1 of the 4 drive wheels spinning, you will now have 2 spinning(1 on each drive axle).

A true "differential lock" is available on some tandem rears, this will lock the differentials from side to side when engaged, and when locked in conjunction with the power divider lock, you have all 4 tandem drive wheels locked together. You'll either get unstuck, or all 4 drive wheels will be spinning. Don't try to drive on a hard surface with it all locked up, or steering is next to impossible, since all 4 drive wheels are pushing you straight ahead with no differential action possible.

We have both the power divider locks, and the differential locks on the trucks where I work. Ours are on Meritor rears.

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That would sound like a special application. I know that they have them in the far north in Canada. The vast majority of trucks on the road in this country do not have the other switch to lock both sides of the same axle. Only the differential between the two axles. I can imagine the steering would be next to impossible, but I was always told that if you lock both sides of the axles on a bare surface and try to turn, you'll twist off an axle, if you're loaded.

In the past, there has been a few discussions about the inter-axle differential lock. More than a couple of people have been under the wrong impression about them.

 

Dump trucks and heavy haul semi tractors.

Yup. Something has to give!

For those that may have questions,here's a PDF explaining the whole thing, inter axle differential, driver controlled diff lock etc.

http://www.meritorhvs.com/MeritorHVS...nts/TP9579.pdf

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That wouldnt be good in a dump truck when your being pushed by the paver i use it all the time for that.

 

Aw C'mon, there's no better "entertainment" than watching the paver crew go ballistic as you roll out of the hopper and dump a couple yards of mix in front of the paver!!!!:smokin:

:lol:

 

Then can go crazy when you roll out of the paver:lol: LOL.


I was on a job about 5 months ago and one of the drivers never dumped in a paver before. He rolled out like 3 times so the gave up on tryin to push him. He just dumped in the paver and pulled up for the rest of the load. After he was empty they sign him out and told him not to come back intill he knows what he is doing lol.

 

except when you forget to let the bed down and pull away and tear the rubber flap off the spreader