Two questions I always forgot to ask that no one talks about

One of the earliest memories which I can recall, is of my Mama holding me on her hip, as we watched Daddy back the truck up the driveway. Growing up, my jungle gyms were the retired and/or wrecked hulks of parts trucks which populated the back yard. In a few, I would venture a guess that I put on a million miles behind me as I played trucker, on my way to such exotic places as, NYC, Baltimore or Dayton.

I WORKED beside my Daddy, on our truck and those of many, many others, doing just about everything from engine overhauls to body work and paint. At the age of eight, I fixed my first tractor-trailer tire (tube type, bias-ply, 20" Dayton three piece rim). The truck which I cut my teeth on, as a driver, my Daddy and I built, in my early teens. Starting with two chassis rails and scavenging parts from the relics in the yard. One month and one day later we were running the semi-metallic Emron emerald green, cab-over Frieghtshacker up the road.

My Daddy was an awesome mechanic and one hell of a truck driver. Being in total awe of my Daddy, I took what he told me as gospel. When we replaced the pusher tag axle set up, on the tractor prior to the one we built, with a full screw, what I posted above is pretty much verbatim how he explained to me how it worked and obviously I have carried it with me for thirty-five years.

As I have found throughout my life, gospel is not always supported by fact. Bender's second explanation made perfect since to me. As I am now understanding it, a disengaged power divider is basicly a differential linking the two differentials and an engaged power divider is akin to a spool type rearend linking the two differentials. Thank-you for the education and setting me straight. Now on to busting the next factually deficient, old school "gospel"

 

Thats an awesome story, HR.

 

A real question that shoulda been asked is should I dump my air bags on my truck before dropping a trailer at sni

 

The way I did it was, pull the kingpin. Wind down the dollies, until you hear the air in the bags start to dump. Pull the tractor forward about a foot and flip the switch to dump the airbags. Get out and check that the dolly sand pads are not sinking into the surface the trailer is being dropped on. If they are, flip the switch back to air the bags back up, hook back up to the kingpin, wind up the dollies and find someplace else to drop the trailer. If the dollies aren't sinking into the surface, take a minute and update your logbook or other paperwork, then get out and check the dollies again. If everything looks good, get back in and flip the switch to air the suspension back up and pull out from under the trailer.

When I hooked to a trailer, I would back up to the trailer just before the 5th wheel touched the front of the king pin plate, dump the airbags, back about a foot and a half, get out and make sure the opening of the 5th wheel is aligned with the king pin (side to side and not past the locking mechanism of the 5th wheel). If it looks good, get back in and air up the suspension and slowly back, hooking to the king pin. Get out and check that the king pin locking mechanism is engaged. Then wind up the dollies.

 

I do know it beats up the tires , especially in city driving if you forget to disengage the device. Also, like A 4 wheel drive vehicle " engaged " when you don't need the assist , powering the additional driveline components has to take it's toll on the equipment. Simple physics. The red warning light or annoying buzzer is there for A reason. I drove A Mack that had an automatic traction control feature , but I am not at all knowledgeable as to how it functioned....bottom line , it was nice!You could feel it react to road conditions when needed , and then disengage. The tractor was A Vision , 460 HP , Eaton 18 speed , all comon stuff . It was A company truck that I really babied to keep it out of the shop !

 

First logical , comprehensible explanation I've ever heard. Very well done ! I once had A Mack , company truck , with no " obvious , visible " power divider engagement control. Our mechanic told me that you stepped on the brake to engage it. ? I am in A strip mine , stuck , and I step on the brakes to get " unstuck "? I tried going into neutral , stepping on brake ; leaving it in the " low " gear and idling , disengaging clutch , chanting there's no place like home , Toto........the loader operator laughed at me , declined to help , but did have the scale house call my employer and indicate I was clueless and was disrupting operations there . Never did figure that one out ; since I was ignored anyway. The corporate culture there was A general contempt for " company drivers " with " short hooded trucks " LOL ! And I'm not makin' this up ! My alter ego would be Schultz ...... "I know nothing, see nothing , sometimes I even forget who we are fighting" !
'

 

i usually leave ~ an inch gap (landing gear pads to ground), then dump or go,

5th wheels have diff heights, wanna take into consideration folks with low ones otherwise they have to wind down (could be loaded too) to hook up

 

This explanation is classic and very understandable, but one quick question, if all rear tandem tires are on slick surface and one tire is spinning which leaves the others stationary. If chains are placed on the spinning tire, will another tire then start to spin negating the effect of the chained tire. Also how would using just one chained tire effect the locked diff position if others were on slick surface.
Thanks, I have learned a lot from this line of posts.. Capt Dan

 

To the first question, yes, with only one tire chained another wheel position would likely spin and put you in the same boat until you provided equal traction to all positions.

Chaining one tire on an axle with the interlock in lock position would cause the power to that axle to go to the point of least resistance which would be the unchained side, causing it to spin. The unchained axle could have both pulling if they had equal traction or one spinning if they don't.

 

Nothing more frustrating than having the front right/rear left drive wheels spinning in mid air , over the holes I created trying to escape my predicament. At 63 , I have come to the realization that my torments are almost always A result of operator error ; and learning serves to emphasizes the vastness of of that which I don't know. Another observation is how absolutely certain I can be of being right ; like I would bet my life on my facts , and be so wrong ! Even with the 9 lives of A cat, I'd have been dead many years already !