Pre-Trip Inspection & Drive Shaft

Discussion in 'Trucking Industry Regulations' started by deathB4decaf, Jul 15, 2020.

  1. deathB4decaf

    deathB4decaf Medium Load Member

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    My drivers are on their way back with them. They said they will fully explain tomorrow since they won't get in until after closing today.
     
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  3. AModelCat

    AModelCat Road Train Member

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    That's the first problem, asking truck drivers. Most have never had a diff apart, don't know how it works but spew all kinds of BS they hear at the lunch counter.

    Driving with the power divider locked in with the driveline installed WILL cause binding issues and increased tire wear. With the interaxle driveshaft removed and power divider locked in essentially what you have is a single screw with a tag axle since there is no longer power transfer to the rear end.

    The only way the power divider is going to get damaged is if the driver sticks it in gear and lets the clutch out, realizes the PDL is unlocked and tries to engage the lock with the driveshaft spinning.

    That said, I have heard of some trucks using a single switch to engage power divider AND diff locks. That will cause issues unless the axle locks are disabled in that scenario.
     
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  4. dibstr

    dibstr Road Train Member

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    Some lock the rear shaft in. I had an 88 379 and had to remove the rear shaft when a u joint and yoke failed. Thought I would have lock it in to continue but nope, it pulled off the front diff.
     
  5. AModelCat

    AModelCat Road Train Member

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    Something's screwy there. There's basically 3 diffs in a tandem drive truck. Power is lazy, it takes the path of least resistance. Its all a balancing act between the spider gears in the 2 diffs and the power divider. Break any component in the path of power between the forward drive axle input yoke and any of the 4 hubs and the power will just spin the failed component. It is impossible to move unless you lock something in.
     
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  6. Long FLD

    Long FLD Road Train Member

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    Kind of forgot about this thread. I wonder how it all played out.
     
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  7. dibstr

    dibstr Road Train Member

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    I really hadn’t thought about it in years (It happened sometime in the early 90’s)and really wasn’t that curious about the whys and hows. But thinking about it now I do recall seeing a guy in a gravel lot who seeming had a clutch let off problem. I noticed after he tried moving a few of times he would scratch out with different tires on either axle. He was not locked in and again I wasn’t really curious enough to look in to it. In the past few minutes I googled it and the seemingly reputable sites (for instance California clutch and gear) offered the same explanation, which trashed my very limited understanding. Basically both axles are working all the time. They work kind of like either side of a single axle does, When one side slips the other gets the power. Locking in the interaxle differential doesn’t ‘engage’ the second axle, it locks the outputs to each differential so that they always rotate at the same speed.
     
  8. deathB4decaf

    deathB4decaf Medium Load Member

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    Okay, so we big boss is fighting with the transportation company over all of this. I spoke with the drivers about all of it after I looked back through the entire thread and looked some stuff up on the internet. Our drivers now understand the best way to handle when the rear drive shaft is missing and, per the awesome advice on here, was able to instruct them how we can bring the trucks back without worrying about the rear drive shaft. There are a couple more trucks to pick up that will be missing them, I almost guarantee it. Now I feel a lot more confident in my ability to advise them. One of our great mechanics went out to a few trucks with me and looked everything over, gave me some great visual understanding. This forum genuinely helps me be better at my job and has given me a huge respect for drivers and the trucks we transport. Thank y'all, from the bottom of my heart.
     
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  9. Long FLD

    Long FLD Road Train Member

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    Why is the rear drive shaft missing in the first place? Why continue to bring these trucks back when it’s been stated that if there are issues that driving it without the drive shaft voids warranty? Why not inspect all the trucks and contact a driveline shop local to where the trucks are and just get them repaired since they’re going to need the drive shaft eventually? What happened with the truck that was damaged?
     
  10. deathB4decaf

    deathB4decaf Medium Load Member

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    No information on the truck that was damaged. I asked and was shut down.

    With me being the "Transportation Coordinator", I am told to "do as I say". I get the trucks back here and then our mechanical shop takes over.

    When I discussed the situation with the powers that be, I was told that it isn't cost effective to have someone check each and every truck before we get them back here. What I have started doing is calling the location and requesting a pic of the rear drive shaft. If it is missing, I advise them that it needs to be placed inside of the vehicle before I send the driver to pick it up and to give me a call once they have done so. I'm not sure that the person who was giving me direction before 100% understood how to properly handle it. He's new to having a CDL and while very intelligent, he's not a mechanic nor could I see him working in the shop at all.

    I try and do as I am told but I have a bit of a rebel in me so I stopped asking them questions when it was nothing but frustration and spinning my wheels. That's when I came here instead. I got a lot better results here. Then I talked to the same person giving me instruction previously and laid out my "new knowledge" and he decided that would be cost effective and still get the trucks back here quickly.

    When we have someone check out the units before hand it can be costly AND it can set us back time wise. The last company I hired to check out one of my out of state trucks just never showed up and told me he just forgot. Which means I waited multiple days trying to get someone out there and in the mean time, I had other items come up on my schedule that I sent the driver on so he wasn't waiting. It was a dumpster fire.
     
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