How do you shift a sinchronist dumptruck transmission?

Answer 1

It's a little vague as to what your question is here. I'm a diesel tech and have over a decade of experience driving Class 8 trucks, and I've never heard of a "sinchronist" transmission.

Either you're trying to say "synchronized", or you're trying to say "unsynchronized". If it's a split range, twin countershaft transmission, it's probably unsynchronized. This would include the Eaton-Fuller and Rockwell 8LL, 9 speed, 10 speed, 13 speed, 15 speed, 18 speed, and 21 speed transmission, as well as the Super 10. These don't have a synchronizing gear, and you have to account for the timing. For a beginner, you'd typically be taught to upshift at 1500 RPMs. You would depress the clutch (just enough to disengage the transmission, but not enough to engage the clutch brake), shift it into neutral, let off the clutch, depress the clutch again, and come into your next gear around 1000 rpms. Personally, I prefer to upshift at 1900 RPMs, but you'll get the feel for this over time, as you gain more experience with engine power bands and such.

If you have a synchronized transmission (e.g., Eaton Fuller and Rockwell 6 and 7 speed transmissions, Volvo 14 speed transmission), DO NOT try to float these transmissions, ever! You will destroy the synchronizing gear if you do. They shift like a regular car transmission - get to your desired RPMs, push the clutch in enough to disengage the transmission, go up to your next gear, let off the clutch.

As for shift patterns, I cannot say, as you didn't specify WHICH transmission you were referring to. Dump trucks come in all sizes from Class 3 trucks (e.g., Ford F350, Chevy/GMC 3500/Dodge Ram 3500) all the way up to Class 8 trucks (tandem trucks, tractor-trailers, etc.) and a wide range of transmissions can be found throughout, ranging from a regular five speed in an F350 to the unsynchronized MaxiTorque transmission to the Eaton Fuller 18 speed, and everything in-between.

Have you considered a truck driving school? And, if you do have a CDL already, how did you ever pass this road test for the company (assuming you've been hired on) without knowing how to shift?