Transmission and auxiliary transmission

Again no one is talking about can position

 

It’s all about driveline angles in the end. That’s why I made the comment earlier about Mack rears. They have less of an angle than other types. Simply because the carrier is pointed up.

 

Yes, I see what you’re saying. Yes a setback axle would provide a longer driveline because it would allow the engine to move further forward that I agree but axle position doesn’t change wheelbase which is my point. You mentioned turning radius, wheelbase is wheelbase. Turning geometry is a little different on a setback axle but that doesn’t change wheelbase.

 

Wheelbase is wheelbase that you are correct on. A sb provides for a longer frame for additional equipment while trying to compensate for maneuverability by moving the axle back. That’s what I meant. Whether I said that or not.

 

Yes that why I preferred my T800 to my 379, more room for my boxes and stuff without adding length.

 

As @johndeere4020 said wheel base is front axle to center of the rear axle group.

I specifically ordered a set forward axle because it allowed me to reduce my avall length to under 110’. Had I ordered a setback my OAL would have over 110’.

 

Late to the party. Yes everyone agrees on how to measure wb. I am curious to know how much longer a sb would have made you? Couldn’t have been much more than a foot. I do understand needing to be under 110 though

 

18” in the schematics I posted for the Petes.

 

I believe it was approx the same for my Western Star. I am 109 4 with my 26’ flat deck in

 

You can read the Spicer manual, it says 3 deg or under driveshaft angle is ideal, but will allow for more up to a point ( I’d have to look the manual back up to find the max allowed). The main cause of vibration is if the main and auxiliary shafts aren’t parallel. If you put a angle meter on most factory driveshaft setups, you will find that most exceed 3 deg.

A u-joint, operated at any angle, will cause a change in velocity to be introduced in the driveline, each revolution. If the main shaft is sitting at say 3 deg, and the auxiliary shaft is also at 3 deg, the velocity change introduced by the first joint will be canceled out by the second joint, and not send the velocity change on down the line. Of course, when the driveshaft angles get too steep, the velocity change can become too much and cause a vibration there, because the steeper the angle, the higher velocity change.

I did a mock-up of my auxiliary Friday. Due to having to miss crossmembers, the front shaft is running at 6 deg. The rear shaft is almost flat. I think I’m going to mount it there and see how it works. After I drill the frame for the mounts, it will be easier to raise the auxiliary with shims than it would be to lower it.