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Size comparison:....

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Impressive, but totally overkill. I like it! None the less, I just don't see any need for 9 gears. Three seems about right, and when I had a 3 speed truck, I found myself most often running in 2nd gear. It was a good in between gear. Now my latest truck has a really simple one speed planetary gear head motor and that doesn't bother me one bit. It's more compact, stronger, and can handle all kind of torque. Yes, I gave up shifting the gears, but that's one less thing to worry about, it frees up a channel on my radio, and I just never found myself shifting gears all that much anyway. It's fun for a little while, but if your driving your truck in a tight place, about the only place you do get up to top speed is in an open parking lot. Unless you've got some aux. gear reduction.

I wonder how much backlash that 9 speed has. Tamiya's 3 speeds have way to much.

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With metal gears and synchronizers backlash can be dramatically reduced because the slots in the gears and the drive dogs on the sychronisers are cut into a solid blank and can be made any size.

The plastic gears and sychronisers Tamiya use are injection molded and cross sections of injection molded items must be kept thin or the plastic will shrink considerably when it cools. Therfore the drive dogs on the synchronizers are narrow and the slots in the gears are wide (the land in between the slots is narrow). Resulting in lots of backlash....

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9 speed alternate mounting positions..

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by the time you shift thru all 9 gears, it will be across the stateline.:D

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Even with these pics you can see its nearly impossible to have an interior, especially in a day cab. I really dont even see a way in a conventional or an extended sleeper without figuring out a way to lay it on its side.

--Dan

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I will have to say having a interior was not a priority when designing this transmission. For me personally it is not a priority at all. I don't see the need to make the cab comfortable for a 5 inch hight plastic man. The cab interior is far better utilised for equiptment. If cab interiors are a priority it may be more suitable to build a static model.

The transmission connot be laid on its side. It contains automatic transmission fluid. It would make a awfull mess, not to mention oil up the motor......

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It would not allways be necessary to shift through all 9 gears.

As shifting is concerned i would forsee that the 9 speed would essentially be shifted by selecting a range (high, mid, or low) with the right stick on the control in the vertical plane (right horizontal of course being steering) and then shift the gears 1st, 2nd and 3rd as normal with the left stick on the control in the horizontal plane, only changing ranges as the overall situation requires, rather than starting in 1st / low and shifting all the way through all the 9 gears to top. So in some situations you would start in High range / 1st and not even look at the 6 gears below that. In a crawling situation you may decide Low range is suitable and then start in either 1st, 2nd or 3rd and the same for Mid range. Choose a range then choose a gear. Having said that you can also start in low range and shift up through the ranges to high range selecting 1st, 2nd or 3rd at the same time. Almost endless possibilities.

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I am working on a Cat V8 engine cover to go over the front of the transmission to improve the engine bay looks.

This is the extension through the front firewall into the engine bay with the 9 speed moved forward.

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One difference between 1:1 and our equipment is the prime mover RPM. Diesel engines have a very narrow power band and low max RPM, requiring multi-gears to match available power/torque and road speed. Our electric motors have a considerably wider RPM range, depending on turns, etc. I chose a low RPM 85t motor for my Payhauler. It turns 5200 RPM at 7.4V, so is about double the diesel engine RPM in the real truck. By using a 3-spd trans, I just about replicate prototypical road speed, since the 1:1 had a 6-spd trans. Lower turn motors spin a lot more RPM, reducing the actual need for a many-gear trans - use of one speed or a 2-spd trans works just fine since we seldom see anything like scale speed (70 MPH) with our trucks.

But then, nothing beats shiftin' those cogs 9 times going across the room! To each his own - just have fun doin' it.:p:p

Ken

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Yes Ken.....you got it...... to each his own...!!

I've been experimenting with 12volt RS555 motors running on 7.2 volts.
In that configuration they act more like the diesel, it's more of a challenge to drive, and more realistic, they drive like a truck instead of a sports car.....the spin off is the batteries last for ages...

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Here is the gear ratio chart for anyone interested.