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Discussion Starter · #21 ·
The highest gears in a transmission are used to allow relaxed and efficient low engine speed at high road speed, not for top speed. Most cars with more than four gear ratios (in a manual) hit their highest speed in something lower than the highest gear. Continued high speed within the normal operating range are not a concern with an electric motor, so I don't see an issue with losing the upper gears.

With an OEM EV motor such as the one from a Leaf, if you used the stock transmission you would never get past second gear, because the motor should be run so much faster than the original engine. With a motor like this, omitting the transmission is an issue with losing the lower gears, not the upper gears.
Thank you, i have never had anything to do with gearing (or engine swaps, etc) and i'm trying to get my head round it
 

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Gear ratios of stock truck:


12345HiLoAxle
3.4772.0371.31710.821.2952.3673.363
For comparison, a Leaf has reduction ratio from motor to wheels of about 8:1. If you used a Leaf motor with the stock transmission and axles, given the ratios reported above, you would need to be in second gear to get close to the same ratio (2.037 x 3.363 = 6.85) with the transfer case in high range, although the wheel diameter needs to be considered as well (larger tires need more gear reduction). The Leaf can go to about 150 km/h (90 MPH) with that gearing, and I assume you wouldn't want to try to go faster than that in the Fourtrax, so you would never need to shift to even third gear.
 

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Discussion Starter · #23 · (Edited)
For comparison, a Leaf has reduction ratio from motor to wheels of about 8:1. If you used a Leaf motor with the stock transmission and axles, given the ratios reported above, you would need to be in second gear to get close to the same ratio (2.037 x 3.363 = 6.85) with the transfer case in high range, although the wheel diameter needs to be considered as well (larger tires need more gear reduction). The Leaf can go to about 150 km/h (90 MPH) with that gearing, and I assume you wouldn't want to try to go faster than that in the Fourtrax, so you would never need to shift to even third gear.
Thank you

Found this, very handy, might be useful to others
Gearing Calculator | RPM and Tire Diameter to km/h - mph with Shift Tracer

So keeping my rear diff and transfer case and using the Hi speed of the GS450H i would need an motor rpm of 7200 @ 75mph and 5310 @ 55mph (more my speed)
 

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The Leaf can go to about 150 km/h (90 MPH) with that gearing, and I assume you wouldn't want to try to go faster than that in the Fourtrax, so you would never need to shift to even third gear.
I'd say that's advantageous because he can get away with fewer batteries if that's the case. Depending on whether the Leaf gets grouchy or not about being fed the wrong voltage. The motor is fine, depends on the inverter.
 

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I'd say that's advantageous because he can get away with fewer batteries if that's the case. Depending on whether the Leaf gets grouchy or not about being fed the wrong voltage. The motor is fine, depends on the inverter.
It's true that if you don't need a wide speed range, you can use less voltage with the same motor and only lose high-speed performance that you wouldn't be using anyway. With a multi-speed transmission, high road speed can still be handled by shifting to a higher gear, so the motor turns more slowly and doesn't need as much voltage.

And I agree - controllers and inverters are designed to work with a specific range of voltage input, so going too low won't work at all - not because the battery can't supply enough power or the motor wouldn't work with the lower voltage (it gets lower voltage most of the time anyway), but because the internal circuit design isn't appropriate.
 

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You should be fine eliminating the transmission altogether, since the Leaf will spin close to 10,000RPM, so no issues revving the F out of it all the time (get ICE RPMs out of your head and the stuff Matt wrote on transmissions, after stating he was not expert, was mostly nonsense, especially the part about an electric motor having plenty of torque....it does, if you GEAR IT DOWN).

You can get manual locking hubs for that vehicle, so you should be able to run around in low all the time, since it's got a geared t-case, and the ratios will still be such that you'll exceed your tires' speed rating...in low, lol. You go mudding, you lock the hubs by hand - meh....worth it given how simple the drivetrain has become, how much weight you've ditched with your original trans or with that hybrid's expensive boat anchor slushbox a lot of people are all starry-eyes about.

All info on RPM & your gearbox are according to five minutes of talking with Mr. Google about Leaf motor RPMs and Fourtrak xfer cases.
 

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You should be fine eliminating the transmission altogether, since the Leaf will spin close to 10,000RPM, so no issues revving the F out of it all the time...

All info on RPM & your gearbox are according to five minutes of talking with Mr. Google about Leaf motor RPMs and Fourtrak xfer cases.
Did Mr. Google tell you what input speed the Fourtrax transfer case can handle while in low range?
 

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It makes no sense to me to make general statements about the amount of torque produced by electric motors or engines, given that there is an effectively infinite variety of both. The relevant point is that any source of torque needs to be considered in the context of any multiplication of torque by gearing (or chain drives or belt drives or whatever) between the source and the wheel.
 
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