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Discussion Starter · #1 ·
Re: 9120 Transmission

I agree that a powershift would be nice. Just a thought though... After taking an 8010 transmission apart at school, I was very impressed with how rugged and large the gears/bearings/shafts are compared to, say, a 2588 tranny. If the thing holds together as well as it looks like it will, this salary paid mechanic will be happy
 

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Re: 9120 Transmission

Powershift/CVT thats all fine and dandy but what will it add to the cost o the machine and how do you get the power from the engine to the transmission. It will take hydro or hydraulic power to do it anyway since a mechanical connection would be way to complex.
Unit has to come to a stop to shift likely due to no sychronizers and straight cut gears I would expect that a missed shift with all that weight if the bin is loaded would be very destructive to the transmissions internals. The electric shift is nice though versus the lever in the cab like the old series or Deere.
 

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Re: 9120 Transmission

bucksnort
I guess deere is going to have a powershift that is pretty much seamless in their new combines. If you were to have a powershift in the 9120 tranny then you would either need a separate pump down there or more hydraulic lines. Now, I don't think you'd notice anymore lines on the AFXs, but to run multiple clutch packs in a combine transmission that is shifted once or twice a day (up in Canada at least) seems a little overkill. A CVT is going to be a much better step than any powershifted combine transmission.

redhat
Case runs a shaft to drive the feedhouse on the AFXs. would be pretty simple to run a second driveshaft into the tranny and run the CVT right there. I'm pretty sure that 2 90 degree gearboxes aren't too complex for a Case engineer to figure out. They sure like them everywhere else!
 

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Discussion Starter · #8 ·
Re: 9120 Transmission

As a mechanic, I just hope that they very carefully weigh the benefits of features vs. the complexity that they add. The AFX series is quite complex now, but most of the complexity is a result of features that are in demand and add value - CVT rotor, CVT feeder, electric concaves and sieves, electronic hydro system, electronically shifted transmission -- are some examples.

Everything added is a wear point and statistically reduces reliability. A solid, reliable machine is something that most customers would not give up for excessive bells and whistles, I would think.

Would a two speed hydro be the solution? Would be kind of like a T/A and would add very little cost / complexity...
 

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Re: 9120 Transmission

RWA won't help with hills. Its not a traction issue, its a gearing/torque issue. In order to get the top speeds needed for the road the transmission has higher gears. These higher gears reduce the torque available to the wheels and the hydrostat must bypass. A RWA would probably make it worse at this point because there would be more demand for oil from the hydro.

This is a situation where a powershift would be benficial, for one would get the torque from 3rd gear but without having to stop.
 

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Re: 9120 Transmission

Acutally, yes, it will. Running a mudhog rear axle on a 2388 in 3rd gear (were you can flip in/out of RWA) is pretty nice for crawling up hills.

The way the oil valve works on a 2388, it does give you more torque (and half the speed). It's not like a mechanical 4wd link on a truck.

-Lance
 

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Re: 9120 Transmission

andy
Running with rwa engauged in any gear does in fact reduce top speed in that gear causing a reduction in torque needed to move the combine achieving the similar result as shifting down.
I'm not saying powershift would not work but changing softwear to let us us rwa in 4th would cost almost nothing.
 

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Re: 9120 Transmission

I do not understand why case does not let us use rwa in 4th gear . We have to stop lots of times to shift in or out of 3rd to pull hills or out of fields .This is really bad when your dealing with traffic. Using rwa would be like shifing down in these situations. Other brand combines we had before let us do this.
 

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Discussion Starter · #13 ·
Re: 9120 Transmission

By turning rwa on, you are effectively putting the front drive motor and rwa wheels in a parallel hydraulic circuit. This effectively increases the hydraulic displacement of the system. When the displacement is increased, the required pressure to meet a certain load is decreased. When you flip the switch on and suddenly slow down, this is due to the increased displacement (the rwa) being added to the system. The pump is still pumping the same volume, it just needs to be shared with the front and rear. If you had a gauge on this system, you would see a pressure drop. With the pressure lower, there is more room before the hydraulic overpressure relief kicks in -- hence more torque.

Think of two hydraulic cylinders -- a one inch diameter one, and and five inch diameter one. Given the same pump flow, the 1" will extend quicker, but have less force. The 5" will have a lot more force, but will take more oil to extend (and take longer).

As to why case lock it out in 4th..... not a clue!
 
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