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Discussion Starter #1
I've been messing around with the APS feature on a JD 8420. It will downshift for me (say from 10th to 9th) but refuses to upshift (9th to 10th).

I've tried everything and can't figure it out. Any ideas?

-Leave this here, Alex
 

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Discussion Starter #2
Yes, doing tillage work. The Deere works just like the Cat you describe. It downshifts just fine (to keep the motor from lugging too much) but when engine RPM's return to normal it won't upshift. I'll mess around without a load sometime and see if it works.

This feature would be a lot more useful if it would upshift.
 

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Oops, you mean to tell me the green guys messed up, I'm sure their marketing department can make something good out of it!!!! they always do.
 

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It will need to see 2050 or 2100 rpms for a few seconds before it will upshift.
I think Deere has the RPMs set too high on their APS. I don't like using it as it keeps the engine reved too much, means high fuel use.

Cat MT 745 will downshift at 1675, upshift at 1850-1900.
 

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Most of the transmission software from JD sucks!!!!!!
Why they don't want the engines to run at their peak power and fuel effiecient RPM's is beyond me. My 7920's IVT software is not anyware near making that tractor as efficient as is could be.
 

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Discussion Starter #6
[One year later!]

I'm not sure why APS wasn't working last fall but it's working now. Basically you run the tractor full throttle in whatever gear you want then press the Automatic Power Shift button to turn the system on. At 1900 RPM's the tractor will downshift, it will do so again at 1700. When conditions improve and the tractor can sustain 2200 RPM's it will automatically upshift until you reach the gear you started in.

I've found this feature to be very useful when pulling the chisel plow on hilly ground. See my post at http://combineforums.proboards42.com/ind....read=1194619479

APS gets cancelled if you press the clutch or shift manually. In that case just hit the resume button on your console and away you go.
 
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