What is "power-shift"

[davesisk]

What is \"power-shift\"

Hi Folks!

I noticed that some of the larger Yanmars have something called "Power-shift" that (to my understanding) allows you to switch between forward and reverse in the same gear range without having to clutch. I'd assume this is a seperate lever from the gear range selector.

How does this work? I'd assume there's something like a fluid torque-converter somewhere in the tranny that allows you to shift between forward and reverse without clutching? I've read a bit on "shuttle-shift" that allows you to do the same type thing but requires clutching. How is this mechanically and functionally different? Any opinions about how it compares to hydrostatic drive? Just curious...

Regards,
Dave

 

[rockyridgefarm]

Re: What is \"power-shift\"

Actually. My 186D is hardly large. I have Powershift. It has 3 gears plus reverse for each of the 3 ranges. No clutch is required. You can hurt yourself good going from forward to reverse. I doubt the tractor ever cares.../w3tcompact/icons/grin.gif

My manual has a diagram of the clutch pack that does the magic. And that it is

 

[JeffRey30747]

Re: What is \"power-shift\"

I always try to give mine a brief rest in "N" before moving directly from "1" to "R" without clutching in order to minimize the stress on the operator. /w3tcompact/icons/wink.gif

 

[rccoyote]

Re: What is \"power-shift\"

HI, Dave Not exactly sure of the mechanical set up on the power shift(have had no trouble with mine), but yes, it does have a seperate lever. On some of the models i believe it is on the deck somewhere(not positive on this) and on others such as my 1820D it is on the colum. It does allow "shuttle shifting" or shift on the fly...in a specific gear range. My nieghbor has a kubota with hydrastatic tranny and we both seem to agree that we both prefer the power shift. This is strictly our opinion on this matter. The power shift allows for a much more varied gear selection for a specific purpose. Example...I was using mine with power shift and he was using his with hydro, we were doing some FEL work moving and loading some manure. I chose second gear in my gear ranges(clutching required) and he chose low range on his kubota. moving in to the pile we both had the power to get a scoop, but i could downshift in powershift(no clutching) to 1 and dig deeper and work my bucket to achieve a larger load. on reversing it was about the same speed, he just heeled it and i just flicked my lever in reverse.Getting the load to the trailer and getting it dumped was where the powershift shined. I could flick from reverse to 3rd and be at the trailer dumping while he had to stop and get his tranny in hi. A couple of times i needed low range to get some really gooey stuff and i could still back out and head for the trailer in 3rd gear power shift, low transmission range. Attached is a picture of my powershift lever and location. sorry so long winded, hope it gives you some better (if small) understanding of powershift.
rccoyote

 

[davesisk]

Re: What is \"power-shift\"

Cool, thanks for the posts, you guys. One more question: is this "clutchless shuttle-shifting" feature typically called "powershift" for other brands (not just Yanmar)? If not, what other names is it known under?

Regards,
Dave

 

[rockyridgefarm]

Re: What is \"power-shift\"

Well, It'll have lot's of names when you're used to yours, and you get on a friends tractor that USUALLY requires the use of the clutch/w3tcompact/icons/grin.gif Seems the tractor is the first to tell you. Come to think of it, I'm not allowed to tell you the name that the friend calls it. Not here on a family friendly site...

 

[DavesTractor]

Re: What is \"power-shift\"

There is no torque-converter, but the transmission has it's own hydraulic pump (internal) and hydraulically operates clutch packs. No converter means the transmission runs cooler, but it also means you cannot stop in gear without pushing in the clutch, or slipping the tractor into neutral before you come to a stop. I don't know of any other tractor that has this set-up. I know some of the Komatus and Mitsubishi dozers have a very similar set-up. All YM Yanmars that end in 10 or 20, and all of the FX series are power-shift.

 

[EFC]

Re: What is \"power-shift\"

Shuttle Shift is just a hydraulically shifted synchronous gear tranny. There is no magic and nothing fancy about it. That is why they tend to last forever. There are many manual shift synchronous transmissions that do the same thing. It was originally designed to give the tractor a live PTO.

 

[htiek126]

Re: What is \"power-shift\"

Do any of the F series standard shift Yanmars have a synchronous transmission?

 

[DavesTractor]

Re: What is \"power-shift\"

The regular F series (non-FX) are all synchro. Shift them like a hot rod!