transmission types?

[Anonymous Poster]

I think I'm looking for a smaller 'mowing' tractor right now and hope to move up to a bigger one latter... once I really find out what I need. I'm stuck on types of transmissions....

1. I understand hydrostatic but are all 'automatics' really hydrostatics
2. And manual is old fashioned shifting
3. what's 'shuttle shift'?
4. Any other methods out there that I should know about?

Any comments or tips are most welcomed.

Wickman

 

[chrisjbell]

<font color="blue"> 1. I understand hydrostatic but are all 'automatics' really hydrostatics
</font>

No - a true "automatic" has a torque converter and uses belts to transmit power. A hydro uses valves and fluid only. BTW, I'd strongly recommend one - the JDs are great.

<font color="blue"> 2. And manual is old fashioned shifting
</font>

Pretty much. It means that you jerk to a start and then force the lever from gear to gear while moving . OK, a bit smart alecky, but you don't have a real clutch on smaller tractors - just that "brake/clutch" thingie. You pick a gear let the clutch out and go.

<font color="blue"> 3. what's 'shuttle shift'?
</font>

Shuttle shift transmissions can be mechanical or hydraulic. Mechanical shuttles require using the clutch to change direction, but they are synchronized. Hydraulic shuttles can be shifted with out using the clutch. Either way, these transmissions allow the operator to change directions with out stopping. You probably won't find these on lawn tractors.

<font color="blue"> 4. Any other methods out there that I should know about?
</font>

There are other options, but for a lawn tractor you're pretty much going to see either manual or hydro. I'm sure there are exceptions (and this is the place to hear about them /forums/images/graemlins/smile.gif) but those are your basic choices. Like I said, I'd go hydro if $$$ aren't super important.

 

[s1120]

<font color="red"> 4. Any other methods out there that I should know about?

</font>
There are also variations on the different trans. My old JD112 has a gear trans, but it also has a veritable pulley attached to it. With this, you can be in one gear, and vary your speed in that gear with it. Nice setup. Also my Case&#8217;s have a hydraulic drive gear trans. It is two speeds, high, and low, and you vary the speed, and direction, with the hydraulic system. Also a nice setup. Then you have the Greavely setup. It is a planetary transmission. Gear drive, but it is shift on the fly. High, to low, front, to back, no problem. No clutch, no stopping, nothing. I have to wonder why more transmissions are not like that.

 

[Bird]

</font><font color="blue" class="small">( hydraulic drive gear trans )</font>

I sure wouldn't claim to know just how it works, but the Oliver 1755 HydraulShift that I used quite a bit had an 6 forward, 2 reverse, manual transmission, but also had another lever for over/direct/under that you could shift on the fly without using the clutch, etc. in effect giving you 18 forward and 6 reverse gears.

 

[StoneHeartFarm]

Shuttle shift was available on some of the older Simplicity garden tractors. It is tempermental to adjust due to the belt drive, and was not as desireable as high low or vari-drive.

Steve