What does it mean when you have a "synchronized" transmission?

[Jerry1]

Ok, maybe it's a stupid question, but before I mess anything up I need some clarification.

I've got a JD 1070 with the normal clutch and floor gear shift. It's got three gear ranges, with six forward and one reverse gear in each range (except no reverse in the highest range).

I understand that being a synchronized transmission, I can shift between gears within a range while moving but have to stop and use the clutch to shift between ranges. But do I have to use the clutch while moving to switch between gears in the same range? And what about shifting between a forward gear and reverse in the same range - do I need to use the clutch? If I have to use the clutch for any change of gearing, what does the synrchronizing really do for me - just make it possible for me to change gears without fully stopping?

Thanks for clearing this up for me.

Jerry

 

[k0ua]

Well I am not the gear "mac-daddy" around here but I believe what you described is exactly right. it allows you to shift gears within a range while on the move, but still need to clutch just like a car. Lets see what some of the more experienced "gearheads" have to say. I am a big fan of the HST transmission myself. The gear tractors I have owned were not synchro.

James K0UA

 

[Tx Jim]

Ditto what k0ua stated

 

[RoyJackson]

Ok, maybe it's a stupid question, but before I mess anything up I need some clarification.

I've got a JD 1070 with the normal clutch and floor gear shift. It's got three gear ranges, with six forward and one reverse gear in each range (except no reverse in the highest range).

I understand that being a synchronized transmission, I can shift between gears within a range while moving but have to stop and use the clutch to shift between ranges. But do I have to use the clutch while moving to switch between gears in the same range? And what about shifting between a forward gear and reverse in the same range - do I need to use the clutch? If I have to use the clutch for any change of gearing, what does the synchronizing really do for me - just make it possible for me to change gears without fully stopping?

Thanks for clearing this up for me.

Jerry

You do need to use the clutch when shifting gears, but you do not need to stop the tractor (as you would with a non-synchro (collar shift) transmission.
As you wrote, you do need to stop when changing ranges.

I have a sync-reverser tranny in my Deere 4400...works similar to your gear tranny...main difference is reverse. You have reverse gears (three speed, one per range)...the reverser has 12 forward, 12 reverse.
My previous Deeres (a 670 and a 790) were both collar shift and I had to stop to change gears.

 

[RalphVa]

Doubt any tractors have synchronized transmissions. Such on a car or pickup means you can shift on the go with or without the clutch while going the same direction. The clutch just takes the tension off the gears and makes it easy. You can shift without the clutch if you do it by manipulating the fuel pedal to release tension on the gears and/or to synchronize the engine shaft rpm with the gearbox shaft rpm. I've done it many times in a car or pickup, going both up or down in the gears.

To go to reverse, you have to stop and use the clutch. If you have vehicle with multiple ranges, you often have to stop to change ranges. On a tractor, some will allow range changes on the fly. Others won't.

Ralph

 

[RoyJackson]

Doubt any tractors have synchronized transmissions. Such on a car or pickup means you can shift on the go with or without the clutch while going the same direction.

Ralph

I've known of guys who shifted gears (in trucks) without using the clutch...not a good practice though and it's easy to tear a clutch up if you miss a gear.

 

[RalphVa]

Roy, you cannot tear a clutch up if you're not using it. As long as you release the tension on the gears when shifting, you're doing exactly the same thing that the clutch is doing. Main thing is to get some synchronization between engine shaft and next gear shaft. You can do this by blipping the throttle in neutral, just like you'd do in double clutching, like most race car drivers used to do. Now, many of them "synch" the engine speed to match its shaft speed to the next gear's. I learned double clutching on an old 1953 Plymouth with no synchro on 1st gear. I could double clutch and go down from 2nd to 1st gear. Didn't try it without the clutch back in those days. That old flat head 6 engine didn't rev much. Of course, you could just max out in a gear and hold it there without fear of warping a valve against a piston, as they were off to the side. Never did blow an engine.

Ralph

Ralph

 

[RoyJackson]

Roy, you cannot tear a clutch up if you're not using it. As long as you release the tension on the gears when shifting, you're doing exactly the same thing that the clutch is doing. Main thing is to get some synchronization between engine shaft and next gear shaft. You can do this by blipping the throttle in neutral, just like you'd do in double clutching, like most race car drivers used to do. Now, many of them "synch" the engine speed to match its shaft speed to the next gear's. I learned double clutching on an old 1953 Plymouth with no synchro on 1st gear. I could double clutch and go down from 2nd to 1st gear. Didn't try it without the clutch back in those days. That old flat head 6 engine didn't rev much. Of course, you could just max out in a gear and hold it there without fear of warping a valve against a piston, as they were off to the side. Never did blow an engine.

Ralph

Ralph

I've done double clutching (early 50's International pick up, in my case), so I know the process. I know some truckers (18 wheelers) who shift without the clutch.
But, as I wrote, it can be tough on the gears if you don't do it smoothly, at the right RPM and quickly. Not worth tearing a transmission up, IMHO.

 

[creekbend]

I've known of guys who shifted gears (in trucks) without using the clutch...not a good practice though and it's easy to tear a clutch up if you miss a gear.

I had a 72 VW Super Beetle that I could go through all 4 gears without ever using the Clutch.

 

[farmgirl19]

I had a '59 VW Beetle (No I did not buy it new!). First gear was not sync'd, and you had to be to a complete stop to get it into 1st. I learned how to do a lot only downshifting to 2nd!