So this is the reason why 1st gear is nearly impossible to engage at higher wheelspeeds? Because the force to synchronize at the speed difference is too high?
I watched a lot of videos but this one was short and sweet. Do you know where I can buy just one set of gears, synchro, shaft and shift fork for a simple project/demo like you have?
Thanks for the compliment! I watched your video on the Bronco. Cool channel. When I was rebuilding my transaxle from my 1997 Eagle Talon, I got the idea to show how the synchros work. It was unscripted and I missed one major point, how the synchro sleeve pushes on the teeth of the syncro until the speed is matched and the shaft counter-rotates letting the gear engage. Anyway, if you bought those parts from the dealer, it would probably be as much as a junkyard transmission. Maybe ebay? I know lots of junkyards operate on ebay.
I think I get it, but if the brass synchro gear matches the rigid gear speed through friction, is it just the bevels that allow the slider to move across easily and engage the gear, or do the bevels/teeth have to match perfectly when the speed is matched?
@2:31 The brass synchro ring and the sleeve always rotate at the same speed, but there is some play between the two parts. The sleeve bevel angle matches the bevel angle on the synchro ring so that the sleeve is what is pushing on the synchro until the input shaft speed matches the gear speed. Basically you're pressing the sleeve onto the synchro ring when pushing the stick into gear. The synchro ring in turn will press on the gear's cone and that friction changes the input shaft speed to match the gear speed. When the speed is matched, the input shaft bounces back and counter-rotates. The springs in the clutch disk help with this counter-rotation. The bounce-back allows the teeth to line up and mesh.
No. Some racing trans have large lugs that literally jam into other lugs. It is very aggressive and not really made for the street. They are usually called "dog boxes"
Yes, virtually every modern passenger (and definitely every USDM passenger vehicle) have synchronized forward gears, and a reverse gear, which is usually unsynchronized. Industrial machinery, like tractors and (most) semi trucks, and older buses, have unsynchronized transmissions, or crash boxes. Motorcycles (and most other sequential gearboxes) are almost always unsynchronized, but this is somewhat different in theory compared to an unsynchronized transmission. These are "constant mesh" transmissions with dog clutches in place of synchros, and thus don't require synchros for seamless shifts. Synchros wear though, and many drive with worn synchros. My 1st, 2nd, and 3rd synchros (and clutch) in my 09 Scion tC have been worn to the point that if I don't double clutch, I'll grind gears, or can't get into gear. In effect, it's a non-synchronous transmission with synchros.
With everything disassembled and close up, the point came across to me very clearly. Nice job!
So this is the reason why 1st gear is nearly impossible to engage at higher wheelspeeds? Because the force to synchronize at the speed difference is too high?
Great explanation:)-John in Texas
Okay, I get it now. Thanks.
I watched a lot of videos but this one was short and sweet. Do you know where I can buy just one set of gears, synchro, shaft and shift fork for a simple project/demo like you have?
Thanks for the compliment! I watched your video on the Bronco. Cool channel.
When I was rebuilding my transaxle from my 1997 Eagle Talon, I got the idea to show how the synchros work. It was unscripted and I missed one major point, how the synchro sleeve pushes on the teeth of the syncro until the speed is matched and the shaft counter-rotates letting the gear engage.
Anyway, if you bought those parts from the dealer, it would probably be as much as a junkyard transmission. Maybe ebay? I know lots of junkyards operate on ebay.
I think I get it, but if the brass synchro gear matches the rigid gear speed through friction, is it just the bevels that allow the slider to move across easily and engage the gear, or do the bevels/teeth have to match perfectly when the speed is matched?
@2:31 The brass synchro ring and the sleeve always rotate at the same speed, but there is some play between the two parts. The sleeve bevel angle matches the bevel angle on the synchro ring so that the sleeve is what is pushing on the synchro until the input shaft speed matches the gear speed. Basically you're pressing the sleeve onto the synchro ring when pushing the stick into gear. The synchro ring in turn will press on the gear's cone and that friction changes the input shaft speed to match the gear speed. When the speed is matched, the input shaft bounces back and counter-rotates. The springs in the clutch disk help with this counter-rotation. The bounce-back allows the teeth to line up and mesh.
@@jtandrews3 thanks just as I thought, most animations showed the teeth lining up perfectly and I just couldn’t get my head around that
Thanks looks like older ones in most
All manuals have synchronizers ?
No. Some racing trans have large lugs that literally jam into other lugs. It is very aggressive and not really made for the street. They are usually called "dog boxes"
Yes, virtually every modern passenger (and definitely every USDM passenger vehicle) have synchronized forward gears, and a reverse gear, which is usually unsynchronized.
Industrial machinery, like tractors and (most) semi trucks, and older buses, have unsynchronized transmissions, or crash boxes.
Motorcycles (and most other sequential gearboxes) are almost always unsynchronized, but this is somewhat different in theory compared to an unsynchronized transmission. These are "constant mesh" transmissions with dog clutches in place of synchros, and thus don't require synchros for seamless shifts.
Synchros wear though, and many drive with worn synchros.
My 1st, 2nd, and 3rd synchros (and clutch) in my 09 Scion tC have been worn to the point that if I don't double clutch, I'll grind gears, or can't get into gear. In effect, it's a non-synchronous transmission with synchros.
@@callang9 many thanks