What makes a transmission gear non-synchronized?

[65x2]

Someone mind explaining this to me? I have two transmissions that have non synchronized first gears, meaning you have to be at a stop before shifting into them. Im about to do a rebuild on one of them and it got me thinking on how it works.

 

[SonicDTR]

It means it literally does NOT have synchronizers in the transmission. Think of a synchronizer as a "mini clutch" that speeds the gear up to the appropriate speed to prevent grinding and aid smooth shifting.

 

[10splaya22]

It means it literally does NOT have synchronizers in the transmission. Think of a synchronizer as a "mini clutch" that speeds the gear up to the appropriate speed to prevent grinding and aid smooth shifting.

Yea it's just a cone type clutch and they can be made out of different materials depending on the application but look on google because there is lots of good info and diagrams showing how it works.

 

[Robert Francis]

Traditionally, it was thought by those in the auto industry that most people would not shift into first gear while in motion, but only from a standing stop. Therefore it wasn't necessary to have any form of synchronizer for first gear.

 

[LIGHTNING LARRY]

It means it literally does NOT have synchronizers in the transmission. Think of a synchronizer as a "mini clutch" that speeds the gear up to the appropriate speed to prevent grinding and aid smooth shifting.

Or the synchro is broken.

 

[SVT-BansheeMan]

It's good to hear the trans work it's magic. When i go from a high speed to 1st SLOWLY, you can hear the internals speed the hell up before it goes in easy.

 

[EatonEggbeater]

Going into first while still moving is where "double clutching (like you should)" would come into play.

 

[roy_1031]

Going into first while still moving is where "double clutching (like you should)" would come into play.

Can't you just bring the RPMs up before shifting into first instead of this double clutching business?

 

[EatonEggbeater]

Can't you just bring the RPMs up before shifting into first instead of this double clutching business?

That's what you're doing.

If you tried to go from 2'nd to 1'st gear, the clutch and input assembly are spinning too slowly for the gears to engage and they will grind until the speeds are equal.

You need to shift to neutral, let the clutch out, spin up the motor/clutch/input assembly, clutch in, get 1'st gear, and let clutch out slowly. Keep the motor revved so the engine speed and drivetrain speed match.

Synchromesh transmissions are pretty cool, once you see how they work you'll understand.

 

[Riddla]

My transmission will grind going into first at a complete stop unless i go into second first. Sometimes i have to double clutch since first will be locked out.

 

[roy_1031]

That's what you're doing.

If you tried to go from 2'nd to 1'st gear, the clutch and input assembly are spinning too slowly for the gears to engage and they will grind until the speeds are equal.

You need to shift to neutral, let the clutch out, spin up the motor/clutch/input assembly, clutch in, get 1'st gear, and let clutch out slowly. Keep the motor revved so the engine speed and drivetrain speed match.

Synchromesh transmissions are pretty cool, once you see how they work you'll understand.

I do all that minus letting the clutch out and grabbing it again. Just blip the throttle up and engage the shifter into first and it goes right in for me without grinding and sticking.