Shifting without syncros

Warui Shujin · 03-27-2008, 07:22 PM

This isn't exactly a track question, but there wasn't a general automotive question area.. So I thought this would be the place to ask.

A while back, I bought a 62 international firetruck. It never had any syncros to begin with, so I can't really do anything about them. I learned how to upshift fairly easily, but I am almost always grinding on the downshifting. Is there anything I can do to improve my record on this? or do I just need to start daily driving it until I have enough practice to rev match all of the gears?

Any tips or hints on how to do so, or learn without killing the transmission would be greatly appreciated. Thanks!

josh18_2k · 03-27-2008, 09:06 PM

you're talking about a diesel truck tranny right?
to downshift, i just push on the stick and rev it until it falls into gear. i've never had a diesel trans grind, and i never use the clutch to shift (up or down).
im pretty sure you pushing on the stick wont mess up the trans. they're built beefy.

Warui Shujin · 03-27-2008, 09:41 PM

Thanks for the help!

It's not a diesel, it's some huge ass gas engine. I don't know the size because I've been to lazy to look it up on the parts list I got with the truck. It does use two starters though. Don't know if that makes a difference.

The tranny does seem fairly tough, and it only has 19000 miles on it.. so it should be pretty unworn. I'll try out your suggested method tomorrow. It'll be fun to take it for a drive anyway.

josh18_2k · 03-28-2008, 09:47 AM

it most likely has strait cut gears, which dont need synchros cuz theyre so much stronger. same stuff in race cars and bikes. just jam it in there, it'll be fine. rev matching will make it smooth, but i seriously doubt your weak human arm can mess that thing up.

jgrewe · 04-12-2008, 08:05 PM

It will just take getting to know what gear you should be aiming for at what road speed. You don't have a jake brake so you don't need to go down through every gear. Just figure out what you need to come out of a corner.

Kentetsu · 04-13-2008, 08:38 PM

What about double clutching? Wasn't that technique intended for use with these types of trannys?

jgrewe · 04-13-2008, 09:40 PM

It helps but its expensive to change a clutch so you try not to do any slipping of it at all. In the big trucks that I've owned(2 Macks, a Sterling and a Peterbilt) we only used the clutches to get rolling. You should be able to get the truck moving without even touching the throttle. After that its all matching revs and only touch the clutch when you stop.

Warui Shujin · 04-14-2008, 10:46 AM

I appreciate the info! And it is fairly easy to get it started without touching the throttle if it's on level ground you can probably pop the clutch and it won't want to die. I've gotten better at the whole shifting thing, now to do it without using the clutch!

03-27-2008, 07:22 PM	#1
Warui Shujin The Newbie Join Date: Mar 2008 iTrader: (0) Posts: 16 Rep Power: 0	Shifting without syncros This isn't exactly a track question, but there wasn't a general automotive question area.. So I thought this would be the place to ask. A while back, I bought a 62 international firetruck. It never had any syncros to begin with, so I can't really do anything about them. I learned how to upshift fairly easily, but I am almost always grinding on the downshifting. Is there anything I can do to improve my record on this? or do I just need to start daily driving it until I have enough practice to rev match all of the gears? Any tips or hints on how to do so, or learn without killing the transmission would be greatly appreciated. Thanks!

03-27-2008, 09:06 PM	#2
josh18_2k Rotary Fanatic Join Date: Feb 2008 Location: Gresham, OR iTrader: (0) Posts: 473 Rep Power: 17	you're talking about a diesel truck tranny right? to downshift, i just push on the stick and rev it until it falls into gear. i've never had a diesel trans grind, and i never use the clutch to shift (up or down). im pretty sure you pushing on the stick wont mess up the trans. they're built beefy. __________________

03-28-2008, 09:47 AM	#4
josh18_2k Rotary Fanatic Join Date: Feb 2008 Location: Gresham, OR iTrader: (0) Posts: 473 Rep Power: 17	it most likely has strait cut gears, which dont need synchros cuz theyre so much stronger. same stuff in race cars and bikes. just jam it in there, it'll be fine. rev matching will make it smooth, but i seriously doubt your weak human arm can mess that thing up. __________________

04-12-2008, 08:05 PM	#5
jgrewe Rotary Fan in Training Join Date: Feb 2008 Location: On the Beach iTrader: (0) Posts: 59 Rep Power: 17	It will just take getting to know what gear you should be aiming for at what road speed. You don't have a jake brake so you don't need to go down through every gear. Just figure out what you need to come out of a corner. __________________ New rat from the sinking ship.

04-13-2008, 09:40 PM	#7
jgrewe Rotary Fan in Training Join Date: Feb 2008 Location: On the Beach iTrader: (0) Posts: 59 Rep Power: 17	It helps but its expensive to change a clutch so you try not to do any slipping of it at all. In the big trucks that I've owned(2 Macks, a Sterling and a Peterbilt) we only used the clutches to get rolling. You should be able to get the truck moving without even touching the throttle. After that its all matching revs and only touch the clutch when you stop. __________________ New rat from the sinking ship.

03-27-2008, 09:41 PM	#3
Warui Shujin The Newbie Join Date: Mar 2008 iTrader: (0) Posts: 16 Rep Power: 0	Thanks for the help! It's not a diesel, it's some huge ass gas engine. I don't know the size because I've been to lazy to look it up on the parts list I got with the truck. It does use two starters though. Don't know if that makes a difference. The tranny does seem fairly tough, and it only has 19000 miles on it.. so it should be pretty unworn. I'll try out your suggested method tomorrow. It'll be fun to take it for a drive anyway.

04-13-2008, 08:38 PM	#6
Kentetsu RCC Contributor Join Date: Feb 2008 Location: Grand Rapids, Michigan iTrader: (1) Posts: 530 Rep Power: 17	What about double clutching? Wasn't that technique intended for use with these types of trannys?

04-14-2008, 10:46 AM	#8
Warui Shujin The Newbie Join Date: Mar 2008 iTrader: (0) Posts: 16 Rep Power: 0	I appreciate the info! And it is fairly easy to get it started without touching the throttle if it's on level ground you can probably pop the clutch and it won't want to die. I've gotten better at the whole shifting thing, now to do it without using the clutch!