Are A833 gears synchronized?

[68BabyBlue]

If you make no effort at rev matching or slowing down on a downshift the synchro will have to do more work and require a little more shift effort (for synchro ring friction) to speed up the gear train so the slider teeth, synchro teeth and gear engagement teeth can all be synchronized and the slider can lock them all together. Basically it makes the brass synchro rings work harder which will eventually wear them out a little faster.

I shifted both of these without the clutch. I had the truck transmission rebuilt twice, at about 850,000 miles each time. Shop said they could tell the truck only had one driver. The GTX had no issues. It's all about timing the speed of the counter shaft. Harder on a downshift, because it takes a precise throttle blip to match the gear speeds when completing the shift. Synchros in an 833 are better at accomplishing that than the average driver.

 

[Dave6T4]

I imagine, that after mastering an 18-speed Eaton, it would be easy to no-clutch your way through an A-833. Our VFD had a 2,000 gal. tanker on an International chassis with a 350 h.p Turbo Cummins and 9-speed RoadRanger non-synchro transmission. I eventually got so I could drive it comfortably with only using the clutch to get it rolling. Patience was a virtue. I much preferred the 427 gasser in our GMC pumper, with 5-speed synchro trans and 2-speed rear end. Since this was the truck I drove the most, I got so I could really run it through the gears.
Now, all the fire trucks at my old hall are all automatics.

 

[68BabyBlue]

I imagine, that after mastering an 18-speed Eaton, it would be easy to no-clutch your way through an A-833. Our VFD had a 2,000 gal. tanker on an International chassis with a 350 h.p Turbo Cummins and 9-speed RoadRanger non-synchro transmission. I eventually got so I could drive it comfortably with only using the clutch to get it rolling. Patience was a virtue. I much preferred the 427 gasser in our GMC pumper, with 5-speed synchro trans and 2-speed rear end. Since this was the truck I drove the most, I got so I could really run it through the gears.

Surprisingly, I found it easier to shift the 18 speed, partly because I drove it 1.3 million miles. The other factor was with that with nine forward gears, the truck only had a 500 rpm spread between shifts in the main box. The gear splitting auxiliary box was synchronized. Similar function to the two speed rear. I never got a chance to drive one of the manual 4x4 Spicers back in the day, but I'm sure those twin sticks would have kept a driver busy. I did get to flail a twin stick Mack duplex, and was glad I never had to do it with a load.

 

[sam dupont]

Actually on a downshift the synchro friction is having to drag up in revs, the engine mass through the input, to match the gearbox/driveline speed. And in effect it drags down the car speed some too. Not speed up the drivetrain which I incorrectly said above. Too anxious to get to the Super Bowl.

I can't watch the Super Bowl... I only have one TV and my dog is mesmerized by the Puppy Bowl


In eighth grade, a friend got a 62 Impala SS 327 four-speed. At 13 years old, I had never actually done it myself, but I understood the concept of power shifting from reading about people like Ronnie Sox and Dick Landy; I explained it to my friend Bob.

He picked it up quickly, and soon his parents said they would replace the clutch, but not again. We went for a ride with a couple girls before school one morning. We were going over Skyline Drive, a high, steep ridge that splits the town east and west. Bob power shifted on a slight curve and we went off the road and down the hillside until we got slowed down by trees and became high centered on rocks. His parents didn't like me much and that never changed in the years after.

 

[Bleep Bleep]

If you make no effort at rev matching or slowing down on a downshift the synchro will have to do more work and require a little more shift effort (for synchro ring friction) to speed up the gear train so the slider teeth, synchro teeth and gear engagement teeth can all be synchronized and the slider can lock them all together. Basically it makes the brass synchro rings work harder which will eventually wear them out a little faster.

Thanks! I suspect more miles will make the difference.

 

[Bleep Bleep]

It's all about timing the speed of the counter shaft. Harder on a downshift, because it takes a precise throttle blip to match the gear speeds when completing the shift.

Agreed. Practice, miles, feel. Keeping the next one longer will help too I think.
Btw, would a 23 spline make it relatively easier or difficult than the HD 18 Hemi?

 

[AR67GTX]

In college I had a 70 GTO that had one of the easiest shifting gearboxes I ever experienced. I think the first owner (a women) somehow wore it in. I lived about 3 miles off campus and had some neighborhoods and stop lights on the way. One day I bet myself that I could make it all the way home without touching the clutch until I arrived. It meant some slow rolls through stop signs and timing traffic lights very carefully, keeping the revs fairly low and doing a bit of rev matching along the way but I made. That Muncie would just slide in and out of gears with the lightest touch yet I never experienced it jump out of gear.

 

[old guys rule]

I recall I heard they are not, but just confirming. Thanks!

The old synchros were lousy. New synchros from about I believe 72 and up are much better