Transmission assembly problem

openroad · Apr 6, 2017

Whatever I'm doing wrong, I'm getting good at it.
I'm pretty sure the quadrant is in Neutral, looks just like the picture in the manual. Once assembled I can run thru the gears 1st thru 4th, then it jams downshifting into 3rd and won't move until I take it apart...again. What am I not seeing here?

Jammed in 3rd, but will go back to 4th

pantah_good · Apr 6, 2017

Are you turning or rocking the shafts when shifting?

dynodave · Apr 6, 2017

Your pix never show the 4th gear alignment, which is how I set mine...by the book... and I never have trouble.
I observe your quadrant/cam plate is probably off by one tooth. High by one tooth if it's in 3rd detent...

Dave who owns 20 AMC & 3 Norton gearboxes :mrgreen:

acadian · Apr 6, 2017

Had the same problem with my GB rebuild, issue turned out to be in the outer cover, specifically the hairpin spring on the gearchange mechanism was rubbing. You can isolate the problem by assembling the inner cover, and seeing if you can get up and down through the gears with a big flat screwdriver in the quadrant operating lever

openroad · Apr 6, 2017

Ok, my bad, Should have put this up from the start..
The pawl and quadrant haven't been removed since 1974, and was shifting correctly when I began this. I was just replacing bearings and shaft bushes.
The last picture of the inside cover is showing it's in third gear, I haven't gotten any further than this step, it goes up to fourth and down to third where it jams, and I disassemble again.
I was turning the the main shaft with a clutch center to check shifting, could simply doing that cause a jamb while levering the lever??
Mick says put in neutral, Old Brits mentions putting it in third gear for shifter fork placement. Maybe that's that's where I'm messing up...fork placement in quadrant?
Fourth gear mainshaft I just popped in, guess I can nudge it out again and start over , but the lay shaft I wouldn't want to pull out again, using Mick's ball bearing, it's in there now.
thanks for the any help!

L.A.B. · Apr 7, 2017

openroad said:
The last picture of the inside cover is showing it's in third gear, I haven't gotten any further than this step, it goes up to fourth and down to third where it jams, and I disassemble again.
I was turning the the main shaft with a clutch center to check shifting, could simply doing that cause a jamb while levering the lever??

No, it should help the gears to select, but you may also need to rotate the sleeve gear as well.

openroad said:
Mick says put in neutral, Old Brits mentions putting it in third gear for shifter fork placement. Maybe that's that's where I'm messing up...fork placement in quadrant?

As long as the selector fork goes in, then it shouldn't matter.

openroad said:
Fourth gear mainshaft I just popped in, guess I can nudge it out again and start over , but the lay shaft I wouldn't want to pull out again, using Mick's ball bearing, it's in there now.

You shouldn't have to remove the layshaft to reposition/retime the camplate and quadrant (which I'm not sure it actually needs).
One observation from your photos although I could be wrong is there doesn't seem to be any oil on the parts and that won't be helping the gear selection.

dynodave · Apr 7, 2017

openroad said:
The pawl and quadrant haven't been removed since 1974, and was shifting correctly when I began this.

The cam plate and quadrant do NOT have to ever be removed to effect good or bad reorientation. Proper re synchronization is done at the bottom of the quadrant stroke where they become unmeshed.
As I stated, proper orientation is best checked by putting the cam plate in 4th and observing the top line of the quadrant where the knuckle pin roller sits. Mick Hemming video shows it... but blows by it rather quickly. If that is not done then it is all a crap shoot after that. Do you feel lucky :roll:

I failed to understand why all norton gearboxes left the factory in functioning order but he felt a need to "chamfer" the top and bottom of the quadrant slot. :?:

openroad · Apr 7, 2017

I'll start over again.
I did oil everything up as I assembled the first time....LOL...must have worn it off redoing it....

Deets55 · Apr 7, 2017

openroad said:
I'll start over again.
I did oil everything up as I assembled the first time....LOL...must have worn it off redoing it....

Don't forget to get some lube on the fork retaining rod, when that is dry there is the possibly it can bind a little.

ILLF8ED · Apr 8, 2017

I just got my gearbox back together and it also was having a similar problem. I had 3rd gear mainshaft in backward so the with the inner case off it would push the entire mainshaft gear cluster to the timing side. Work slowly when assembling and if any binding at all go backward and recheck. My shifts nicely this morning and have most of the drive train done.

openroad · Apr 8, 2017

Took it all apart down to the bearings, followed shop manual again, kept it oiled up, installed inner cover and still had some sticking, would take a lot of rocking of sleeve gear and mainshaft to get it thru the gears, made a long video of my thrashing around. Walked away from it and turned on some Bob Seger, just for the heck of it checked it once more and it worked like a charm. Well...Bob Seger. And one of the barn cats walked in....so it's a combination I can't rely on all the time.

[video]https://youtu.be/3Vj71vaD1sc[/video]

Before I button this thing up, think I'm good to go? I mean it looks slick now but minutes before it took a lot of rocking.

"I just got my gearbox back together and it also was having a similar problem. I had 3rd gear mainshaft in backward so the with the inner case off it would push the entire mainshaft gear cluster to the timing side. Work slowly when assembling and if any binding at all go backward and recheck. My shifts nicely this morning and have most of the drive train done."

Could you put the inner cover on with the gear reversed?

openroad · Apr 8, 2017

dynodave said:
openroad said:

The pawl and quadrant haven't been removed since 1974, and was shifting correctly when I began this.

Click to expand...

The cam plate and quadrant do NOT have to ever be removed to effect good or bad reorientation. Proper re synchronization is done at the bottom of the quadrant stroke where they become unmeshed.
As I stated, proper orientation is best checked by putting the cam plate in 4th and observing the top line of the quadrant where the knuckle pin roller sits. Mick Hemming video shows it... but blows by it rather quickly. If that is not done then it is all a crap shoot after that. Do you feel lucky :roll:

I failed to understand why all norton gearboxes left the factory in functioning order but he felt a need to "chamfer" the top and bottom of the quadrant slot. :?:

Look right?

L.A.B. · Apr 9, 2017

openroad said:
Took it all apart down to the bearings, followed shop manual again, kept it oiled up, installed inner cover and still had some sticking, would take a lot of rocking of sleeve gear and mainshaft to get it thru the gears, made a long video of my thrashing around. Walked away from it and turned on some Bob Seger, just for the heck of it checked it once more and it worked like a charm. Well...Bob Seger. And one of the barn cats walked in....so it's a combination I can't rely on all the time.
Before I button this thing up, think I'm good to go? I mean it looks slick now but minutes before it took a lot of rocking.

You probably aren't experiencing anything out of the ordinary, when it finally worked as shown in your video, was most likely because all four sets of gear dogs happened to come to rest where they would engage and that is why rotating the shafts helps gear selection. If you watch the Mick Hemmings video from 55.30 (and 1:07:40) he turns the mainshaft and the sleeve gear (with the sprocket) as he checks the gear selection.

dynodave · Apr 9, 2017

openroad
Yes your alignment looks good.
To be off by one tooth either way can put the knuckle alignment to the top or bottom of the top stud. It is not much.
As previously stated a dog transmission such as our motorcycles or formula race car gearboxes must have motion to allow gear selection.
This is a basic principle that I teach at my tech session and if not emphasized is a disservice to the students.

openroad · Apr 9, 2017

Sounds great! thanks!

I have to go back in anyway, while straightening up the work bench for the night I saw this........

pantah_good · Apr 9, 2017

What, the inner cover gasket? Bah, I hear they're overrated.

openroad · Apr 10, 2017

dynodave said:
openroad
Yes your alignment looks good.
To be off by one tooth either way can put the knuckle alignment to the top or bottom of the top stud. It is not much.
As previously stated a dog transmission such as our motorcycles or formula race car gearboxes must have motion to allow gear selection.
This is a basic principle that I teach at my tech session and if not emphasized is a disservice to the students.

somehow, I missed that fact along the the way, even with videos and manuals. I bet I put that dang thing together correctly every time but thought I had botched it!

openroad · Apr 10, 2017

pantah_good said:
What, the inner cover gasket? Bah, I hear they're overrated.

dynodave · Apr 10, 2017

openroad said:
dynodave said:

openroad
Yes your alignment looks good.
To be off by one tooth either way can put the knuckle alignment to the top or bottom of the top stud. It is not much.
As previously stated a dog transmission such as our motorcycles or formula race car gearboxes must have motion to allow gear selection.
This is a basic principle that I teach at my tech session and if not emphasized is a disservice to the students.

Click to expand...

somehow, I missed that fact along the the way, even with videos and manuals. I bet I put that dang thing together correctly every time but thought I had botched it!

Out of curiosity, I recently borrowed and watched the NOC/Mick H gearbox video. He mentions the turning of the shafts to shift but not don't think he specifically calls them out to be a dog transmission.
The norton shop manual does not say it at all. Most shop manuals are NOT written for beginners. As a professionally educated and trained mechanic this should have been covered in the first or second semester. The shop manuals are supposed to give you the speedy highlights and problem avoidance specifics.
In the last month I studied the AMC gearboxes and learned way more than I have seen or heard over the last 25 years from any and all sources. I have 5 gearboxes in work progress at the moment. I learned one thing/tip from the video and disagree strongly with two things he advocated .

auldblue · Apr 10, 2017

I have not serviced or rebuilt a gearbox for a year or two but I watched the NOC gear box video with mick Hemmings and I would think he has built a few in his time with no song and dance with all combinations of ratios and speeds. It was him I bought my new shell from when I did my 69 box, I also use the layshaft bearing that he recommends , it was all quite straight forward stuff and my boxes all work, but it's not so easy figuring out wheather some bits are past their best or out of line, shape etc that is where the knowledge and experience is invaluable . I use the dynodave pushrod seal to keep my gear oil in the box and off the clutch on both my commandos , no drag, no fuss.

Jg

Transmission assembly problem

openroad

pantah_good

dynodave

acadian

openroad

L.A.B.

Moderator

dynodave

openroad

Deets55

ILLF8ED

openroad

openroad

L.A.B.

Moderator

dynodave

openroad

pantah_good

openroad

openroad

dynodave

auldblue

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