Need A833 advice

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Jim64

Jim64

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I have an a-body A833 with a Passon OD gearset. I just got it on the road last week, with basically everything from the radiator to the transmission replaced or rebuilt.

I drove the car (64 Barracuda) a couple of miles, and then into the garage. At some point I decided to push it forward for clearance, and realized I could not push it forward (in neutral with e-brake off), but I could push it backwards.

I finally tracked it down - it's the first-gear synchro ring. With the side cover off, and the driveshaft disconnected, when I try to rotate the driveshaft 'forward', it sticks, but if I separate the synchro ring from first gear, it rotates properly. If I keep rotating it, eventually the synchro ring will slip into the gear, and stick again. If I rotate the driveshaft 'backwards', it never sticks, and rotates freely.

I have no idea why, and no idea why it only sticks in one direction!

Any ideas? Should I just drive it, and figure the mass of the car and the power of the engine will force the syncro ring to slip, or will I break something if I try?
 
I don't really know but my first inclination might be improper gear oil.
Other more knowledgeable guys will chime in for sure.
A call to Jamie or Brewer's might help but they were both st the Mopar Nats this weekend so best to wait a couple days.
 
Jim64 said:
I have an a-body A833 with a Passon OD gearset. I just got it on the road last week, with basically everything from the radiator to the transmission replaced or rebuilt.

I drove the car (64 Barracuda) a couple of miles, and then into the garage. At some point I decided to push it forward for clearance, and realized I could not push it forward (in neutral with e-brake off), but I could push it backwards.

I finally tracked it down - it's the first-gear synchro ring. With the side cover off, and the driveshaft disconnected, when I try to rotate the driveshaft 'forward', it sticks, but if I separate the synchro ring from first gear, it rotates properly. If I keep rotating it, eventually the synchro ring will slip into the gear, and stick again. If I rotate the driveshaft 'backwards', it never sticks, and rotates freely.

I have no idea why, and no idea why it only sticks in one direction!

Any ideas? Should I just drive it, and figure the mass of the car and the power of the engine will force the syncro ring to slip, or will I break something if I try?
Click to expand...

Call Jamie Passon.
 
It's his gear set. I tend to take all info and make up my mind from what makes the most sense to me. I also tend to give the benefit of doubt in most cases.
 
If I understand you right
this gearset is a regular A833 gearset.
Is it used or new?

But before you go any further;
remove the driveshaft from the rear end.
If you have a spare rear yoke, drop the driveshaft and stick the yoke in there. If you don't have a spare, block the driveshaft up in a cradle so it has to stay there.
Now repeat your test.

Here's the why of it;
What you are describing is in all likelyhood originating in the rear brakes, especially if they are drums. Drum brakes are self-energizing. And in reverse, the shoes like to drag on the drums. If they start dragging, they will rotate slightly and then jam up.
Therefore;
A second option instead of removing the driveshaft, is to remove the wheels and drums.

If it should happen that this does not cure your problem, then I can tell you what I think could be wrong with that synchro; I have built hundreds of manual transmissions possibly thousands of them. But first, you need to prove that it ain't the brakes.
 
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AJ/FormS said:
If I understand you right
this gearset is a regular A833 gearset.
Is it used or new?

But before you go any further;
remove the driveshaft from the rear end.
If you have a spare rear yoke, drop the driveshaft and stick the yoke in there. If you don't have a spare, block the driveshaft up in a cradle so it has to stay there.
Now repeat your test.

Here's the why of it;
What you are describing is in all likelyhood originating in the rear brakes, especially if they are drums. Drum brakes are self-energizing. And in reverse, the shoes like to drag on the drums. If they start dragging, they will rotate slightly and then jam up.
Therefore;
A second option instead of removing the driveshaft, is to remove the wheels and drums.

If it should happen that this does not cure your problem, then I can tell you what I think could be wrong with that synchro; I have built hundreds of manual transmissions possibly thousands of them. But first, you need to prove that it ain't the brakes.
Click to expand...
Oh yeah - I did all that. Was hoping for brakes; no luck. Then eliminated rear axle. Disconnected the driveshaft at the rear, suspended it on a piece of rebar between the exhaust pipe. It's definitely first-gear synchro. I can watch the synchro move over towards the gear, and then lock up. (But only one direction!!!) I can free it by prying the synchro away from the gear with a screwdriver, but it walks back.

Other than fixing it, I'm now trying to do the math in my head. In first gear, it wouldn't matter. But in 2/3/4, is the first gear rotating faster or slower than the mainshaft? If faster, I should be OK, right?

I'll see if I can upload a video...
 
Was there a problem starting, running, driving???. Or just pushing around in the garage??..
 
Hard to say! It was the first day on the road in about 10 months. The engine is only tuned enough to get running, and it was lacking power on the drive, so it's possible the trans was fighting me. Not sure on that yet. Starts OK.
 
Jim64 said:
Hard to say! It was the first day on the road in about 10 months. The engine is only tuned enough to get running, and it was lacking power on the drive, so it's possible the trans was fighting me. Not sure on that yet. Starts OK.
Click to expand...
But you're saying the trans wasn't making any loud whining noises or popping out of gear or shifting improperly this is just something you discovered while pushing it?
I'm starting to think that you may be overthinking it...
 
Don't overlook brass synchros, sometimes a cracked one will look normal when inspected but spread a little when pressure is applied.
 
j par said:
But you're saying the trans wasn't making any loud whining noises or popping out of gear or shifting improperly this is just something you discovered while pushing it?
I'm starting to think that you may be overthinking it...
Click to expand...
You might be right! No troubles otherwise (that I can tell from a 1-mile drive.)
 
The trans might have to come apart.
but before you go that far;
Here's my opinion;
Assuming this is a regular A833; and with the cover off, and the forks removed,
I think that there can be only two possible reasons for this situation;
1) there is something pressuring the brass to move onto the brake cone or
2) the brake cone is grabbing the brass and tugging it in.
My money is on the first.
Therefore, here is the diagnostic;
Push the synchro sleeve away from the brass ring as far as it will go. This will cause the struts to pop up, out of the over-shifted slider.
Now rotate the mainshaft, and make sure every strut has popped up. If you find one that has not, figure out the why of it, and fix it.
There is an energizer spring inside the hub that is supposed to apply pressure to those struts. It's just a length of metal-wire, formed into a circle to be a ring, and has a hook on the end. Make sure the hook is indexed into/inside the back of one of the struts, which are hollow to receive it. And all the other struts are sitting on top of the wire. Each strut has a formed edge that is supposed to keep the wire from popping out; make sure that yours are not broken off.
In the car this is a PITA to do.
Once you are confident that the spring is properly so indexed, it's time to pull the slider back over the struts; but first, each strut has to be individually pushed back into the slider. But as you are doing that, the slider has to have a lil pressure applied to it, so it cannot run away; more PITA-uzzury.
Once the slider is centered back in Neutral, repeat your test.
If it does it again, or if you did not find a spring out of place;
then move the slider the other way, and check the Second gear spring and locking edges in the same way. Then repeat the test.

But if you didn't find anything amiss, then it has to be the second reason, and to cure that, the trans will have to come apart, and the brake cone smoothed.
----------------
When I build one of these transmissions, I chuck each gear in a lathe, and polish the brake cones. This is just swiping the spinning cone, two or three times, with a lathe-file that has a length of emery-cloth folded over it.
First I rub off, the step that sometimes forms at the base. Then I just deglaze the rest, and make sure that it is flat. Finally, I put a screw on the face by running the emery from the base to the top and off the edge. The idea here is to bias the cone to grab the brass, as the slider puts pressure on it during the shift process. I bias ALL gears, except first, in the upshift direction, and so the lathe has to be spinning in reverse direction for some of them. I bias First gear for downshifting, but not aggressively, because it makes it too difficult to in-shift when stopped.
Now, if Passon did the same, but in the wrong direction, or more aggressively............ it doesn't take much pressure for the brass to climb the screw and grab it ........... My own A833 shifts like lightning.

But again; My money is on a spring pressuring the brass, which might just be out of place, or one of the struts is damaged.

Good luck
 
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AJ/FormS said:
The trans might have to come apart.
but before you go that far;
Here's my opinion;......
Good luck
Click to expand...

AJ - thank you! I do appreciate the thoroughly described process, and I think you're onto it. I'm hoping for plan A, but thinking it might be plan B.
I've already over-shifted the 1-2 slider towards 2nd gear, and of course without the clutch released, I can't rotate the gears at all. I guess I'll need a helper, or a stick just the right size! And yes, it is a huge pain to get the slider back in the neutral position. I was able to get my fingers on the key in front and the key up over the top-side of the gears, but needed a large allen wrench to shove the third one in while I pushed the slider back. (Somehow I got it done while being able to see NOTHING because my hands were in the way!)

I was pretty careful during the assembly process, but it never occurred to me to treat the gears' brake cones. Makes perfect sense the way you described it. Of course I don't have a lathe, so I'll need to do these by hand. Based on this bit of knowledge, and the behavior of the trans, it seems like the first gear cone might be biased towards upshifting. (Here I am, trying to do transmission math in my head again!)
 
Jim64 said:
AJ - thank you! I do appreciate the thoroughly described process, and I think you're onto it. I'm hoping for plan A, but thinking it might be plan B.
I've already over-shifted the 1-2 slider towards 2nd gear, and of course without the clutch released, I can't rotate the gears at all. I guess I'll need a helper, or a stick just the right size! And yes, it is a huge pain to get the slider back in the neutral position. I was able to get my fingers on the key in front and the key up over the top-side of the gears, but needed a large allen wrench to shove the third one in while I pushed the slider back. (Somehow I got it done while being able to see NOTHING because my hands were in the way!)

I was pretty careful during the assembly process, but it never occurred to me to treat the gears' brake cones. Makes perfect sense the way you described it. Of course I don't have a lathe, so I'll need to do these by hand. Based on this bit of knowledge, and the behavior of the trans, it seems like the first gear cone might be biased towards upshifting. (Here I am, trying to do transmission math in my head again!)
Click to expand...
Personally I have AJ on ignore LOL he planted all that huckle buckle in my brain when I was rebuilding my transmission about out of around synchros blah blah blah...
I went ahead and rebuilt mine from a book I bought at the store from a pro who does them with pictures. As a matter of fact I have one apart for a customer right now it's a t10 Chevy transmission but a lot of them are quite similar.. anyways I was like you and very careful and put everything together correctly and since then have pulled the front tire off the ground at the drag strip and no problems whatsoever... Honestly I think you should just put the cover back on it and drive the car and see if anything happens them damn things are near bulletproof... My opinion if something would have happened it would have...
Again I put it back together stop the paranoia and drive it a little bit...
 
I'm not advocating for you to put AJ on ignore just so you know... Let me guess his post was about eight pages long.. LOL...
Here's a picture from a couple hours ago..
PXL_20210816_190621841.jpg
 
One other thing I did have a problem when I rebuilt it that had something to do with reverse. And it was Rusty rat rod who came on and told me to loosen the cover and push up on the cover really hard and tighten it back down. It totally solved my not going into reverse issue...
Kind of weird but I heard it again since then as well something you might try when you put the cover back on but obviously nothing to do with what you're talking about right now..
 
j par said:
One other thing I did have a problem when I rebuilt it that had something to do with reverse. And it was Rusty rat rod who came on and told me to loosen the cover and push up on the cover really hard and tighten it back down. It totally solved my not going into reverse issue...
Kind of weird but I heard it again since then as well something you might try when you put the cover back on but obviously nothing to do with what you're talking about right now..
Click to expand...

Thanks. This is the third A833, and the other two were bulletproof, so I was not expecting this. I guess I know that SOMETHING is going to give, so I'm weighing the odds. It is always good to hear as much info as possible, so that I can make an informed decision.
 
Jim64 said:
Of course I don't have a lathe, so I'll need to do these by hand.
Click to expand...
This cannot/must not, be done by hand. The cone is pretty hard but it has to be a perfect cone when yur done, or the brass will not work right.
The bore in the first gear is too small to fit in most lathes. I had to make a tool to mount the gear into, and then chuck the tool. And I have to spin first gear slower compared to the others, to be sure the brake cone gets a proper swipe.
 
IMO; yur doing the right thing.
I would be chasing the problem too.
There is no way on God's green Earth , that I would just drive it; IMO that is insanity.
My record for dropping that trans, and the GVod behind it, and the dual 3" pipes, plus the shifter, etc., is;
are you ready for it?
Seventeen minutes on a drive on hoist, with air tools; I have witnesses .
Popping the loaded mainshaft out is about a minute more.

BTW
popping the struts back in, not knowing if the anchor tab on the energizer spring is properly indexed, is a recipe for trouble, as the energizer spring is then free to rotate inside the hub. If that happens, the loss of one strut will cause shifting difficulties.

I just thought of a possible third reason for your trans to be malfunctioning. The M/S rear bearing is specific to this trans. It is not likely that any bearing store will keep stock on the shelf. It is special as to the center-hole, and as to it's depth.
But it is a bit of a PITA to install the retaining snap-ring. What-if the builder screwed up?
If the snap ring was not correctly fully installed, and eventually popped out, then the M/S bearing would be able to walk back and forth in it's bore.
As it happens, Chrysler made those gears helically cut, so then, the spinning input gear drives the M/S gears in one direction when going forward, and in the opposite direction when the wheels are doing the driving.
Hmmmmmmmmmmmmmm
It's just a thought........
 
AJ/FormS said:
IMO; yur doing the right thing.
....
Click to expand...

That's pretty fast! I've got a lift, but no air tools and no trannie jack. It will take me longer, even without the GV overdrive.

I'm the builder. The M/S bearing is a standard 307, and on this trans it's held on the M/S with a snug snap ring (and I installed it myself), and on the front side is held in place with the the ring on the inside bore of the tailhousing. I don't see any room for movement there, especially on the M/S itself.

The synchro clusters were assembled properly; I was very careful and took my time. Of course, something could have gone wrong since then, but I doubt it.

I might be mis-reading your last sentence, but If I'm not, I believe it to be wrong. As long as the engine is running and the clutch is engaged, all of the gears will be spinning in a constant direction, whether the car is moving forwards, backwards, or stopped in neutral. The input gear and the M/S gears will all turn in the same direction as the engine, and the counter-shaft will spin in the opposite direction.

So that takes me back to my previous question - when in 2nd, 3rd, and 4th gears, will the M/S be spinning faster than first gear is, or slower? If the M/S is spinning slower, then my trans will be good as-is. If not, I think my only option is to pull it apart...
 
Jim64 said:
So that takes me back to my previous question - when in 2nd, 3rd, and 4th gears, will the M/S be spinning faster than first gear is, or slower? If the M/S is spinning slower, then my trans will be good as-is. If not, I think my only option is to pull it apart...
Click to expand...

The higher the gear the faster the M/S will be spinning. Think about it this way: engine is turning 6000 rpm - will the car be faster in 4th or 1st? The M/S rpm is directly related to speed of the car (M/S rpm divided by rear end ratio = tire rpm. Tire rpm times tire circumference (in miles) times 60 = mph).

6000 rpm in 4th gear (1:1 direct drive): 6000/3.55 = 1690 rpm for the tire. Tire circumference (e.g. 26" tire): 81.7 times 1690 (tire rpm) = 138,073 inches per minute = 8,284,380 inches per hour = 130.74 mph (1 mile = 63,360 inches).

Now do the same thing in 1st gear: just divide everything by the first gear ratio e.g. 2.66 - you see that the M/S has to spin slower.

Every gear is spinning faster than the previous gear - 2nd is spinning faster than 1st, 3rd faster than 2nd,... so the M/S is either the same speed as first speed gear (when locked to the M/S) or it will always turn faster than 1st speed gear as soon any other gear than first is selected. Does this make sense?

But don't worry about that - it is physically impossible to assemble the transmission in such a way that the M/S would be slower than first gear. There is only one way the speed gears and cluster gear go together.

You could try to squirt some thicker oil on the first gear cone and repeat your test. If the cone is too grabby the oil would take care of that and it shouldn't lock up. If it still locks up then something is pushing the brass onto the cone.
 
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