3rd gear knock updated 5/28

Looks like a lot of slack before the pedal moves the TO. It should be like Tom said yesterday.

I would surprised if that cause the noise but the slop should be taken care of.
 
I am not certain, but I just saw the latest video, and it looks to me like a transmission issue. The rattle seems perfct for a gear to gear contact and the E-brake is vibrating as a tell. This is, a rebuilt trans, that is noisy. I would yank it and either go through it personaly, or give it back to the rebuilder. The secong and high gear sliding gear, or the low and reverse gear, might be out of position when third is selected, causing the rattle on another gear on the cluster. Perhaps the front bearing on the main drive gear has a sag? In any event I would pull the tower and check for shiny teeth on every gear. It's only bolts away from a look and nothing to lose.
Good luck, and let us know what you find as the video really get the curiousity going!
 
interesting sound - (first video) - tat-tat-tat-tat until the throwout hub/bearing contacts the fingers (clutch pedal pushed in.) As soon as the throwout is on the fingers, the sound ends.

The transmission gears are still moving at that point (they don't instantaneously come to a complete halt) and the only thing that is 'removed' from the mix is the pressure plate/clutch/flywheel interface.


  • Does the sound happen in neutral?

  • With the clutch released and the engine RPM up, does jiggling the shifter slightly (toward the four quadrants) cause a similar noise?

  • What about reverse? Can you hear the sound?
  • Have you used a stethoscope to try to isolate the noise?
  • Maybe a broken/weak spring on clutch/pressure plate?
  • Could it be an alignment issue - maybe a cracked flywheel housing allowing some misalignment? I'd think that would make the sound throughout all the gears.
I'd lean toward pulling the transmission / clutch housing and checking from the crankshaft to the pressure plate and all points in-between.
 
Hi Kevin,

1. Clutch Play: Difficult to see from a bird's eye view; but appears clutch play may be a bit excessive -- should be 1" -- if excessive, could cause gear grinding while shifting.

2. To verify, lay ruler flat across brake pedal, extending over the clutch pedal. The difference in dimensions from the backside of the flat ruler to the top of the clutch pedal should measure 1" when checking clutch pedal movement; i.e., at 0" from when the clutch pedal is all the way up, to 1" when the clutch pedal is depressed enough to just begin to actually "move" the throwout bearing forward.

3. Noise Diagnosis -- "Wherever" it Originates:

A. If one looks at Volume 1, page 32, of How to Restore Your Model A; and/or page 48, Paul Moller's Volume 2 Green Handbook, one sees a cut away view of a Model A transmission in 1st, 2nd, 3rd, & reverse, (also view of neutral in the Mr. Moller's Handbook).

B. Interesting to mechanically compare & imagine all gear positions, especially in "only noisy" 3rd gear.

C. Even more interesting is to imagine what happens when the "noise stops" when the clutch pedal is depressed & the throwout bearing moves forward, where at this point, the transmission gears are being rotated by a force from the rotating "rear drive shaft".

D. Next, the "noise resumes" when the throwout bearing is being pulled back with a spring when the clutch pops up. At this point, the transmission gears are being rotated by a force from the "front", i.e., the "engine".

E. In addition this difference furthermore involves pressure on one side of the gear teeth with clutch in, & pressure on the opposite side of the gear teeth with clutch out.

No doubt it could be one of several mechanical things that requires verification.

Definitely not a solution, but food for thought while hoping this helps whoever reviews this matter further.
 
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Kevin,
Slim chance here but I had a noise like yours last year in my touring car. The transmission main drive gear and the main drive gear snap ring were worn. The snap ring would not hold (secure) the main drive gear in location and it moved back slightly. This condition coupled with excessive wear on the input stub to the pilot bearing created a noise in third gear like you have. Were both or either of these parts replaced when the transmission was rebuilt?
I originally thought it was a clutch problem so I pulled my engine to find the condition but I think I would have seen it if I had taken the shift tower off and noted the position of the main drive gear. You will not be able to see if the snap ring is in position as this part is blocked from view by the main drive gear bearing retainer. See if you have excessive endplay in the main drive gear by trying to move it forward or back with the transmission still in the car.

A7017B-9357.jpg


A7045B-9358.jpg

Good luck with the search.
Let us know what you find.
Dave in MN
www.durableperformance.net
 
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Another slim chance , but did you instal the cup in the rear torque tube clamp, Had a V8 once where it was left out & d/shaft was hitting the bolt that holds the universal on , made a noise , but more of a tingkle noise, like someone with a 50 c piece in a can under the vehicle, Yours does sound like in the transmission gears,
 
Hi Kevin,

1. Think Dave has a point worthy of consideration in message #47 with main drive gear forward/backward movement.

2. In paragraph E., message #46 above, moving throw out bearing back & forth appears to cause "noise" & stops "noise" which could possibly cause pressure on opposite sides of internal gears to move same slightly fore & aft, & may even cause different rotating axle vibration(s) with a different pressure from one side or the other.

3. To avoid later time consuming disassembly of the drive train, seems like an article was previously written before to try to test an assembled, reconditioned Model A transmission by filling it with oil & rotating it in 1st, 2nd, & 3rd & reverse, with a half inch electirc drill, & listening for "noises" prior to installing same.
 
When I pulled the transmission last week and took it to the Rebuilder he found both the main drive gear and main shaft had over .050 end play. He tightened them up and I re-installed it, the knock was still there.

He is in the process of building a new transmission and shipping it to me. Looks like I'm going to miss Sharon :( but I will say he is trying hard to resolve the problem. I'm going to pull the rear end again tonight.
 
I wonder if the main shaft pilot spacer ring could have a flat worn on it, like many do or is missing?

http://parts.modelastore.com/show_Product.asp?ID=3667


I.E. the ring that goes on the main shaft along with the needle bearing where MDG mates to.

Another thought: what if both the bearings inside the cluster gear are the short ones? (As I remember one is short and one is long)

Wouldn't the bearings "bang around" as they moved front to rear, under different side loads on the cluster?

Or if the spacer inside the Cluster gear was too short for some reason.
 
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very interesting.. My noise was similar and the noise was caused by the main shaft bearing being bad and worn main shaft. The noise only happened in 3rd. Got it rebuilt and now 3rd gear is quite.

Glad to see the rebuilder helping you out and is putting together another one for you! Please keep us updated on what you find!
 
I pulled the rear end tonight and plan to pull the transmission tomorrow night. I may just pull the pressure plate and clutch as well just to look around.
 
Kevin,

No doubt, very many appreciate your videos & your taking your most valuable time to continue to communcate & educate "all" of us with your findings as you disassemble & assemble the drive train while trying to get your problem resolved.

So often in the past, Model A problems were posted with questions, maybe 8 or so possible solutions from experienced individuals were written, & the person posting the question(s) just rides off & disappears into the sunset, while never taking time to divulge & educate others which remedy actually worked.

Like many others who do report & communicate Model A problem findings, you are definitely an outstanding gentleman for educationally contributing to this Model A hobby.

Every now & then, some things just need to be said out loud!
 
H. L. Chauvin said:
Kevin,

No doubt, very many appreciate your videos & your taking your most valuable time to continue to communcate & educate "all" of us with your findings as you disassemble & assemble the drive train while trying to get your problem resolved.

So often in the past, Model A problems were posted with questions, maybe 8 or so possible solutions from experienced individuals were written, & the person posting the question(s) just rides off & disappears into the sunset, while never taking time to divulge & educate others which remedy actually worked.

Like many others who do report & communicate Model A problem findings, you are definitely an outstanding gentleman for educationally contributing to this Model A hobby.

Every now & then, some things just need to be said out loud!
Click to expand...


Ditto times ten ... here Kevin!!

Kudos to the rebuilder too for hanging in there!!

Thanks for all your updates
 
Afew years ago, a friend brought his roadster to me to install 3.54 gears.When I pulled the rear end,I found that the ball cup for the U-joint was missing He had been driving it that way for over 20 years,but never used it much since it would vibrate a lot over 30 mph.When I checked the trans,the D-S had pushed the main shaft forward & broke off the cast-in rear brg retainer,so I had to replace the case as well.
 
Your clutch pedal doesn't return to the top like it should. This means the throwout bearing collar return spring is weak or stretched out.

Could the noise be something as simple as the T/O bearing bouncing against the pressure plate fingers, especailly if the fingers aren't all level to each other?

Fix this first before pulling the ******.

Earlier I saw this, and that's why I asked if you were riding the clutch.
 
You should be able to spin the throw out bearing using your finger with the car in 3rd gear and the clutch pedal even with the brake or all the way up. Engine off of course.
 
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