syncro/stop ring noise troubleshooting

[lancer402]

I have had noise in my 568 since rebiulding it a year ago. I havent driven it much due to this. The noise in in neutral with the clutch ingaged , sounding like a bad bearing on the input shaft. There is more brass particles in the oil than normal.

So I decided to go back in a figure it out. The brass makes you think syncro.
But first, after removing the input and interm. shaft. I put the input shaft back in and started the engine. This is with the bearing support plate on but not the gear selactor cover or end cover. It purred, with no noise at all. Some might think this will hurt the bearings since there was no oil in the trans. But a taperred roller bearing can be lubricated with the oil you could place on the head of a needle. Anyway, then I placed the intermediate shaft in the trans with out 1-4th gears on it, but put 5th gear on the outside of the bearing support plate. Started the engine and again NO noise. SO then I placed 1-4 th grears on the interm shaft and left 5th gear off. Started the engine for about 20 seconds and sure enought the noise is there. So then I reached in the top cover and moved the 1-2 syncro a little. No change in the noise at all. But when I moved the 3-4 syncro the noise changed a lot.

So the problem is in the 3-4 syncronizer. I carefully disassembled the syncro and could see a lot of brass particles on the tappered cone of the 4th speed gear. I have never had a stop ring go bad like this.

Can anyone assure me that this stop ring is going bad and just needs to be replaced. I cannot see anything else damaged in the 3-4 syncro.
Have two stop rings on order and should have the car ready for SDAC.

Could the cable be out of adjustment?

Thanks
Andy
Cincinnati

[lancer402]

Clif, you out there??

[minimopar]

When you say "moved the syncro a little" are you talking about the slider? The outer sprags on the stop rings should always be held by the slider. So with the trans in neutral and the car not moving, the main shaft, the sliders and the stop rings should all be stationary while the gears all spin on the shaft. Is one of the stop rings spinning? Maybe the 4th gear stop ring is being pushed into the cone for some reason? Does the slider center itself properly when in neutral? There are 3 little tabs pushed by springs that are supposed to make the slider snap firmly into all 3 positions. Maybe it is somehow dragging the stong ring or maybe there is something wrong with the stop ring. Is 4th gear out of position on the mainshaft at all? I can't remember exactly, but there are several clips and spacers that position the gears along the shaft.

[lancer402]

Thanks for the help Yes, the slider. The ring that the shift fork goes into. Sorry I should have been a little more detailed.
I moved the slider like the shift fork would and the noise varied a lot. It has to be in the 3-4 mechanism. The stop ring(s) are not moving, to answer your second question.
Yes the slider centers itself when in nuetral. 4th gear doesnt look out of position at all. I have all the right snap rings as well. Tonight I measured the i.d. of the 4th gear and o.d. of the shaft and compared them to another 568 gear and shaft I have. They are the same.
tomorrow I pick up 2 new stop rings and Ill see if this remedys the noise. If not I was thinking about installing the other 4th speed gear on the shaft.
I believe a 4th gear from a 555 would be the same as well, although I have a 4 th gear from a 568 that is already apart.

Quote:

Originally Posted by minimopar When you say "moved the syncro a little" are you talking about the slider? The outer sprags on the stop rings should always be held by the slider. So with the trans in neutral and the car not moving, the main shaft, the sliders and the stop rings should all be stationary while the gears all spin on the shaft. Is one of the stop rings spinning? Maybe the 4th gear stop ring is being pushed into the cone for some reason? Does the slider center itself properly when in neutral? There are 3 little tabs pushed by springs that are supposed to make the slider snap firmly into all 3 positions. Maybe it is somehow dragging the stong ring or maybe there is something wrong with the stop ring. Is 4th gear out of position on the mainshaft at all? I can't remember exactly, but there are several clips and spacers that position the gears along the shaft.

[lancer402]

Thanks for the help Russ. After trying new stop rings with no sound reduction
I switched the 4th speed gear with one I had and the noise disappeared. I looked at the gear making the noise with an eye piece maginifier and I could see some wear on the driven side of each tooth. So I learned a little bit here anyway.

Andy