4 Speed Noise????

[Andrew P.]

1971 350/4speed

I have what I believe to be an intermittent transmission noise.

I have only heard the noise 5 times in 3000 miles.

The best way I can describe it or the conditions in which it has revealed itself are as follows.

Noise at first sounded like engine knock but coming from transmission at idle, and increased in frequency as vehicle starts to move.

Almost sounds if two gears are hitting each other that are not fully meshed????

I parked the car and made some checks then restarted engine and noise was gone. In one instance I put the trans in reverse than back to 1st and noise was gone.

Has anyone experienced this before? I was thinking linkage/reverse adjustment but can't seem to think that it is related.

Trans/clutch are all original the only thing that was changed was throw-out bearing and noise was present before bearing was changed.

Any help would be greatly appreciated

Andrew P (48361)

[Bill I.]

Re: 4 Speed Noise????

Andy, 5 times in 3000 miles? FORGET ABOUT IT. Bill.

[Joel A.]

Re: 4 Speed Noise????

The description "sounded like engine knock" makes me think it has a broken tooth(or more) on the input or cluster shaft, but that would be constant...it wouldn't go away just from stopping and re-starting the engine. The other possibility would be if there was something floating around in there that is sometimes getting caught between two gears as they rotate...which will eventually break a tooth(or more), and then the noise would be constant. The reverse gear could be shifting out of place for a couple of reasons, but that would sound just like trying to put it in reverse without the clutch all the way in....more of a grinding noise.... Wouldn't hurt to drain it (if it has a drain plug), and see if any parts fall out...

[Wayne W.]

Re: 4 Speed Noise????

Miss-adjusted reverse lever will allow the reverse gear to hit the reverse idler and cause the exact noise you hear.

[Andrew P.]

Re: 4 Speed Noise????

Bill, Joel, Wayne,

Thanks for the replies and the info!!!

Wayne,

Which adjustment would correct this problem?
"Back Drive Control Linkage"? CSM 7-16 or
"Shift Linkage Adjustment"? CSM 7-15

[Joe T.]

Re: 4 Speed Noise????

Bill, Joel, Wayne,

Thanks for the replies and the info!!!

Wayne,

Which adjustment would correct this problem?
"Back Drive Control Linkage"? CSM 7-16 or
"Shift Linkage Adjustment"? CSM 7-15

My humble opnion: You would best serve yourself by doing all the adjustments. My recollection is that there is a sequence to the adjustment process to ensure all the adjustments are correct. If my memory serves me...OBTW: The process is in the service manual and you need to make a small "tool" out of sheet or bar stock. Good luck. I hope this corrects the issue