4 speed problem

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Bob B

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I have a 1969 GTS 383 4 spd with a problem. Shifting from neutral into 1st I have a severe shimmy/vibration. Once I am rolling it goes away. No problem from 2nd to 3rd to 4th. Any clues what could be going on. I have had the tranny rebuilt, new clutch, pressure plate, the bushing and bearing at the front as well as the rear tranny mount, thanks for any help or suggestions.
 
"shimmy/vibration" when your sitting still?
No Dave, it is when I am just starting out in 1st, I sort of have to eeze out slowly on the clutch pedal until it slowly grabbs other wise it will like I mentioned shimmy/shake.
 
Sounds like clutch chatter. Could be any number of things, but is usually contamination/oil on the clutch disk.
 
Sounds like clutch chatter. Could be any number of things, but is usually contamination/oil on the clutch disk.
With everything new at assembly and clean not likely an oil issue so what other things should I be looking for?
 
Inertia , I did have the fly wheel checked and machined and reinstalled and no real change
 
"New" doesn't necessarily mean "good". Several folks here found that out recently. Old clutch did not have the "shimmy/vibration"?
What condition is the pilot bushing in?
Some things you might check...…….
Loose bell/trans mounting bolts.
Fat spot on the disc.
Fingers not adjusted to same height. Bearing not contacting/releasing fingers evenly, or not attached to the fork properly.
Fork pivot bent/worn, or fork not completely on pivot.
Off center/twisted clutch plate in the cover.
 
Scrutinize and dress the crankshaft flange with a flat file, for any abnormality,
Pilot bushing.
If you still have old clutch, put it in for test.
What Dave said.
Good luck.
 
Sorry with the delay on a response, Dave I will address your suggestions and thanks for all the advice you fellas have given me , take care , Bob
 
Mine will do the same thing if I release the clutch slowly and with minimal engine rpm. If I just release the clutch a little quicker and just a little more rpm than everything is fine.
In my case my problem might just be getting the hang of driving the 4 speed again. Its been a long time since I had one and they were all 4 bangers
 
Motor mounts in good shape?
Transmission mount in good shape?
How about the "Z" bar (torque shaft) bushings and linkage pivot points?
Everything lubricated and moving smoothly from the pedal to the clutch fork?
If all the above checks out ok, the big block torque shaft is known to flex at the arms causing excessive chatter especially with a heavy duty clutch, the fix is to weld braces on to the arms to keep them from flexing.
 
I have a 1969 GTS 383 4 spd with a problem. Shifting from neutral into 1st I have a severe shimmy/vibration. Once I am rolling it goes away. No problem from 2nd to 3rd to 4th. Any clues what could be going on. I have had the tranny rebuilt, new clutch, pressure plate, the bushing and bearing at the front as well as the rear tranny mount, thanks for any help or suggestions.
I recently went thru same thing on 69 GTS, I installed new z bar bushings and ball mounts,checked pedal bushings,pedal did not feel right,was a little hard to push and chattered and vibrated in first gear.the problem was clutch fork pivot mount in the bell housing,not sure what this piece is called,anyway it was cracked and flexing when I depressed clutch pedal. I was able to remove inspection cover and removed clutch fork out of bell housing,removed the two bolts that held the bracket on,inspected it and was cracked allowing clutch fork to move when pedal was depressed. I happened to have another bell housing I acquired and removed the pivot mount and reinstall in car. Works perfect now,I have not been able to find this piece anywhere. I could not see cracked in piece until I got it out of bellhousing
 
I recently went thru same thing on 69 GTS, I installed new z bar bushings and ball mounts,checked pedal bushings,pedal did not feel right,was a little hard to push and chattered and vibrated in first gear.the problem was clutch fork pivot mount in the bell housing,not sure what this piece is called,anyway it was cracked and flexing when I depressed clutch pedal. I was able to remove inspection cover and removed clutch fork out of bell housing,removed the two bolts that held the bracket on,inspected it and was cracked allowing clutch fork to move when pedal was depressed. I happened to have another bell housing I acquired and removed the pivot mount and reinstall in car. Works perfect now,I have not been able to find this piece anywhere. I could not see cracked in piece until I got it out of bellhousing

Brewers transmission sells the pivot point.
Also caution B & E body's use a different pivot point than A bodies.
 
Sounds like you are talking about clutch chatter when starting from a stop. As mentioned above.............engine mounts.......weak/ flexing clutch linkage or fork..........or even the type or condtion of the disc. Are you using a spring center disk? A solid hub disk can be a big problem on the street. "Is it possible" the spring center assy has been damaged? And be CERTAIN that the disk is not getting oiled on
 
Bob, had this exact issue. I changed the pinion angle using 4 degree shims and changed the springs. Talking to guys who have raced 4 speeds for years, they all say that what you are describing is rear suspension related. To see if this is the case, you could put 3 to 4 clamps on the front section of your springs. If it helps, you know the rear end was rotating up to fast causing the extreme vibration. I made my clamps from steel purchased at home depot.
 
I caught the pivot point when I changed my duster over to 4-speed.
Its pretty obvious between the A and B&E pivot.
They are visually different, compare what you have to their website.
 
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