New shudder....

6

61ragtop

Member
I have a shudder that seems to be rpm based. At about 1500-2000 rpm It starts to shudder in all gears when there is load on the drive train. When I back out of it, it seems to go away. I have changed a few things over the winter too so here they are.....


-I went from a stockish converter to a 9.5 inch 3200 stall.

-I hooked up the lock up with a TCI kit (never had it working before)

-Switched to full manifold vacuum for vac advance.

-Had 2 piece drive shaft rebuilt with a slip yolk in the rear half

No changes were made to the drive train so I do not think it is the drive shaft? It is also rpm not speed related so that alo makes me think it is not the shaft.



Here is a link to my motor tranny specs minus the new changes....

http://www.chevytalk.org/fusionbb/showtopic.php?ti...
 
61ragtop said:
I have a shudder that seems to be rpm based. At about 1500-2000 rpm It starts to shudder in all gears when there is load on the drive train. When I back out of it, it seems to go away. I have changed a few things over the winter too so here they are.....


-I went from a stockish converter to a 9.5 inch 3200 stall.

-I hooked up the lock up with a TCI kit (never had it working before)

-Switched to full manifold vacuum for vac advance.

-Had 2 piece drive shaft rebuilt with a slip yolk in the rear half

No changes were made to the drive train so I do not think it is the drive shaft? It is also rpm not speed related so that alo makes me think it is not the shaft.


Here is a link to my motor tranny specs minus the new changes....

http://www.chevytalk.org/fusionbb/showtopic.php?ti...
Click to expand...

the highlighted parts have me rather confused here?
when testing you always try to isolate each component, to find the source of the problem, since it was running fine before the mods...first verify theres enought transmission fluid,and your ignition timing and carb is set up correctly, HAVE you changed the driveshaft length or angles?
a minor change in the drivetrain can occasionally cause problems, as can swapping yokes, or installing a differant transmission mount, etc.
if the engines not getting the correct ignition advance and consistant fuel/airratio, that can cause problems, accellerator pumps can get out of adjustment, floats, power valves, fuel pressure, etc. verify the TV cable is correctly adjusted, and theres no vacume leaks
first test... get up to speed (60mph-70mph) and put the engine in neutral and see if the vibration instantly goes away, if it does its not likely to be the tires wheels or drive shaft, next test, swap back to the original vacuum sourse asa quick test, to see if that changes anything,and disconnect the lock-up connections on the tq converter temporarily as a test,
hold the engine rpms with the throttle at the rpm range where the vibration is worse in neutral as you coast to a stop, this will tell you some info on if its transmission or engine related if it drops with speed or stays constant.
let us know the results. now Im assuming youll find that the vibration is as youve indicated only under accelleration in gear, if so Id suggest calling the converter manufacturer for thier input, because it seems to be converter related

this might help
viewtopic.php?f=64&t=1216&p=2620&hilit=700r4#p2620
 
Well Grumpy I have checked things out and here is what I found, or didn't find.

I unhooked the conv and ran the engine with out it hooked up to eliminate the motor and all was good.

Then when I hooked it back up and clocked it at a different position to the flex plate to take it for a drive to test it as you said to........NO MORE SHUDDER/VIBRATION!!!!!!!

Just thought I would let you all know the final verdict.

Thanks again Grumpy
 
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