Help! Transmission prob.'s !!

[hollywood]

I have an 81 Chevy 2 wd Swb Truck, been changin from an automatic transmission to a 3 sp manual. Having trouble with making the drive shaft work right. !!?? Is there a difference in the drive shaft lengths or the yoke lengths Gotta a lotta play goin on in the yoke area, and I measured both of the trans. and they are both the same length. Changed U joints, didn't help any. I'm gettin a lot of vibration, can't figure out exactly why. Already checked weights on the driveshaft, so for you proffessional Chevy Mechanics, can ya let me know if there is a difference in the drive shafts Please Tell me all ya know on this one. My Chevy is down and needs to be on the road quick. Thanks,

[83]

what year trans came out and what year going in? only thing comes to mind is number of splines

[Pontiac1976]

I believe that the two different drive shifts lengths. To be sure compare the length of the trans to see.I think the manual is a little longer.

[hollywood]

TRANS ARE THE SAME LENGTH,28 INCHES FROM NOSE TO TAIL, ALREADY CHECKED ,CHECKED SHAFT BEARING,ALSO CHANGED U-JOINTS,NO CHANGE IN MY PROBLEM

[hollywood]

DONT KNOW THE YEAR OF BOTH TRANS BUT CHECKING THE DIFFERENCE IN THE SPLINE IS THE ONLY THING I HAVENT DONE. THANX

[reiners81chevy]

Just wondering....did the truck have play in it before you changed the trans? also it could be an internal problem in the tranny too. Just a couple of points to consider. Hope everything works out alright.

[hollywood]

NEVER HAD THIS PROBLEM B-4 I CHANGED TRANNIES AND THE INTERNAL PARTS LOOK NEW BUT I COULD HAVE OVER LOOKED SOMETHING . THANKS