rearend shaking

You should post a vid of a black womans big azz shaking for those that opened this thread thinking(Hoping) it was something else. *Sigh*

Duplicate post

badmustang said:

okee thanks will look also for that.. added traction bars but before that the car shudder. mabye the u bolts are not tight enough

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While there, check for cracked or broken spring perch (on the rear end.)

Yes, it only takes an input shaft swap to create a SBF tranny, (disregarding the output shaft) but the input shaft must match the ratio of the tranny. There were only 2 ratios, a 2.32 close ratio and the 2.78 wide ratio. Easy to determine which ratio you have by counting the # of teeth on 2nd gear. You would have to do a visual to verify the BBF shaft. Don't ever rely on the production #'s found on the side of the case as all early toploader cases are identical short of that little metal ID tag.

Lots of 390's came with 4 speeds and they have the short input shaft, and yet the remainder of the tranny is the same as the SBF--28 spline output shaft. The clutch disc would be the same. The larger cube BBF would/should have the larger 31 spline output. You do not have to worry about that end since you already have a driveshaft hooked up.

As I said, it is a shot in the dark that this is your problem, but it seems like you have covered the normal items.

Another thought, you might want to take a dial indicator and check the run-out of the new flywheel as it is installed on the back of the crank. Not sure of the exact spec, but I would expect it to be something less than .010".

badmustang said:

how much play does the drive shaft have in the tailhousing...

i was unther the car and wiggel the drive shaft up and down (near the tailshaft) i could wiggel it a littel bit up and down but not side ways..

is that a problem or does the drive shaft not must have a wiggle..

sorry for my englisch (may be yo know what i mean)

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There will be a slight amount of wiggle as there needs to be a little play between the tailhousing bushing and the driveshaft yoke. It shouldn't be much though--ever so little. Another "possible" sign of a bad tail housing bushing is a transmission fluid leak at the rear seal.

If you think there is excess play, the bushing can be replaced. You would need to unbolt the tail housing in order to do it--not a major job except for the fluid mess and needing to remove the shifter. You should also check the condition of your yoke where it rides in the bushing. They are available too.

Shudder

Clutch Disc.