How much "freeplay" should there be back & forth in an installed driveshaft to allow for suspension movement? I Switched from 4 speed muncie to a 200-4R and from a 10 bolt to a Ford 9". I know there is no difference in length between the muncie and the 200-4R, but the 9" changed things. The stock shaft was too short. Tranny output shaft was only 1.5inches into the slip yoke. I took it to a driveshaft shop and they lengthened it. Now it's a tight fit to get it in place and It has 5/16" freeplay back & forth before bolting the ujoint to the rear yoke. 5/16" doesn't seem like much. Is that enough?

With the car sitting at ride height, the yoke should be approx. 3/4" out from being bottomed in the trans.
5/16th is probably too tight, i would take it back and shorten it slightly.

So it should be shortened about 7/16 or 1/2" so I would have a total of about 3/4" from being bottomed out.

I'd be concerned that suspension travel would pound the yoke into the transmission output shaft running at 5/16". I've always ran 3/4" to 1".

With only 5/16", I bet it was tough getting the driveshaft bolted up to the rear yoke?

Yeah, almost impossible to get it into place. Just seems like way too little tolerance.

As a thumb rule, I always went by there being enough room to get the U-joint over the yoke.

If you had to force it or remove the bearing caps from the U-joint it is definately on the tight side.

Better safe than sorry -- a busted 200-4R tranny is an expensive fix.

Had it shortened today. I'll try it in tonight and see how it fits. If it fits what is the torque spec for the U-bolts at the rear yoke? Can't find it listed anywhere?

I believe torque is like 15ftlbs, Dont overtighten them because you can crush your caps/needle bearings. They have lock washers so 15 should be plenty.

"spark plug tight" ;)

Like Ryan said, you can damage the bearings if you tighten them too much.

I have a similar problem. mine is 1 5/8th out, so I guess I should have retubed? Would this cause a vibration in a vehicle?