Have much play from front to rear should a driveshaft have. I have 1968 4442 with a 4 speed tranny. My current driveshaft is 56” from center of u-joint to center of u-joint. I thought it was an original OEM driveshaft. It is not that easy to take in and out and probably has at the most 1/2” forward and back play when unbolted. How much back and forth play should I have? I thinking more like an inch would be more correct but want to check what others think.

 

I guess I am not understanding your question. With the driveshaft bolted to the differential, there should be no forward and backward movement.

 

If I am understanding you correctly if you unbolt the driveshaft at the back U-joint it will only move forward 1/2" before it bottoms out in the transmission ? That just barely sounds like enough to get it out of the yoke. I think it should be more like an inch. It also depends on if you are doing it with weight on the wheels or with the car hanging on a lift with the rear wheels hanging down.

 

Yes this is exactly what I am talking about. It barely enough to get it out of the rear yoke. And it is with the wheels on the ground and full weight of the car.

 

That is probably on the tight side but if it is with the weight on the wheels it will probably be fine. If you put the car on a lift with the wheels hanging it will be easier to get the shaft out. Unfortunately the only way to get more clearance is to cut the yoke some or have the driveshaft shortened. If you plan on aggressive driving it would probably be a good idea to do something about it. You don't want the yoke bottoming out in the trans.

 

Thanks for your thoughts! I was debating whether I should get it shortened by 1/2” or 3/4”.

 

the general consenses is 3/4 to an inch of clearance. Google how to measure a driveshaft. There are numerous DRIVE SHAFT BUILDER websights detailing how to measure properly

 

Some driveshaft mfg say 1" minimum, 1.25" is ideal.

 

Length needs to be enough to keep the slip splines engaged at full suspension travel and not bottom-out on yoke/tail shaft at full suspension compression.