1951 Ford driveshaft - which end is which?

[Ken Henry]

I was a little overzealous and removed both U-joints from my driveshaft without marking which is the slip joint end. Now I'm not sure which end to attach to the transmission yoke!

The main difference I see is that one end has the balance weights 8 inches from the joint while the other is more like 4 inches. The 8 inch end is a little oilier...

Thanks for any help!

[RalphM]

Assemble it and have it rebalanced, then it won't matter.

[rotorwrench]

If the shaft was dynamically balanced, then it should be able to go either way. As far as an oily end is concerned, you have to imagine which way oil will go when the shaft is in normal service. I'd say it goes to the rear since the relative wind under the car will blow it that way and momentum will also make it gravitate that way. That would make the oily side the front of the shaft.

[Kube]

Originally Posted by rotorwrench

If the shaft was dynamically balanced, then it should be able to go either way. As far as an oily end is concerned, you have to imagine which way oil will go when the shaft is in normal service. I'd say it goes to the rear since the relative wind under the car will blow it that way and momentum will also make it gravitate that way. That would make the oily side the front of the shaft.

I agree 100%.

[flatford8]

Is there oil on the bottom of the floor, near the end of the transmission? If the driveshaft has oil on it I would think it would get sprayed up there from the shaft turning. Of course, if there's oil over the rearend, then I'm only adding to the confusion.... Sorry.... Mark

[Ken Henry]

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Originally Posted by rotorwrench

If the shaft was dynamically balanced, then it should be able to go either way. As far as an oily end is concerned, you have to imagine which way oil will go when the shaft is in normal service. I'd say it goes to the rear since the relative wind under the car will blow it that way and momentum will also make it gravitate that way. That would make the oily side the front of the shaft.

So you think the oily end goes to the rear? Later in the post it sounds like you are suggesting the front. Seals at both ends were leaking. Looking at the underside of my floor, there is more oil spray at the differential end, so I think I'll put the oily end toward the rear. Hopefully won't matter.

It will be a little while before I can reassemble because the hole for the U-joint race is enlarged, the race just spins around in there. Need to wait for a replacement...