DriveShaft installation. URGENT!!!

[prozachappy]

Took my driveshaft and yoke down to have it balanced today. Been having vibration, and keep blowing the rear seal on my tranny. When I picked it up this evening they had balanced it..but also painted it with flat black! Now there's no factory paint mark to realign to the flange!!! Also the u-joints were bad/old but that is something I can do myself no problem. Except one thing...when I got my driveshaft back it was in 3 pieces. The shaft, the yoke, and the piece that attaches to the rear companion flange. Problem is..which end of the shaft does the yoke go on...and which the flange piece! Does it even matter, since the shaft is now balanced? Is there a front and back to the shaft? Is it gonna matter if I can't realign with the factory paint marks? PLEASE HELP...gotta get to work in the morning!

 

[james t]

If its in pieces, than its no longer balanced (unless they made some alignment marks on it). Basically, it needs to be installed 2 ways-

1- The slip yoke must be inserted so that its balanced. This is something only the driveline shop can do. If they took it back apart without marking it, then it wont be balanced when you stick it back together

2- It needs to be in phase. This means, both U-joints (the one at the transfer, and the one at the rear end) need to be lined up with each other. In other words, it needs to look like this +-----+ and not[/] like this +----x

 

[prozachappy]

Thanks for the info James. My yoke has the inner spline that just slides into the rear of the transmission. I've droped my shaft before for towing, the yoke only slides in one way. I know my u-joints have to face +.....+, but I don't know which end of the driveshaft they took the yoke off of. The shaft looks the same at both ends with the yoke removed. And what about the paint mark on the end of the shaft...that lined up to the paint mark on the companion flange at the rear diff. ? Is not putting the driveshaft back on exactly (hole for hole) going to effect balance?
Thanks

 

[95expledbau]

I'm not sure if you fixed it yet but here's my suggestion. To determine which side of driveshaft is front or rear look for the little balancing weights. They're suppose to be in the REAR. As per aligning it with the flange, look at the flange closely. It should have the shape of the piece that bolts to it sort of "embedded" in rust. Poviding the yoke slides in one way and you didn't roll the truck w/o the shaft in it you should be pretty close.

Hope this helps

 

[prozachappy]

Well, problem is my shaft has factory weights at both ends of the shaft. One had the number 4.5 on the weight, the other 2.7. My thougths were that the end that the yoke went on probably had the lighter of the two weights on its end. I ended up going back to the shop today..cause the spicer u-joints they sold me were to big. As far as which end is which the owner said it really didn't matter cause the shaft is now balanced. As far as the paint marks for realignment with the rear flange...he just laught (at ford) saying it doesn't really matter just bolt it up and make sure your yoke slides into the tranny good. They run hundreds of fleet vehicles through there weekly so I trust his judgement. But I ended up sanding the paint down enough that I found the factory yellow mark anyway ( the yoke did have the lighter of the weights on its end). But like he said I just bolted it back up...and all is well.