Driveshaft question

[flatgreyG]

I am trying to find out if there is a vehicle out there I can use the drive shaft from without spending hundreds on new or a cut and balance. The problem I have is I can not find a simple method of telling what size I need. I have a
th350 and Ford 9". It measures 44" from trans seal to center of rear yolk. I have about 1/2" of spline sticking out of tranny and I do not have tranny yolk yet. Is there a way to get a measurement from this info?

Thanks in advacne!!![S

 

[Bamamav]

You really need a tranny yoke first, then you can measure from the center of the u joint to the center of the rear u joint. You want the yoke centered in the tranny and the rear at ride height.

Once you get your measurements, head out to the bone yard and hunt until you find what you want.
There are many u joints made, so you shouldn't have any trouble finding one to fit the yoke and the driveshaft even if they are a different make.

 

[zzrodder]

Measure the yoke on the 9" first for the width of the U-joint and size of the cups. As Bamamav said, you need the tranny yoke installed in the trans. I usually bottom it out and then pull it back 3/4" to allow movement during suspension travel, though it may vary by vehicle depending on the suspension type and travel. Quite often you can see on the yoke where it originally sat by the wear from where the seal touches it. A lot of older Chevys and 9" Fords used the same size U-joint (50's I think) so you may find a ready to go shaft, but unlikely... There are also some interchange U-joints that have two different size ends that can help with swaps like this.
Most often what I look for is a driveshaft to fit the trans and one to fit the rearend that have the same diameter pipe, then it's a simple matter of chopping one yoke off and welding the yoke from the other to it, done it myself a couple dozen times, but most machine shops should be able to do it for you fairly cheaply.

 

[Dr Crankenstein]

Hey, ZZ? Didn't you post something before... about joint phasing and a homebrew balancing trick?

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[flatgreyG]

Appreciate it fellas. I was trying to save a trip and pick up a driveshaft and yoke at the same visit to the yard. I have a couple calls in to some friends with parts piles in their garages, hopefully one of them has a yoke.

 

[chuckp]

1/2 way down he tell more on to determine driveshaft length


http://www.hotrodhotline.com/md/html/drive_shaft_basics.php
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[zzrodder]

Hey, ZZ? Didn't you post something before... about joint phasing and a homebrew balancing trick?

.

Could be....[S For better or worse perhaps, I've never worried about phasing the joints (5 degrees ?), though I've used the farm tech balancing method of putting hose clamps on the driveshaft for balancing. Used on an obviously wobbly shaft - vehicle running in gear on jackstands , touch the spinning shaft with chaulk to find the high spot(s) and add clamps with the screw piece on the opposite side of the high spot to balance it. Sketchy and somewhat haywire, this actually worked for me on a shaft that a buddy welded together crooked.

 

[Dr Crankenstein]

Yeah, that's the one. Thanks zz.

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