Thomas Davey
Member
Does anyone know what the minimum spline engagement is in inches for a 727 transmission yolk? I moved the rear back an inch and am wondering what this does to the length inside the trans. Will an inch shorter hurt? Thanks!!
727 yoke engagement
- Thread starter Thomas Davey
- Start date
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TrailBeast
AKA Mopars4us on Youtube
you shouldn't have more than about 1-1.5 inches visible.
This assumes you have the non booted rear seal.
This assumes you have the non booted rear seal.
Thomas Davey
Member
I know what the protrusion should be. I need to know in inches what the minimum engagement internally should be.
Who is to say what minimum is. I guess if you have 3 inch play on a 6-8 in yoke, you might have issues during a hard launch. Tell us what your measurements are. Driveshaft can move 1 inch either way. Standby the smart folks will chime in. That’s why most recommend 1 inch play +- 1/4.
There are different legnth yokes with different legnth splines in them so it’s hard to say. Kim
Daves69
Well-Known Member
I'd think an inch less spline engagement from stock might translate to vibration (one of those ya' can't seem to find) and eventually fail on you.
Maybe measuring using this order form can help you decide...……….
http://www.dynotechengineering.com/...m/adobe/1 pc driveshaft trans to cl.pdf?la=en
I agree. U still need to be well past the bushing in the tailshaft. Kim
Thomas Davey
Member
Thanks Kim!! I have some numbers: Yoke cylinder is 5.5 in. long, with 3.0 inches into the trans, 2.5 in. gap left between the rear end of the yoke cylinder and the trans seal. Is 3 inches into the transmission enough engagement into the bushing? Thanks all!!!
I would say not. I like 1 in from the yoke bottoming into the tailshaft. How far into the yoke do the splines start? Kim
CudaFactHackJob
Well-Known Member
The problem is that the further back the u-joint is then the more prone to vibration that front yoke is. Plus even a small amount of vibration will wear out the bushing and yoke. So: it depends on how well balanced the driveshaft is. I say drive it and see if it vibrates.
Thomas Davey
Member
The splines start right at the front end of the yolk. So there is 3 inches of engagement into the tail shaft. Is that 3 inches far enough into the tail shaft to fully engage the bushing? How far in from the end of the transmission does the bushing start? Thanks everyone!!!
I would think u are too short. U will likely only be as far as the bushing is long. Kim
famous bob
mopar misfit
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This is the way every driveshaft builder I have used (4) said to measure it when having one built. Both Mopars and chevys .
Doesn't make any diff on spline length------
Thomas Davey
Member
Yep, Kim, you are right. An old 727 guy said the same. I need a longer shaft by 1-1/2 inches. And a new bushing and seal.
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