Slip yoke allowable length

[goochieman83]

So I just got a cv shaft built for the k5, but when I went to pick it up I noticed the rear slip yoke wasn't splined all the way to the end. My stock slip yoke has 6" of travel where this one has 3 1/2". Is this allowable or could it cause problems. I am getting the shaft lengthened slightly, as I installed it today and it only mated to the output shaft by roughly 1/2". What are your thoughts?

 

[truck-oholic]

So I just got a cv shaft built for the k5, but when I went to pick it up I noticed the rear slip yoke wasn't splined all the way to the end. My stock slip yoke has 6" of travel where this one has 3 1/2". Is this allowable or could it cause problems. I am getting the shaft lengthened slightly, as I installed it today and it only mated to the output shaft by roughly 1/2". What are your thoughts?

I am having a bit of trouble understanding your problem. Do you have a slip yoke transfer case or a fixed yoke transfer case with a splined stub and slip yoke in the driveshaft? If it's a slip yoke transfer case and you now have less than the stock amount of slip in the yoke then I would say yes, you are probably going to have problems, especially if you are lifted with a flexy suspension.

 

[goochieman83]

I am having a bit of trouble understanding your problem. Do you have a slip yoke transfer case or a fixed yoke transfer case with a splined stub and slip yoke in the driveshaft? If it's a slip yoke transfer case and you now have less than the stock amount of slip in the yoke then I would say yes, you are probably going to have problems, especially if you are lifted with a flexy suspension.

Yes it is a slip yoke rear and yes the cv shaft that I had built has a different slip yoke than stock. The length of the rear slip yoke spline is actually 2 1/2" shorter than stock. I told the guy that the slip yoke was splined different than stock and he said he would lengthen the driveshaft to accommodate for the difference. I didn't think that would work and wanted to get some input.

 

[blazinzuk]

The rear slip barely moves. Unless you jump but even then your axle moves forward as the axle droops. I measured it once on Horton ( flexes pretty good) and I used barely an inch

 

[goochieman83]

Ok, that was what I was curious about. I just don't want to install the cv shaft and a little flex cause the slip yoke to come out.

 

[truck-oholic]

So, I am going to ask this question just in case. Is your rear axle pinion currently pointed at your t-case output as it should be for a CV shaft? If not, you are going to have to do that and you will want to do it before you get your shaft lengthened. Would really suck if you got it lengthened and then you rotated it up afterwards and had to have the shaft shortened some to compensate.

 

[Phil513]

So, I am going to ask this question just in case. Is your rear axle pinion currently pointed at your t-case output as it should be for a CV shaft? If not, you are going to have to do that and you will want to do it before you get your shaft lengthened. Would really suck if you got it lengthened and then you rotated it up afterwards and had to have the shaft shortened some to compensate.

If I can step in, if so, where does one purchase the shims to accomplish this? Or do you have to cut and reweld the spring perch?

 

[wetoolowdingbangow]

If I can step in, if so, where does one purchase the shims to accomplish this? Or do you have to cut and reweld the spring perch?

Ive seen really old shims accomplish such steep angles but I highly recommend avoiding that if you can. that big shim means your center pin has to be pretty long making it weaker. If it came out you would be in a ditch in a split second lol

I started with fresh perches. Any rear end shop could do it for $100 I think.

 

[goochieman83]

So, I am going to ask this question just in case. Is your rear axle pinion currently pointed at your t-case output as it should be for a CV shaft? If not, you are going to have to do that and you will want to do it before you get your shaft lengthened. Would really suck if you got it lengthened and then you rotated it up afterwards and had to have the shaft shortened some to compensate.

You are correct, the pinion is close to 0 right now and will need to be rotated upward. Even so, the driveshaft is too short. I assume the rotation of the pinion might cause an inch (possibly) of change which would still leave me with around 2" of spline contacting the output shaft. That would give me an 1 1/2" of travel.

 

[truck-oholic]

If I can step in, if so, where does one purchase the shims to accomplish this? Or do you have to cut and reweld the spring perch?

Cut and reweld new perches in is the best solution. Lots of companies sell new perches. Ruff Stuff Specialties, DIY4X, and WFO Concepts are good places I use. Degree shims can also be purchased a number of places. DIY4X and WFO Concepts both carry those also.

On my build I cut and turned the rear end but on the front I used degree shims for two reasons. (1) Proper caster is more important than driveshaft angle on a steering axle (2) My front axle is a dana 60 so it has a cast perch as part of the differential so you have to cut and turn the axle tubes if you don't want to run degree shims. I wasn't looking to do that much work and degree shims can be easily swapped out if you need to make future adjustments.