Driveshaft slip yoke tech

[cadillac_al]

Well the slip yoke on my K20 is finally worn out (again?). I think I had it rebuilt about 25 years ago but I'm not positive. Anyway I have a few things puzzling me. This slip yoke has remnants of the blue nylon/teflon glidecoat or whatever they call it. Did the original slip yoke have that stuff in there? If not then I guess I did have this shaft rebuilt some years ago.

When looking at new Spicer slip yokes I see a lot of them with the blue plastic stuff. I guess they say it makes for a tighter joint and is easier to balance. In that case, it looks like grease will not go in there. It seems like it is almost a waste of time to grease a slip yoke if the grease won't go past the blue plastic. All the grease seems to do it keep the water out of the end hole. Is that the way these work?

I am hoping to have a driveshaft shop put a new slip yoke on for me and go another 25 years. It looks like all I need to do is give it one squirt of grease every year to keep that vent hole plugged to keep water out.

[mongocanfly]

its blue nylon...get it replaced if its worn..youll be good to go
supposed to help with vibration and cushions the splines

copied this
That “blue stuff” on the splines of the slip yoke is called Glidecote. The blue, nylon, wear-resistant coating on Spicer yoke shafts helps reduce vibration. The coating is machined on the splines for a tight fit. Slip yokes without Glidecote can be purchased, but they are considered an agricultural shaft and may not balance as nicely but they do offer superior strength. For most, Glidecote is a great way to go and will be found on almost every factory drive shaft with a slip yoke in the shaft. If you have an older driveshaft with pealing Glidecote, the only way to repair it is with a new slip yoke.

[cadillac_al]

More tech: Does anybody know why the K10's have the slip yoke at the transfer case and the K20's have the slip yoke at the rear axle? That slip yoke takes quite a beating down at the axle end and gets whipped by lots of side loading as the rear axle bounces and twists down rough country roads. If the slip yoke was up near the transfer case it could live a nice calm life of moving in and out a little with the suspension movement and would be up higher away from water ingestion.

I think this was a penny saving decision so the K10's and K20's could use the same driveshaft. They just used a different yoke to attach the driveshaft to the 14 bolt rear axle. I think this is one instance where I am smarter than those engineers. If the cost of replacing my slip yoke seems too expensive and I have to spend $600 for a completely new driveshaft then I will but a 1310 slip yoke at the transfer case and a 1350 U-joint at the rear axle and let the slip yoke live a calm life and replace a 1350 U-joint every once in a while.

[jeffahart]

Al, not sure what's up with that. My slip is at the transfer. K20 been like that forever.

j

[mongocanfly]

might be a good question for Keith...
ive seen them run both ways..
i prefer the slip at the driven end though

[pjmoreland]

With the slip yoke at the transmission, the center support bearing has to flex as the suspension travels up and down. Maybe the bigger center support bearings aren't designed to flex.

[cadillac_al]

The old K10's and K20's don't have a center bearing, just a one piece driveshaft. The 80's trucks probably had the slip at the transfer case.

I managed to find a nice driveshaft on one of my spare K10's. I will put the slip yoke at the transfer and use a conversion u-joint at the rear axle and keep a spare conversion joint under the seat.

[pjmoreland]

Interesting. I did not know that.

My '89 K1500 SWB has a single piece driveshaft with a slip yoke at the transfer case.