External slip yoke eliminators...

[wetoolowdingbangow]

Ok so I've been on the hunt for what will get my driveshaft woes under control. I've called all the big boys regarding my binding issue and it's quite obvious I need to throw a cv into the equation. I know the slip yoke isn't the best thing for flexing but I'm not convinced I'd run that travel out but the last thing I want to have is it falling out during a trail.

I did a bit of research and found that there are a few people who are using an external sye by having a flange made that is bolted to the end of the output shaft on the tcase through drilling and tapping. This would allow me to run a cv shaft, eliminating my binding issue and I can run the correct pinion angle.

Does anyone have experience or thoughts on this? I can make a jig to keep the drill straight very easily. I don't see there being any issues as long as the bolt is of a decent size. The bolt really wouldn't see much load unless you ran out of slip in the driveshaft which regardless you would be breaking things.

 

[82355]

Which transfer case do you have?

Martin

 

[wetoolowdingbangow]

I should have mentioned that...

Np208.

 

[big dan]

Ive done this on the 208 in my scout. took the t-case apart so that I had just the output shaft and tail housing to work with. Used a flange off the front output and cut the rear output shaft down to where the spline was the same length as the spline of the flange, I think I cut off 3-4 inches. Then I cut the same off of the tail housing and machined it to take the same seal as the front output. I then drilled and tapped the output shaft to take a 1-1/2" long 1/2" bolt and had to make a spacer so that the flange would bottom out on the bearing otherwise it would slide back and forth on the shaft and probably leak. I then cut down a factory front drive shaft and used it (scout with chevy drivetrain, my rear shaft is only like 21" long) with no vibrations up to 40-45mph or so.

I thrash on this thing pretty hard and haven't broke it yet but I constantly worry about it blowing the bolt out of the end of the output shaft. I don't know what the likely hood of it actually happening and like I said it hasn't happened yet but I worry about it. Im watching craigslist for something better to swap in with a bolt on style yoke but until then Im gonna keep pounding on my 208

As far as the factory slip yoke goes, I don't see you pulling it apart. Since its centered on the axle it doesn't travel much as the suspension articulates so it would really only move a lot if the suspension were to completely unload which would require leaving the ground. My truck I used to wheel had 56" rear spring and would use every bit of a 15" travel shock and I never once pulled the slip yoke apart.

 

[wetoolowdingbangow]

Ive done this on the 208 in my scout. took the t-case apart so that I had just the output shaft and tail housing to work with. Used a flange off the front output and cut the rear output shaft down to where the spline was the same length as the spline of the flange, I think I cut off 3-4 inches. Then I cut the same off of the tail housing and machined it to take the same seal as the front output. I then drilled and tapped the output shaft to take a 1-1/2" long 1/2" bolt and had to make a spacer so that the flange would bottom out on the bearing otherwise it would slide back and forth on the shaft and probably leak. I then cut down a factory front drive shaft and used it (scout with chevy drivetrain, my rear shaft is only like 21" long) with no vibrations up to 40-45mph or so.

I thrash on this thing pretty hard and haven't broke it yet but I constantly worry about it blowing the bolt out of the end of the output shaft. I don't know what the likely hood of it actually happening and like I said it hasn't happened yet but I worry about it. Im watching craigslist for something better to swap in with a bolt on style yoke but until then Im gonna keep pounding on my 208

As far as the factory slip yoke goes, I don't see you pulling it apart. Since its centered on the axle it doesn't travel much as the suspension articulates so it would really only move a lot if the suspension were to completely unload which would require leaving the ground. My truck I used to wheel had 56" rear spring and would use every bit of a 15" travel shock and I never once pulled the slip yoke apart.

Thanks so much for the info! Im still debating if I should just use a slip yoke. Its temporary until I do a doubler maybe in the winter. I dont plan on jumping my truck so maybe id be fine with a slip yoke?

 

[Blue85]

There used to be a website selling a yoke to do just what you describe (drivelinesuperstore.com?). The drawback is that you don't gain the extra driveshaft length that a full SYE gives you. With a steep driveline angle, even the splines in a standard slip shaft can bind up some. This will be even more important to consider when doing your doubler, as the driveshaft will get shorter again.

How much angle is in your U-joints now?

EDIT: I think there was some old trick where you put some kind of grease on the slip yoke splines and it keeps it from binding for a while.

 

[wetoolowdingbangow]

There used to be a website selling a yoke to do just what you describe (drivelinesuperstore.com?). The drawback is that you don't gain the extra driveshaft length that a full SYE gives you. With a steep driveline angle, even the splines in a standard slip shaft can bind up some. This will be even more important to consider when doing your doubler, as the driveshaft will get shorter again.

How much angle is in your U-joints now?

EDIT: I think there was some old trick where you put some kind of grease on the slip yoke splines and it keeps it from binding for a while.

Correct that website has them but his reviews are horrendous. Up to 7 weeks to get a shaft from him apparently. My nearest driveline shop has a 2 day turn around and theyll make the flanged sye to go with the driveshaft.

Ah I see now how the shaft angle will be steeper then the real sye kit. I currently have the conventional 2 joint slip yoke shaft now. Its too short to use and when the correct pinion angle is set (perches not welded yet) the shaft binds on the yoke ears. I think the cv shaft im looking at works up to 30 degrees. ill have to measure where im at now.