CV Driveshaft question

[Critter]

This may be a dumb question...

Other than PRICE is there any downfall to having a rear drive shaft with a CV joint? In particular, I'm concerned with my 72 K5 with six inches worth of spring lift. It is mainly a street/trail rig so no heavy off roading is in store. Thanks.

[Oilbrnr]

Is your rear diff yoke pointed almost straight towards the TC?

-2* is about ideal so the grease gets worked around the u-joints. If it is way negative you could be inducing vibration.

This is a spring lift, not a shackle flip right?

[Critter]

Originally Posted by Oilbrnr

Is your rear diff yoke pointed almost straight towards the TC?

-2* is about ideal so the grease gets worked around the u-joints. If it is way negative you could be inducing vibration.

This is a spring lift, not a shackle flip right?

It is pointed slightly up, but not straight at the TC. It has new 6" lift springs (no shackle flip) and currently I have the original 12 Bolt in place with some 2* shims and thing seem to be OK. It might have had a little vibration to it, but very minimal. I have the blazer torn apart for a rebuild and will be going back with a 14 bolt. I figured now would be the time to do everything correct. So, starting with a "blank canvas" should I pay the cash and get a custom CV drive shaft built, or just incorporate the correct driveline angle into the pinion when I weld on the new spring perches??? I would rather spend the time and money now and do it right rather than later after everything is painted up and pretty. THANKS!

[Burt4x4]

Her is mine, 1350CV with Flange mount to the TC, so 4 bolts and the driveline drops off the TC.
ANYWAY.. I like the CV cuz you can point the diff straight at the TC for better pinnion trail clearance, true too much pinnion angle will cause lubrication issues so if you drive the Hwy speeds caution is needed. On the trail not somuch a concern. I ended up about 2* south of straight at the TCase for pre-axelwrap comming from my 454

[Oilbrnr]

Burt has a good point that I didn't think of RE clearance. But, and I'm no expert by any means, either you alter the perches to use the 'standard' u-joints or go the CV route assuming you are around -2*. Six-1, 1/2 dozen the other.

The CV route does add two additional wear items and will take more diligent chassis lubing than the non-CV approach, especially if it is more of a daily driver like my K5 is.

Either way, make sure that you get genuine Spicer parts. Some places will try and use off-shore joints.

[Critter]

Thanks guys. CV is the way I want to go, however it seems that most of the info/examples I can find using them are on an off road vehicle. I just want to make sure that there aren't any gremlins that will arise on a street machine at highway speeds. Sounds like the answer to that question is "no".

[Burt4x4]

If anything the CV will make for a better and smoother driveline. Good advice on Spicer brand..they make the best
I will never buy a non-cv shaft again.
Just my .02..oh and my K5 use to be a daily driver w/cv drivelines

[Critter]

Originally Posted by Burt4x4

If anything the CV will make for a better and smoother driveline. Good advice on Spicer brand..they make the best
I will never buy a non-cv shaft again.
Just my .02..oh and my K5 use to be a daily driver w/cv drivelines

That's what I want to hear. I agree about the Spicers, I already live by that rule. So, I guess I will point the pinion towards the tcase output and weld up the perches...actually I guess I will point it 2* down from that. Right???

[Oilbrnr]

Originally Posted by Critter

...actually I guess I will point it 2* down from that. Right???

Correct.

[Critter]

Originally Posted by Oilbrnr

Correct.

Thanks Oilbrnr! Last question. What is a fair price for a "custom" CV shaft? $300??? I don't want junk but at the same time I don't need the absolute top-of-the-line extreme offroad rock crawler edition.

[Oilbrnr]

Originally Posted by Critter

Thanks Oilbrnr! Last question. What is a fair price for a "custom" CV shaft? $300??? I don't want junk but at the same time I don't need the absolute top-of-the-line extreme offroad rock crawler edition.

Hmm, good question! I had front and rear drivelines done for ~$500 which included all new Spicers and lengthening both shafts, rear went to 3" tube up from the stock 2.5(?). That was back in March, and I finally got around to putting the CV on the rear last week. In the mean time, Dick's Driveline here in Phx. went belly up after 25 years, and their business was picked up by Phoenix Rack and Axle. Dick's wanted $150 + the cost of the new TC yoke. PR&A is charging me $265 with the new yoke/flange and seal. It is done now but I haven't picked it up yet but I will manana. I also have to pick up a 1 and 5/16" socket to get the TC yoke nut off.

[Oilbrnr]

Sorry for the hi-jack but it is CV joint related, and I'll edit this post with more info when I'm done with the job.

I am having a helluva time finding a 1 and 5/16th socket to fit the old yoke on the NP205! Have one on order with NAPA that will be in tomorrow, but if it is too big an external diameter, I may be forced to go to Snap-On.

The new yoke is even smaller internal (1.666" or ~1 5/8ths) diameter, and apparently needs a special thin walled nut. Not sure what the size of it is yet, but Phoenix Rack and Axle claims they have it. Hope I can find a socket that will fit that one next.

Are these special sockets or something?

I really need to get the old yoke off before driving 100 miles round trip, as there are three different yoke seals that could be used on the NP205. 80% chance that they gave me the correct one, but with my luck at this point, it is probably wrong.