Driveshaft Angle

[Avs_Fan]

RE: Re: RE: Re: RE: Dont buy gas on september 3rd!

First time post. You guys have a great website with a lot of info, keep up the good work. Anyway I am a new Jeep owner, we bought a 1981 CJ5, and am having a great time with it. Also working on it a lot, but that is fun too. Found that there was little attatching the engine to the rest of the Jeep, replaced the motor mounts and transmission mount. Now there is a major shake when the Jeep is under load. A friend of mine, who is a mechanic, said that the u-joints would probably be the next thing to go. The u-joints seem bad, but he suggested that I check the angle of the driveshaft before I spent too much time and effort changing the u-joints and yolks. Most of the movement is between the endcaps of the u-joints and the yolks, although it seems like the yolks look fine, maybe the endcaps are just worn? What should I look for, what should the angle be, how do I measure it? Plus any other suggestions you might have for this novice Jeep owner. Thank you in advance for any advice. PS. The Jeep has a slight (not sure how much) shackle lift with 31" tires.

 

[Junkpile]

The angle between the driveshaft and the transfer case output should be equal to the angle between the driveshaft and the pinion. They don't have to be exact. A couple of degrees difference is okay. I like to point the pinion down a degree or two from where it should be, just to compensate for the small amount of springwrap you will get under acceleration, even during normal driving.

There are Tcase drop kits and spring pad wedges that you can use to help correct any mismatched angles.

 

[LBR]

RE: Posting Pics

I just got done measuring my transfer case yoke angle and welding up new spring perches to get the equal angles this weekend - the transfer case yoke angle was 4 degrees downward and after proper setup of the rearend ended up with 5 degrees yoke angle upward - close 'nuf for me. With an inexpensive angle gauge that measures and adjusts in 1 degree increments and the DS taken out, measure the angle of the transfer case yoke (hopefully downward). Then measure the angle of the pinion yoke (hopefully upward). Bear in mind that the Jeep needs all of it's weight resting on the 4 tires as it normally will (or set up the chassis and rearend to "make it think it's on all fours" like I had to do). As JP mentioned above, try to get the 2 angles as close to the same as possible to keep the u-joints in proper phasing. On the short CJ-5, I like to fudge angles in the direction to reduce the DS angle, whereas JP prefers to angle the pinion the other direction when need-be to aid in spring wrap-up. I agree and practice that theory in a vehicle with a "normal" length DS, but a CJ-5's DS is sooooo short that I rather reduce the angle from perfect instead of making it greater. So, compare the 2 angle measurements and use approved methods to get those 2 angles close to the same. LBR

 

[LVRockCrawler]

RE: Re: Holy fender overkill Batman!!

you can find shims in varying degrees to compensate... you dont need to weld up new perches or shackle mounts to correct... just insert the shims b/w the perches and spring pack... could be your ujoints are the cause but considering you have a shackle lift (throws off angles) double check the angles after changing them out (inspect your yokes carefully to make sure they're not wallowed out and it is the caps causing the looseness...) just my $.02 ....
and WELCOME!!! you've found a real friendly (not - condescending(sp?) place to ask questions) here!!!!

 

[Avs_Fan]

Thank you for all of the great information, but I still have some questions... I understand that the transfer case and pinion need to be within 4 degrees of each other. But, as LBR said the DS is so short and the transfer case and pinion are so close together that the angle between the two can get pretty steep in a hurry. I like the idea of compensating for the springwrap. My other question is do you guys think that I am barking up the right tree with this vibration or should I be looking somewhere else entirely? I think the u-joints need to be done regardless, but not sure if I need to be spending all of this time on the angle if it is fine. Thank you again for your reponses, I am learning a ton.

 

[LVRockCrawler]

Warning to all 50+

a cheap gage can verify the angles... if they're close enuff then just swap out the joints (can make a WORLD of difference) and then decide what level of vibration is "tolerable" - i get a little from the front shaft but nothing i would consider destructive (see the recent exploding NP231 post)... keep reading... great advice and ideas here!

 

[Bounty__Hunter]

Re: RE: What President Bush

The shackle lift shouldn't throw the pinion angle off too much, I'd change all the ujoints out and call it good enough.