Any ideas to why the rear u-joint in my duece roadster is not lasting more than 1000 miles. Just about 500 miles ago I installed a new u-joint from NAPA and greased it well and now tonight when shifting from reverse to drive it was giving a snapping/clunking sound, when returning back home I crawled under and could see by turning the aluminum drive shaft I could see about maybe a 1/16" play back and forth from the stationary differential yoke. I then checked the angle with a angle gauge off the drive shaft which read between 2.5 to 3 degrees. I know from my past hotrod building days and building drag cars a good rule is to have a little angle but not an excessive amount. I suppose I could make an adjustment to the upper 4-bar links to increase the angle, but am not sure how much angle to increase it to or if it would help at all. The ch***i and suspension is an older model TCI with triangulated four bar and coil overs on a 8" ford diff. The drive shaft is aluminum with good yokes as well as the ford's yoke. Any ideas or help would be apprciated to fixing this problem. I would like to take care of it in the next few weeks since I plan on running in the HOTROD MAGAZINE POWER TOUR the first week in June. Thanks, Mike M Grand Rapids, MI
when you install it, it will be real tight, just take a hammer and tap at he base of each ear holding the joint and it will free up and hopefully last like its supposed to. i know it doesnt make sense, but it works for me, my mom (old drag racer) taught me this trick. not bashing the ears, just tap em once or twice. try it and you will see what I mean. also, just a note to check, dunno on your hp or set up or anything like that, but are you getting insane twist on the diff? dont aim it higher at a static stance, aim the diff a smidgen (couple degrees) lower and under hard acceleration, the pinion will climb into a happy zone instead of climbing into a binding u-joint destroying zone so to speak, make sure its not climbing to far obviously. any of this gibberish make sense?
Thanks Chopped51 for being the first to reply, I was hoping to hear that and will hope to hear from others.
I have had numerous problems with napa joints as have others I know. I may catch hell for saying this but NAPA joints are garbage. A friend went through 4 in a mud truck and the last time we were at a run we had to make due without a new one, the cobbed together used one we found was installed with no grease and has held up for six months compared to the 10 minute napa ones. Get a good quality joint like a ****er and you should be fine.
i had a similar problem with my 8" rear and discovered i had the wrong u-joint in there....about 1/32 difference,but it was so slight i would have swarn it was the correct one.measured it exactly and told the driveline people...i had the wrong one!!! no problems since. the 2-3 degrees is fine,as long as the tailshaft of the trans is parallel to it.
I agree, you need more pinion angle....****** side, and at the rear end. Not enough angle will give you flat spots on the needle bearings and the u-joint will get real loose, real fast. Try setting the 4-link so it will have between 7 and 10 degrees. That should fix it. I would also raise the question to your Napa store that it didn't last but so long, maybe they'll comp you one, or give you some $$ back for labor.
According to Currie, “a street driven vehicle should strive for between 1 and 3 degrees between the transmission and driveshaft, and 1 to 3 degrees between the driveshaft and pinion. Furthermore, the two angles should be nearly equal (between 1 and 3 degrees), but always opposite.” Otherwise stated, ideally, the angles between the transmission output shaft and driveshaft, and between the driveshaft and the pinion will be equal and opposite and 3 degrees or less.
I would take it back and complain ! More than likely the thing was made in China ! Also make sure you have enough angle on the rear . Left , right , up or down , doesn't really matter but most go left or right . There has to be enough angle to put pressure on the needle bearings so that they turn . If not they will over heat and fail . That sounds like the problem !
I've seen every driveline angle rule in the book broken with 4x4s and still got better life than that. Take that shaft in to a shop and make sure it's not bent or has the cap welded on off-center. What are you using for straps at the diff? Maybe you've got mismatched straps and you're crushing the caps???? good luck
The angle of the driveshaft itself is kind of irrevelent . The pinion angle wants to be the same as the front yolk ( u-joints parallel ). This has always worked well for me and my customers, especially with a 4-link , where the pinion angle doesn't change with travel .The joints should have a few degrees in them .
I'd be checking the angle of both joints on the driveshaft as mj40's mentioned. And yes the angles need to be as close to the same as possible. Here's another vote for the ****er or Neapco U joints and make sure they are the ones with the long very thin needle bearings. Also I think that Napa has two lines of Ujoints and the lower price ones aren't too great.
Turboroadster, thanks to for your thoughts and yes I can make sense of your gibberish. When installing the new joints they are always tight but not any thing like tight binds and have always done a little of the tapping trick you mention which I learned from my heavy equipment and farm machinery repairing days and as for the power the sbc is maybe is pumping 400hp and from time to time do romp on it and sometimes hard. The rear suspension is fairly stiff so when the turbo 350 shifts hard you can feel the rear of the car drop down slightly, maybe a given of 1" if that. thanks again Mike M
I had a bent yoke on a Ford 9" that would do that. It was not obviously bent. Took a while to find it. NAPA has two qualitys of Ujoint. Make sure you are getting the better one. Your pinion angle sounds ok, as long as the front angle is the same.
lots of good points here. I 'm ***uming your driveshaft is phased correctly, and if your caps are a little too small , that thing will bang around and destroy itself quickly .And ALWAYS use an American made joint ( ****er ).
Thanks to all for the comments on the NAPA joints. The first two I installed which went bad (the needle bearings on both caps were completly discrintregrated when the caps were pulled off not one needle bearing was found and there was only metal particles mashed into what grease was left in them) Even one of the caps were cracked with a piece of it fall off. The first one was replaced by NAPA at no charge and since this one is now gone bad. The NAPA brand is called Precision Universal Joint (PN 249) by Federal Mogul Driveline Products and is printed on the box "Made in Chicago, IL USA". I have since purchased a Sever Duty joint of the same brand Precision Universal Joint from NAPA which is (PN 250) and it too says its made in the USA and of co**** it was nearly $50 cost with shipping cost. I will install this one and give it a try and in a few weeks of hard driving we will see if it holds up. If not then I will look into and consider other measures which each of you guy spoke about. Mike M
Don't let anyone tell you you're doing crazy things to that Ujoint that should shorten it's life to anywhere near that level. Those ****ers ought to last 50,000 miles at that power and weight and useage.
I think shifty may have hit on your problem the straps might be the wrong ones..too tight ran in to this on a project..had 4 straps and thought i had put the right ones back to where they belonged.. I found out i was wrong before any damage..
One other thing to consider.Is the rearend yoke centered in the housing or offset to one side. If offset that adds angle to the driveshaft in adition to any up/down angle. If that is the case you then are not running equal angles. At this point I think if the angles look OK I would take the shaft to a driveline shop to be checked. Phasing is only one thing that needs to be checked,the bores of the yokes also need to be parallel.
when I bought my old 49 chevy sedan the rear end was pointing 4 degrees down, and the trans was 3 degrees down. I'm sure this combo had more than 1000 miles on it before I got it, and the next weeked after I got it I drove 300+ miles round trip. then I drove it a couple more weeks before I got under it and saw how messed up it was. fixed the angle, inspected the joint, greased it and put it back in. I'd say you got ****py u-joints since a bad angle didn't destroy mine after who knows how many thousands of miles.
I agree with some of the other posts.I had the same problem in a 4x4 lifted truck.Too much pinion angle and also switched to ****er u-joints. My 56 Chevy in high school kept burning them up too because I was buying the cheapest GMB & other **** from Grand Auto & didnt know spending a few more dollars for a ****er in the long run would save me money and work and not pushing my car.
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