2008 Chev Silverado with clunk - POST FIX

Posted yesterday about a clunk when shifting between drive / neutral / reverse. I had mentioned that the universal joint seemed tight when pushing/pulling on the driveshaft. Well, I crawled back under the pickup today with an small screwdriver this time and pulled the grease seals back. Some of the needles were already gone. Some were at angles causing the bearing to seem tight. So, it was the universal joint fortunately and not the differential. Thanks for all of the responses.

And that vibration you had when you accelerated is gone that you failed to mention.

Did your. U joint hqve two different size bearing caps? My 06 wt did, was kind of weird got the wrong one from napa, was kind of odd.

I never could understand why some of them had two sizes of bearing caps. Seems like it would drive up the cost of the U joint.

Fixerupper, the reason for the different size bearing caps, called an "offset" joint is actually a cost
reducing tactic.

There are many combinations of transmission/drive shaft/rear axle options. Instead of having to make a
specific drive shaft for each combo, it is more cost efficient to use one universal drive shaft, and many
combinations of u joint crosses.

One other benefit is it comes in handy to be able to buy offset u joint crosses when making changes to a
vehicle, as in repowering, adapting a different rear axle, transmission, etc.

Yes, the vibration went away. With some of the needles out of the bearing, the driveshaft really didn't center with the differential yoke properly. The driveshaft was a little off center. All is well.

AMAZING how sometimes the most obvious, easy, and lowest cost fix possible can solve a problem.

Some of the replies your other post sure spewed doom and gloom!

I'll second that one! :lol:

Yep.

A foot note. If there was Locktite on the threads of the u-joint cap straps, make sure you use it when reinstalling. The caps can come out.

(quoted from post at 09:43:09 04/07/16) Yes, the vibration went away. With some of the needles out of the bearing, the driveshaft really didn't center with the differential yoke properly. The driveshaft was a little off center. All is well.

Click to expand...

Put that one in your bag of tricks.

A defective U-joint will give a vibration when under a load the vibration will go away when not under a load. The vibration my be a stile buzz feel are a harsh rumble. Joints that are froze up are the hardest to diagnosis from the drivers set feel because a u-joint test is normal confirmed by a hard acceleration anytime in the drive cycle. A locked up joint gives a site buzz feel under lite acceleration it worst at slower speeds (around 30MPH) you would think its inherent to the vehicle...

One of the best mechanics I ever knew gave me this tip 40 years ago it has served me well...

Hey Bob
Have you never been asked over the phone what a problem can be, and said well on the cheap side it might be it needs greasing ,oil or a new U'J . On the expensive side the axle or something in the drive line could be piling up. If a guy asked me that's the options he gets without seeing/hearing it it,we then go look or the guy does it himself and cuts me out. Thats what advice these guys gave from their various different experiences.

Put it like this as for forum answers given, and what you just said. If you are 100% right every time I'll pay you to stay home and diagnose every problem over the phone,when guys call. I can pay you $40 for diagnoses without leaving the yard. Then go fix the problem on the guys property with all the parts first time and still make good money for doing the work. I would have the ultimate business everybody wanted to use. I might even need to take on 10 guys to keep up. I have been fixing quite a few years and every once in a while, something you have fixed 30 times with the same symptoms, might not be the actual issue when you get there. Lifes not that easy sometimes from a guys description of a noise or problem.
Regards Robert

Mr. Major I am 100% with you, It's impossible to be RIGHT all the time.

On the other hand, bad/worn/dirty/dry U-joint crosses/bearings at the rear axle pinion are so ubiquitous and CHEAP ($15) how could you NOT try that first vs. a $3000 rear axle job?

Some 'ol fellow a long time ago had the same opinion.

WHERE would you start... the $15 cross kit or the 3000+ rear end job?
The RAZOR

Hi Bob I'd personally start with looking at it properly like The op did in the end for a proper diagnosis if i got chance to see it. As we both know there are many parts get thrown at projects from comments made by guys on this very forum,and some others to in the world that want a cheap fix without paying for a mechanic. I know a guy had a charge issue with a tractor.

The town parts guy told him change the alternator, he did that and still nothing. next they changed 2 battery's guess what!. I happened to know this guy as a customer from a few years before. But he didn't want to pay me or anybody to fix it, trying to be cheap so he never called anyone other than the parts guy that was wildly way off guessing with no diagnosis.

I was in town for parts and listening to the guy and this problem. I just said yeah thats a black wire in a 4 pin plug in the dash melted and thats whats wrong.I called there on the way home went right to the plug, rejoined the bad wire. guess what it fired up and charged!. the guy spent $500 on stuff he never needed.

He asked what that fix cost I said nothing you're already $500 in a hole you didn't need to dig, just call me next time you are thinking about chucking parts at a job, it might be cheaper in the end. I have been out there at least twice more for problems he spent money on and didn't fix himself. I just smile now when I print his bill out, say thank you when he pays it,and shake my head on the way to the bank.
Regards Robert

Thanks for the follow-up. It's always good to know what the end result was.