2004 Z71 - Bump in steering

Gus

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#16
Unfortunately, intermediate shafts have been a major problem for GM........

They tried the "lube" job.....then they replaced them with a new design....then they lubed the new design....then another design......this was on trucks, N and W bodies....never seen this problem on F, C and H cars.......

I don't know if it was the design or the manufacturing process.....normally, when you replace a part under warranty, you hold onto it for so many days before throwing them out, in case GM wants the part back......we had a huge box tagged with all these shafts......with the shaft out, you couldn't "feel" any problem with the shaft.....
 

ChevyDude

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#17
:mad:

Gotta love extended warranty companies. Their adjuster went out to look at the part today and denied the claim because the intermediate shaft had rust on it...is what I was told. I picked up my truck and the old shaft and evidently the minor part of the shaft has a little surface rust. From what I can tell, there is a plastic spline that is pressed onto the shaft end that closer to the gearbox. That plastic spline mates with the metal tube with the inner spline. There is absolutely ZERO rust inside of the spline. The surface rust he mentioned does not have anything that functions on that part of the shaft. Not taking this one all that well....will discuss with the warranty company tomorrow. It's quite obvious to me that they are looking for the easiest way out.
 

Attachments

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#19
U-Joints 101, if the shafts are perfectly axially aligned rotating the input say 180*, the output would rotate exactly 180*, but if this was the case, you wouldn't even need a U-Joint. But proportional to the angle of the shaft, the output degree rotation, can vary considerably with the input, but still 360* in will give 360* out.

Not only this characteristic, the length of the shaft also varies, so those splines have to be able to move in and out, which is the precise reason why splines have to be used in the first place. A simple cure would have been to clean those splines and well lubricate them.

A real cure for these kinds of problems is to use not one, but two U-Joints where the action of one, cancels out both the axially and radial variations of the other. Such is called a constant velocity joint. But with one joint, those splines have to be free to move in and out.

Nothing new here, just basics. The math gets kind of hairy when you have to calculate both the radial and axially variations based on the degree of changing the angle of the shaft. Three vector trig, x, y, and z axis.
 

ChevyDude

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#20
Thanks Nick. The u-joint is not in a bind...very free. The question is regarding the spline. If the inner spline does not have any rust, then how can the little surface rust on the minor portion of the shaft affect anything. No affect on form, fit, or function in my opinion.
 
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#21
No difference at all, not a contacting surface, my question and will put it as a question this time, is how freely does that spline move in and out. From your photo appears to be bone dry.

In machining, a 0.0001" difference makes a huge difference between a slide or an interference fit. First can be moved with your fingers, second takes a sledge hammer to put it in. A spline also has a wedging effect and really can bind.

In my dealings as an expert witness, most frustrating is dealing with mechanically/electronic uneducated people, like attorneys.
 

ChevyDude

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#22
Thank you sir!! Spent 30mins on the phone with a manger of the warranty company and for 15mins he insisted that the rust was affecting the ability for that shaft to slide into the internal spline....even after seeing my photos. Finally he consulted with another manager and after a 5min hold came back and immediately said "no problem, we will cover the claim". Amazing!!
 

ChevyDude

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#23
Just reading my old post regarding the intermediate shaft....depresses me to no end. Now at 71k miles, I strongly suspect the shaft needs replacing again. No mo extended warranty...on my own $$$$.

Any new and encouraging revelations with the intermediate shaft?

Thanks