I was driving my 2005 M6 Z51 today at around 35mph in fifth gear when something happened. When I went to pass the slow person in font of me, as soon as a second lane became available, I shifted down to third (no rev. match... oops), let out the clutch (quickly), got on the gas, and nothing happened but a loud clunking noise and the motor revving. The noise sounds very similar to the noises in the video mentioned in this post http://forums.corvetteforum.com/show...post1565125643. The noise doesn’t occur in neutral, but does happen at least in first and reverse, and seems to increase slightly (not directly) with engine RPM. The engine sounds fine but the drive train won’t engage (it very slightly does in reverse but then stops). Any clue as to what the problem is, clutch, transmission, other?

Update: I had the car towed home and immediately put it up on the jack. The noise was coming from the driver’s side axel slapping around in the wheel. It seems this was caused by a loose axel nut. My problems looks pretty much like what is seen here http://forums.corvetteforum.com/show....php?t=1544932. If anyone has a how to on fixing this or at least the minimum parts list that would be great.


---Matthew Hicks

 

05s have pinner diameter axle shafts and a known issue. Replace them with C5 or later C6 axle asms and be done with it.

Phil

 

I couldn't find an axle assembly later than 2005 at gmpartsdirect. Where is a good place to buy later axle assemblies? Will they fit in a 2005 without modification? I broke the splined part that goes into the hub not the axle itself (I will post pictures later), so the axle itself wasn't the problem.


---Matthew Hicks

 

Here are pictures of the axle.




Notice the crack just below the break, on the left side




You'd think a sports car wouldn't have these sorts of problems. Color me disappointed.


---Matthew Hicks

 

I'd venture to say this damage wasn't incurred from what you said. Probably the damage happened under some severe useage, then just happened to let go later.

 

Could be, I just bought it about a month ago. What would you (or anyone) consider possible causes? I would like this to not happen again.



---Matthew Hicks

 

Loose axle nuts.

 

That's what I thought it was, especially since my car is covered under the TSB concerning axle nuts.


---Matthew Hicks

 

Wheel hop by previous owner perhaps. Wheel hop is very bad for diff and axles.

 

This happend to me 2 weeks ago. Exactly the same downshift to 3rd. Loose axle nut, broken RT shaft. The stealership had mine in stock...Lol..There is now a stronger axle that is going in as replacement under warranty. Its the same as the 08 LS3 and 08 Z06. It was under warranty.

 

That damage was caused by the tensile stress from the nut being TQ'ed too tight. Forget the loose nut theory. I had the issue 2 times with a overzealous mechanic with a breaker bar bragging that the nuts will never come loose after he tightens them. It pulls the end out while the inside of the axle is pressing against the hub....it effect stretching it.

Get a C5 axle and put red lock-tite on the end and TQ it to 100ft pounds and let it dry. I snapped two of them in one week. The other side which was tightened by the same mechanic that didnt break, was on so tight that I broke a breaker bar (1/2 inch drive) trying to get it out. I went to sears where they all gathered round to see the wonder they had found and gave me a new one. I went back to the car and pulled up on the breaker bar with a pipe to extend it and the car came up off the jack stand. I heard a loud squeak as the nut let loose (with a cork comming out of a bottle sound) slowly and the car went back down.

Axles that break from severe punishing abuse at a track break on the inside of the joints where they are thinnest not inside the hub where the surface is turning with the entire end of the axle.

Mine broke in exactly the same place and the nut was welded on tight with lock-tite by the mechanic that overtightened them. In fact, the second one broke the night the first one was replacedby the same mechanic. It was a light hiway drive to go visit RJ (aintqik). I was towed to his house where he let me take his axle to get home. I got him a new one and replaced both of mine with C5 ones and did the lock-tite and 100ft pounds. A year and going strong. I have a spare for anyone who breaks down and needs a field swap to get the car home. I was so nervous that I kept the spare in the back with all the tools and a jack to swap it out on the street if I had to for about 3 months.

I posted this some time ago and still it persists that people think its from loose nuts. Mine werent anywhere near loose and it broke in the same spot. The GM memo telling you to tighten them to 130 will cause a break. Mine must have been like 200+. If the nut fell off there woldnt be a stretching effect on the end of the axle and you definitely would hear it rattling around.

 

Fred Beans and get the 2004 unit.

 

Good info Spin. Per the mechanic on mine, and unfortuanetly I didn`t see it to verify it, he said it was loose. But I can definetly see one being too tight doing as you describe.

 

It's obvious from the cup and cone nature of the fracture that, as previously mentioned, it was a tensile fracture. It looks to me like the tensile force from the overtorqued nut cracked it (in cup and cone fashion) and the torque of the downshift finished the job as shown by the twisted portion of the fracture. This failure gives pause to all of us who had been worried about undertorqued axle nuts in past months.

Thanks for sharing your experience with this lousy failure. I'm sure we will all be most careful from now on when checking for loose axle nuts.

 

I checked my vehicle service report and it appears that the left hub was replaced 10,000 miles ago. The mechanic could have over tightened the axle nut when putting it back together. I will be checking the other axle just in case.


---Matthew Hicks