New Noise after Rear Half Shaft / CV Axle Replacement

[ryanmcgrim]

Hello All,

I just recently finished a swap out of the rear driver CV / Half shaft on my 04 XC70. I didn't find much information online, so I decided to do a writeup on the procedure I use to do it. You can read about it here:https://www.matthewsvolvosite.com/forums ... =9&t=73507

I recognized that pretty much the only point where things can go wrong is if you are rough with the final drive / don't support it and damage your propeller shaft / joint, so I made sure to take a great deal of care to support the final drive and be careful not to damage the propeller shaft.

Now that everything is buttoned up, I am getting a whining noise that is connected to wheel speed, that goes away as soon as I accelerate, but starts making noise when I am coasting or decelerating (not related to braking). If I tap the gas again, it goes away until letting off the gas and allowing a deceleration / coasting.

I replaced the fluid in the most rear part of the differential, and believe that I added back the correct amount of fluid, but I am not 100% on that.

My plan is to jack up all 4 corners and let idle to see if I can locate the noise. My thought is that despite my care, the propeller shaft or coupling got damaged during the install of the rear CV halfshaft, but I am hoping not! I'm also thinking an incorrect rear differential fluid level might be the cause, but can't tell for sure.

Could you folks chime in to let me know if my thinking is correct, and what the issue might be?

Thanks so much!!!


Ryan

[xHeart]

How old are the wheel hub bearings?

[ryanmcgrim]

All four wheel hub's / bearings have been replaced within the last 30K or so. No up and down play on any of the wheels.

I got the car on 4 jack stands and noticed 2 things. The first was that the differential side of the newly replaced driver side rear half shaft had come loose out of the differential. The axle was not a volvo, and seems just a tad shorter, within a quarter inch or so, but I thought nothing of it. At first, when I replaced the axle bolt, it could not reach the threads of the rear halfshaft, so I did have to pull it in just a tad to get it to start threading. At that point it must have pulled from the differential. I did the axle bolt again to the VADIS 50 NM then went back under the differential, removed the final drive cover and used a draft and hammer to push it back into the differential. It's a slightly different axle, so I can't tell by looking at the passenger side rear if it's in all the way. Either way it's not going in any more. I just can't tell if the snap ring is engaged or not. I was careful to clean all dirt, dust and debris from the splines so I can't for the life of me figure out what is going on. Either way, it does feel like it's in pretty good.

After doing all that, I assumed the the problem must be resolved, and the noise cured, but that was not the case. With the car up on 4 jack stands I revved the engine and let the rpms drop on their own to mimic coasting. The noise (a griding, whiring, wheel speed based noise that sounds pretty bad) was still present. I narrowed it down to the front of the car. I had a friend rev the engine with me looking at the bevel gear coupling. The noise did not appear to come from here. The only odd thing I noticed was at no point did the propeller shaft engage. Meaning at no point did the rear wheels spin. IS this normal?

Finally moving on to track the noise, it seemed like my front driver side Axle was not moving uniformly, It was a bit wonky and making noise. It appears that this noise is coming from my FRONT driver half shaft. It seems so weird that this would happen right after doing the rear half shaft. It's also weird that the noise doesn't seem to have any connection with hard turning. Only with coasting or deceleration (any time the accelerator is not engaged).

Is any of this making any sense at all?

[ryanmcgrim]

I took a video of the sound, you can hear rotor noise, as there is a slight amount of surface rust, but the grinding / whiring can be heard the best right after an acceleration. This does not sound like any other cv joint / axle I've had. It sounds transmission related (like when a car is going in reverse, but with some grinding), but it sounds like it is coming from the driver CV.

I am really confused about this entire situation, especially since it only happens while coasting or decelerating. Any help would be appreciated!!!

Here is a link to the video:

[ryanmcgrim]

Well, the more and more I crawled around trying to pinpoint the noise, the more it sounded like it was coming from the angle gear, so I decided to bite the bullet and begin the process of removing the angle gear for inspection.

So far I've gotten the passenger CV axle out, the 6 allen/hex bolts holding the propeller shaft to the angle gear flange and the angle gear itself. Unfortunately, I can't seem to separate the propeller shaft coupler from the angle gear flange. Is there a trick to this? On a side note, it looks like my angle gear has been leaking for some time, and what I can tell of the collar and angle gear splines they both seem wrecked. Ill get a better look if I can ever separate the angle gear from the propeller shaft though.

Please let me know if there is any sort of trick to it,

Thanks!