Help! Driveshaft-car up in air apart dunno what to check next - Pontiac G8 Forum: G8 Forums - G8Board.com
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post #1 of 6 (permalink) Old 06-15-2019, 11:30 AM Thread Starter
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Help! Driveshaft-car up in air apart dunno what to check next

Carrier bearing bushing (Propeller bushing) holding up center of driveshaft was shot. There was a thumping right under front seats only during early accel. Cut off exhaust (bolts rusted, sigh). Could not figure out how the hell you get the driveshaft off the trans or the rear diff. Saw pics online that you leave the rubber isolators on the trans and diff and remove the driveshaft from those. Even with all nuts and bolts out, could not get either side of driveshaft out. Figured out I could remove the rear half of driveshaft if I unbolted the isolator from the diff and left it on the driveshaft. Front driveshaft I needed some kind of torx socket that I dont have but since the bearing is on the rear driveshaft I could leave it in. Top part of bushing was ripped, so confident that was the problem. Installed new OEM bearing/bushing. Reinstalled rear driveshaft and everything else. Celebrate for doing a PITA job on jackstands, feel like a real man.



On test drive, now there is a metal on metal grinding noise that goes faster and slower with driveshaft speed. Suddenly feel less like a man and more like a loser. Sigh. Trying to figure in my head the only thing what could make that noise, I start to wonder if the metal dust plate that slides on after the bearing/bushing unit was supposed to be tight against the bushing, and I left it loose and now its spinning loosely on the driveshaft? Thats the only thing I could think of.


Jack car up again, exhaust off again (at least it has new hardware now no rust) heat shield off again. I look at the dust shield and while it IS tight against the bushing, its spinning with the driveshaft. If I stick a broomstick in one wheel and put car in neutral, I spin the other wheel as fast as I can and the driveshaft is spinning but no noise. Argh so frustrating. No idea where noise is coming from, dont want to put car back together without checking everything because I know its still going to make that noise.


First question: this happen to anyone else? What should I check?


Second question: Is the dust shield supposed to somehow attach to bearing/bushing unit and not spin with driveshaft and thats my noise? Or is it supposed to spin around and just slide against the bushing shield?
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post #2 of 6 (permalink) Old 06-15-2019, 01:52 PM
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Here's the way I read the service manual. The 3 bolts (on each end of the driveshaft assembly) that are installed thru the rubber bushings an have their attaching nuts looking at the trans an rear gear assembly are the only ones that you remove. If they will not separate from the trans an rear end flanges, there must be some excessive stiction taking place at that location. They way the dust boot is clamped to the front half of the driveshaft, tells me *it* spins with the drive shaft. Along with that, they tell you what must/should be replaced along with the bearing assembly in that area (as in the parts that are considered a one time use item). I'll monitor your thread in case further info might help.
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post #3 of 6 (permalink) Old 06-15-2019, 05:17 PM Thread Starter
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The new bushing/bearing came with a new snap ring, oring, and dust boot. With the dust boot spinning right up against the bushing, I wonder if thats what making noise on mine. The dust boot does seem to wobble a little when I spin the tire to make the driveshaft move. I tried tapping it with a hammer to get it straight but its just less wobbly.
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post #4 of 6 (permalink) Old 06-15-2019, 07:09 PM
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The only other part (that is part of the bearing assy) is an item called the oil slinger. They say that is a one time use item also. So I guess that part came in the kit too. They show some type of tool is used to install that slinger, but unsure if really needed. So if its pressed into place (but yours isn't), maybe that can cause some type of noise. An of course they tell you its very important to reconnect the 2 driveshaft haves in their proper orientation, to avoid causing some level of imbalance.
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post #5 of 6 (permalink) Old 06-18-2019, 12:02 PM Thread Starter
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With car on jackstands, no exhaust, I had someone in the car letting the wheels spin at idle, 20mph, 40mph. No noise. (like I could hear anything under there)

With exhaust hanging by middle hangers almost dragging on ground, no heat shield: no noise

With heat shield and exhaust dragging: no noise

With exhaust fully installed, no noise.

So the noise went away by itself. I think maybe the driveshaft was hitting the exhaust after first install and was half an inch lower second time around? Exhaust is close to shaft, but I cant see any clean rubbings on it. Dunno why, but problem went away.
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post #6 of 6 (permalink) Old 06-18-2019, 01:15 PM
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Its nice that your problem solved itself. But with those darn PFM type of fixes, your just left with that thought of *what the heck just happened here*.
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