02 Gt strange noise

07GtS197 · Nov 18, 2019

My poor 02 has been sitting for a bit since work is so damn busy but I just recently got it running again. One of the pulleys must have been stuck because when I first started it the belt was slipping and the alternator wasnt charging. A few revs took care of that lol. But now when I put it in 3rd and 5th (especially 5th) there is a grinding sound. Its not like a bad synchro grind, it engages fine and the clutch holds but it makes a pretty loud grinding sound kind of like a circular saw cutting a 2x4. I took a video so you guys could hear it firsthand. Anyone have any ideas of what it could be? Sticky starter maybe?

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lwarrior1016 · Nov 18, 2019

Can you pull the shifter bezel off and drive with that open to try to further locate it? That’s a wild sound lol. Any noise in 1st, and does it seem to pull alright in 3rd and 5th?

07GtS197 · Nov 18, 2019

I originally had the bezel off and it was a little louder but its still hard to tell where its coming from. It holds good in all gears and it doesnt make the noise in 1st, 2nd, 4th or reverse. Im thinking about changing the fluid soon anyway.

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07GtS197 · Nov 19, 2019

I drove it again today and noticed that when Im in 4th it doesnt make the sound but it will if I let off the gas and itll vibrate like the tires are off balance. As soon as I hit the gas it goes away. Maybe something to do with the input or output shaft? 4th gear is isolated from the rest of the gears, those are pretty much the only things they have in common. Also there is a bit of rotational play coming from the rear end. With the trans in 1st its a lot less but in neutral theres quite a bit maybe say 1/4 of an inch.

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07GtS197 · Dec 10, 2019

I finally got around to changing the fluid. The old fluid was brown and didnt even smell like atf. Im not sure how much came out either. I ended up putting in about 3.8 quarts of dex/merc after speaking with a tech at Hanlon. According to him they put anywhere from 3.5 to 4 quarts in with no problems. Welp the noise is still there... I dont think its internal transmission anymore, Im thinking maybe the clutch. What could cause a grinding noise with the clutch engaged but only in certain gears?

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07GtS197 · Dec 14, 2019

So after watching the video for the billionth time I realized something. It seems the noise starts in 2nd and is worst in 5th. It seems to be speed dependent not rpm dependent like I originally thought. If you listen closely it seems that each gear is a continuation of the noise in pitch. It sounds like rear end while but it doesn’t do it in 4th (only on decel) so I doubt thats it. It has to be in or around the tailshaft. Maybe the tailshaft yolk bearing? Some gears stress it certain ways and others the other way so thats why it happens under certain conditions. Any thoughts? Listen to it very carefully and tell me I’m not crazy lol.

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07GtS197 · Dec 15, 2019

Got it up on ramps today, it seems maybe the joint by the pumpkin is going. Also the driveshaft can move in and out of the transmission, not a lot but enough to where it seemed excessive. Is this normal? Im assuming no since the rear is bolted onto the pinion flange. Also I can move the transmission up a little and slightly twist it though it did take a bit of force. It seems there are a few issues but the noise itself I’m thinking is coming from the driveline whether it be the rear end, drive shaft or output shaft as it is speed and load dependant.

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Burninriverdiver · Dec 16, 2019

That’s a crazy noise, I wish I could help you out but I’ve never heard anything like that from my transmission.

How does the rear transmission mount look? The only thing I could think of is that the mount is completely snapped and the trans is shifting around when you change into certain gears causing the driveshaft to rub up against something. That’s the only thing I can picture making that kind of sound. Good luck and keep us posted

07GtS197 · Dec 16, 2019

The mount is in tact and and I looked all around for rubbing but couldnt find anything. I’m thinking maybe the transmission is shifting under load and causing the yoke to maybe wobble in the tail shaft but thats a stretch. I’m still curious if the driveshaft is supposed to move in and out of the transmission like that.

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07GtS197 · Dec 16, 2019

I got under it again earlier to get a quick video. This is the amount of movement with the shifter in neutral. Also note that it’ll slide back and forth. I couldn’t get a good steady video of it but you can see how the clean spot on the yoke gets bigger and smaller as it moves in and out of the tailshaft housing.

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lwarrior1016 · Dec 21, 2019

From the looks of that video, I think you have rear end problems or a u joint that’s trashed. The back and forth is what’s really concerning to me. Move that driveshaft like that again and see if the pinion flange on the rear end is moving in and out.

07GtS197 · Dec 21, 2019

I think it is. The car is low so even on ramps I can’t get too close to the rear end to really see it but it looks to me like the flange itself is moving. I’ll try again maybe today or next week.

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Adam Vinnicombe · Dec 24, 2019

07GtS197 said:
I got under it again earlier to get a quick video. This is the amount of movement with the shifter in neutral. Also note that it’ll slide back and forth. I couldn’t get a good steady video of it but you can see how the clean spot on the yoke gets bigger and smaller as it moves in and out of the tailshaft housing.

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Just to let you know my drive shaft does the same thing. Im running 4.10 gears but don't know if that will make a difference.

07GtS197 · Dec 25, 2019

Yours moves in and out? I don’t think its supposed to do that lol. But I guess it depends on where the slack is coming from. I haven’t been able to work on it but I’ll try to pinpoint it today.

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Adam Vinnicombe · Dec 25, 2019

Yep it moves in and out but not as much as yours. My stock one didn't but my aftermarket aluminium one does. I'm looking into way it does this now but have not come up with any thing yet. Please let me know if you find out why its doing it.
And merry Christmas

07GtS197 · Dec 25, 2019

Usually its the pinion nut from what I’ve read but usually it makes noise from the pinion moving and wearing the ring gear in another way then it was set up.

Merry Christmas to you too!

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lwarrior1016 · Dec 25, 2019

With the car sitting still like that, there should be no in and out movement. That means there is slack between the pinion bearings. The nut could be loose or the crush sleeve could be bad. Either of those is not good.

lwarrior1016 · Dec 25, 2019

There will be in and out movement as the suspension flexes going down the road, but that’s on the transmission side. Should be nothing sitti still.

07GtS197 · Dec 25, 2019

Thats what I’ve read I’ll just have to check where the movement is coming from. I have to get my hands on it first.

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07GtS197 · Dec 26, 2019

Finally able to get under it earlier. The u joint in the rear seemed bad until I realized the driveshaft bolts were loose! Wtf! The only 12 point anything I have were combo wrenches so I tightened them that way. No change unfortunately. It looks like I’m going to have to swap transmissions at this point. I still don’t buy its coming from the trans from the strange times it makes the sound but thats the last thing I can replace that makes sense. Good thing its a project...