MARBLES in TAILSHAFT.....

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pastortom1

pastortom1

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Guys........

I have a 727 Auto that was hooked to a driveshaft which was out of balance....it ate up some u-joints, and vibrated & made you crazy.....didn't drive it much.....I had a new shaft made and balanced, and installed it....Nice.....ALMOST all of the vibration is gone, but NOT quite......

Now, when the car is in Drive and downshifts smoothly at low speeds (around the village....allowing the car to shift itself), when you get to a low rpm in second, and it's ready to downshift into 1st, I hear "marbles" rattling around in my tailshaft......literally........that's the best comparison I could use.

Every time it shifts down at "no-load", I hear marbles.........like the teeth of a gear gently rubbing against something making a "rattling" sound.....

OK.......what's up? What in the world am I hearing, and could this be serious? I'm afraid that when the shaft was out out of whack that it ruined something in the tail shaft............:read2:
 
The noise is probably coming from the U joints again. I have to wonder about your center line and pinion angle since those factors determine the life of a U joint. Hopefully it is something simple like a joint didn't go together right. Gotta love those little needle bearings.
 
Well, she's up in the air right now so I guess I'll pull the shaft again and check the needles............

Anybody else with an opinion here? :read2:
 
i'm thinking Pinion angle...... it can cause vibration for sure.....
 
There are no problems at the pinion......pinion angle is near perfect.......I have not checked the rollers, but the u-joints seem nice and tight.....they're brand new and have less than 30 miles on them as it is.........I don't expect to find anything wrong inside the caps, but I'm going to check anyway.......

I've heard many a u-joint growl, and this does not seem at all like a u-joint.......Marbles....rattling around in a glass jar as you turn it, but as I said, not really randomly.....evenly timed like hearing the edge of a gear rattle aginst something......

Is there a particular bearing inside the tailshaft housing that could have been knocked silly when the shaft was so out of balance?......Both u-joints were bad at that time too, and the front was really sloppy......I'm wondering if it knocked the snot out of a bearing in there..........???

I'm NOT a tranny guy.........I need some expert input here...........
 
:( No more guesses from me. I'd have to hear the noise. Sooooo many thins that can make a come and go driveline noise. Loose torque coverter to flex plate bolt/s. Broken torque converter to front pump neck. Basicly from the engines thrust bearing back to wheel bearings. Best of luck with the hunt.
 
The noise is definitely inside the tailshaft housing.............whether traveling from a forward location, not sure.......but we've eliminated the driveshaft....the noise is clearly right under my shifter, and the shifter is directly over the housing..........

Is there a main bearing around the output shaft? Seems as though there must be something right there............
 
There is a bearing on the output shaft located in the tail housing. The vibration could have damaged the bearing. As mentioned above, I would also check the tailshaft bushing.
 
At least those 2 things can be changed without pulling the transmission, just the tailshaft housing.
 
There is a ball bearing on the tailshaft, and the parking gear and pawl is back there too. On the bottom there is a plate with Phillips screws. Inside it is a snap ring that needs to be expanded to remove the tailshaft after removing the attaching bolts to the main case. You'll then have access to the two, along with the governor.
 
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