Vibration

[SAAAAAC]

So I have my 5 speed GM that some of you know about. I get a vibration in each gear at a certain rpm/mph. I don't have a tac at the moment so I can't give you the exact RPM for each gear. I have 4.10s installed. When in 5th gear reaching speeds of 110mph, it feels like the transmission wants to blow out of the car. But if you hang in there and go faster it will go away, although going faster makes me very nervous. But just cruising in 5th gear going around 65mph / 70 mph it has a slight vibration but anything in between 70 - 110 no vibration. 4th gear does it too around 45-55 mph. I'm wondering what could be the cause of the vibration. Rear gears? Drive shaft out of balance? Any ideas?

Thanks

[guspech750]

I'm going with the drive shaft. Since so many people have stated that after installing 4.10 and higher gears, the (stock) drive shaft begins to vibrate do to the increase in RPM's at higher speeds.

That's my thought and I'm sticking to it.


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Eaton Swap + 4.10's = Wreeeeeeeeeedom!!

[RF Overlord]

Rear gears? Drive shaft out of balance? Any ideas?Unlikely to be gears...I'm-a go with driveshaft...or a bad/binding u-joint...or something not lined up correctly in the clutch assembly...

Another thought...pinion angle change when the manual trans went in?

[SAAAAAC]

U - joints look good. Clutch assembly should be good we just redid all of that. If it were the pinion angle, don't you think it would be more consistent?

[SGT_MERC]

Does the vibration feel like it gets stronger then weaker, like a rhythm, while maintaining the same speed.

[mike P71]

I'd say you have to adjust the pinion angle. I had a similar problem in a mustang after installing an aluminum driveshaft. After adjusting the pinion angle the vibration went away. Good luck

[SAAAAAC]

no, just fades in then out as i go faster.


Does the vibration feel like it gets stronger then weaker, like a rhythm, while maintaining the same speed.

[SAAAAAC]

i'm going to investigate the pinion angle and I'll have the drive shaft balanaced.



I'd say you have to adjust the pinion angle. I had a similar problem in a mustang after installing an aluminum driveshaft. After adjusting the pinion angle the vibration went away. Good luck

[Green96]

Drive shaft should not come and go with each gear. Nothing after the transmission comes and goes with each gear. I say you have a trans problem or a motor balance problem that was masked by the damping of the torque converter before the swap.

[SAAAAAC]

interesting.....


Drive shaft should not come and go with each gear. Nothing after the transmission comes and goes with each gear. I say you have a trans problem or a motor balance problem that was masked by the damping of the torque converter before the swap.

[Marauderjack]

Drive shaft should not come and go with each gear. Nothing after the transmission comes and goes with each gear. I say you have a trans problem or a motor balance problem that was masked by the damping of the torque converter before the swap.

Are these motors externally balanced and if so it sounds to me like the wrong flywheel??:confused:

[Green96]

Are these motors externally balanced and if so it sounds to me like the wrong flywheel??:confused:

Could be, or bent. 110 is about where the drive shaft critical speed should be with 4.10s. This could be adding to whatever else you have going on in each gear to make it feel even more intense at that particular speed. I would be careful going faster to get rid of it. The drive shaft is at it's limit. Did you have to add a harmonic balancer when you added the manual trans? I really do not know much about the swap, just trying to talk thru the issue logically ruling things out.

[Green96]

Never mind.