Gear-dependent vibrations
04-09-2008, 10:19 AM
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Gear-dependent vibrations Background..
RPM-Stage IV T56,
LS6 clutch,
Alum. flywheel
stock driveshaft
4.10's
Poly bushings everywhere
u-joints are all tight and greased
gear setup is good and within specs
there is a little bit of play on the output, but nothing the gear guy said was concerning at all.
If I'm driving around 60 in 6th, I get a mild high-freq. vibe, can be felt mostly through my butt. If I drop to 5th, the vibe is gone at the same speed. This also happens in 5th around 40-45(Not 100% on the speed, but it's around there)
I'm very familiar with identifying speed-dependent vibs, but not usually gear-dependent ones..
Ideas?
RPM-Stage IV T56,
LS6 clutch,
Alum. flywheel
stock driveshaft
4.10's
Poly bushings everywhere
u-joints are all tight and greased
gear setup is good and within specs
there is a little bit of play on the output, but nothing the gear guy said was concerning at all.
If I'm driving around 60 in 6th, I get a mild high-freq. vibe, can be felt mostly through my butt. If I drop to 5th, the vibe is gone at the same speed. This also happens in 5th around 40-45(Not 100% on the speed, but it's around there)
I'm very familiar with identifying speed-dependent vibs, but not usually gear-dependent ones..
Ideas?
04-09-2008, 02:50 PM
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5th and 6th driven gears are both on a common spool-type gear. That is, 5th&6th driven gear is1 part with two gear cuttings on it. It may be that the spline & journnal this gear is pressed on to attach it to the main shaft may not have a tight fit (anymore). It could also be a simple as a bent mainshaft. If you have lost rear gears or a propshaft in past history, a bent mainshaft is quite commonly a secondary damage.
04-09-2008, 09:26 PM
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Fortunately, this trans was purchased straight from RPM, and there's been failures like the driveshaft or gears..
The PO drove it with a failing master & slave cylinder which caused other issues, so I'll have whatever shop I take it to (probably tick) look at 5th and 6th closely.. thanks.
The PO drove it with a failing master & slave cylinder which caused other issues, so I'll have whatever shop I take it to (probably tick) look at 5th and 6th closely.. thanks.
04-14-2008, 12:29 PM
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Paid more attention to it this weekend.. it'll do it in basically every gear at some speed...
I'd be kinda pissed if the mainshaft was bent from day 1...
I'd be kinda pissed if the mainshaft was bent from day 1...
04-14-2008, 08:10 PM
#5
If the vibration is RPM dependent (does it at the same rpm in every gear) then the cause is AHEAD of the transmission......meaning it's being caused by the clutch/flywheel assembly or the balance of the motor. Most likely your clutch/flywheel assembly needs balanced.
