4L60e Problems. Vibration and power loss?
02-07-2011, 01:20 AM
#1
4L60e Problems. Vibration and power loss? Im having some issues with power loss, as well as a pretty serious vibe. Ill try to be as detailed as possible on this.
My old setup:
Lid, Descreened MAF, Ported TB, Stock LS6 Intake, TSP 224R, 918s, stock exhaust manifolds/cats, SLP Y-pipe, Loudmouth, Powerbond U/D pulley, stock flexplate, Performabuilt 4k stall, Level 2 4L60e, 3.73s.
When it was getting tuned, it only made 349rwhp/352rwtq on the first pass, then pulled lower and lower on the later runs. I dropped a valve a couple weeks later. Fluid level was good, clean and clear, no burned smell.
New setup:
Lid, stock MAF, ported TB, Stock LS6 intake, FMS 30# Injectors, AFR 205s (63cc), AFR 224/228, Cometics, low mileage stock shortblock, U/D Pulley, stock exhaust manifolds/cats, SLP Y-pipe, Loudmouth, stock flexplate, Performabuilt 4k stall, Level 2 4L60e, 3.73s, Poly engine/trans mount.
Back to the same tuner, in cooler weather, and i made 5 LESS rwhp with more mods. My tuner guessed i should be making 370+ hp with these mods. Fluid level is good, clean and clear, unburned.
Im also getting slight vibrations all throughout the gears, but specifically 3rd gear gets REALLY bad! Its been there since i installed the trans. Im not saying for sure it is the trans/converter, since the trans mount was broken prior to installing this setup. It feels like the driveshaft is way off balance, but once it shifts into 4th its gone again. I know the poly mounts have something to do with the light vibes, but why is 1st, 2nd, and 4th ok when 3rd is terrible?
One last thing is on the way home from the tuner, I would give it throttle and bring the RPMs up, and hold them, and then it would feel like something would grab and the RPMs would come back down.
Where should i start looking? ALL help and input is appreciated!!
My old setup:
Lid, Descreened MAF, Ported TB, Stock LS6 Intake, TSP 224R, 918s, stock exhaust manifolds/cats, SLP Y-pipe, Loudmouth, Powerbond U/D pulley, stock flexplate, Performabuilt 4k stall, Level 2 4L60e, 3.73s.
When it was getting tuned, it only made 349rwhp/352rwtq on the first pass, then pulled lower and lower on the later runs. I dropped a valve a couple weeks later. Fluid level was good, clean and clear, no burned smell.
New setup:
Lid, stock MAF, ported TB, Stock LS6 intake, FMS 30# Injectors, AFR 205s (63cc), AFR 224/228, Cometics, low mileage stock shortblock, U/D Pulley, stock exhaust manifolds/cats, SLP Y-pipe, Loudmouth, stock flexplate, Performabuilt 4k stall, Level 2 4L60e, 3.73s, Poly engine/trans mount.
Back to the same tuner, in cooler weather, and i made 5 LESS rwhp with more mods. My tuner guessed i should be making 370+ hp with these mods. Fluid level is good, clean and clear, unburned.
Im also getting slight vibrations all throughout the gears, but specifically 3rd gear gets REALLY bad! Its been there since i installed the trans. Im not saying for sure it is the trans/converter, since the trans mount was broken prior to installing this setup. It feels like the driveshaft is way off balance, but once it shifts into 4th its gone again. I know the poly mounts have something to do with the light vibes, but why is 1st, 2nd, and 4th ok when 3rd is terrible?
One last thing is on the way home from the tuner, I would give it throttle and bring the RPMs up, and hold them, and then it would feel like something would grab and the RPMs would come back down.
Where should i start looking? ALL help and input is appreciated!!
Last edited by NVR_SPDS; 02-07-2011 at 01:54 AM.
02-07-2011, 08:13 AM
#2
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3rd gear is, in theory, a direct 1-to-1 gear ratio, so you will feel more vibrations in 3rd. Mine does that sometimes. The only thing I can think of might be the 3-4 clutch pack might be starting to slip some.
The RPM rise and fall is probably because of the torque converter being unlocked and then locking back up. If your tuner deleted TCC PWM then it will feel like a grab.
The RPM rise and fall is probably because of the torque converter being unlocked and then locking back up. If your tuner deleted TCC PWM then it will feel like a grab.
02-07-2011, 10:43 AM
#3
IMO the vibration in 3rd is from a beast sunshell with it's stock plastic thrust washer and loose endplay. End play needs to be tighter than stock.
When you balance a sunshell and modify it for use with torrington bearings and run the endplay tighter this is never a problem.
Next time you're driving and it feels like something grabs and the rpm comes down, tap the brake and see if the rpm goes back up for a few seconds then comes back down again. If it responds to this, then it's the converter locking up. You could call your tuner and ask him what the lock up speed is.
When you balance a sunshell and modify it for use with torrington bearings and run the endplay tighter this is never a problem.
Next time you're driving and it feels like something grabs and the rpm comes down, tap the brake and see if the rpm goes back up for a few seconds then comes back down again. If it responds to this, then it's the converter locking up. You could call your tuner and ask him what the lock up speed is.
