5th gear vibration issue

[mazspeed]

Originally Posted by Blown353

Several things come to mind to check...

mismatched front to rear u-joint working angles

excessive u-joint working angles (this is the cause of my high speed vibration, I need to raise my entire tranny tunnel for more driveshaft clearance so I can raise both the tranny angle and rear end angle to minimize the total u-joint working angles.)

runout issues on either slip yoke or pinion yoke

worn & loose output shaft bushing in transmission

driveshaft runout / balance problem

If it's speed related and not RPM related as you said (the vibe occurs at a given speed no matter what the gear) that pretty rules out the clutch & flywheel as the problem and points to the driveshaft on back as the source of the problem.

It could also be a wheel, axle, or bearing problem too.

It's not speed related. in 4th gear at 85mph it doesn't vibrate at all. In 5th at the same speed it does vibrate. I have new wheels and I did watch them being balanced and they are lazer straight. Does the drive shaft spin more in 5th gear at the same speed as it would be in forth gear at the same given speed? I don't think that's the case, but I don't know.

[Vegas69]

It sounds like it's more rpm related. I would take the rpm you run in 5th at 85 and see if the same vibration is there in other gears at the same rpm. It could be a by product of the engine combination or harmonics through the mounts at that rpm. Could be the tranny but would exhaust other possibilities.

[kp.touring]

Hey guy's
Just to let you know the vibration is only in 5th. We have checked pinion angle and adjusted it, then ran the car at the same rpm as the vibration in the other 4 gears to rule out anything in front of transmission and then ran the car at the same mph in 4th gear to rule out evrything behind the transmission. The vibration is in the box.

Kevin

[kp.touring]

Just an update on Mike's transmission vibration. Keisler is going to repair his transmission under warrenty.

Kevin
CAR

[mazspeed]

Thanks Kevin for taking care of that for me. You guys do go that extra mile. Also thanks for taking to Hector at Rick's hotrods and for them to also fix my tank.

[awr68]

Sounds like the to-do list is getting much shorter!! Did we ever get the motor dialed in? And if so Dynoed? Where's my vid??

[mazspeed]

Originally Posted by awr68

Sounds like the to-do list is getting much shorter!! Did we ever get the motor dialed in? And if so Dynoed? Where's my vid??

Hey Anthony. The list is very small and it's being addressed right now. The tank is going back to Rick's for rebaffling, the tranny is going back to be addressed, the water injection was not shooting out much water at all. 5 tanks of gas, and it only went down one inch in the tank itself, and a 10 pound boost pully. And to fix the right side headlight door, that's pretty much it at this point. I have had a hard time getting a video camera.