ThoR294

iTrader: (6)

So, long story short, I have been chasing a god damn vibration for over 2 years in this god damn car. I have seriously replaced everything brand new except for the transmission.

I have the OE trans in it currently with 115k miles, and I have a wicked vibration over 70mph.

The vibration is noticeable with the car in gear and cruising... but as soon as I push the clutch pedal in... it gets way bad. same thing if i put it into neutral. As soon as i get below 70mph it vanishes.

I have had my wheels straightened, new tires. same vibration

took an alum driveshaft from a 01 camaro, new ujoints, vibration went down a little bit... but not much (i guess alum dampened the vibration)

had my OE steel shaft balanced with new u joints... same vibration

Found my Torque Arm was cracked, so I replaced it along with a relocation xmember... set the pinon angle to -2. same vibration.

Had my rear completely rebuilt (minus posi unit and axles)... same vibration. (axles are straight)




When I did the clutch, I decided to put the ebay transmission i got 3 years ago into the car. I dont remember when the vibration started either.

so I put the OE trans back in, same vibration.

I DONT KNOW WHAT IS WRONG. So what I want to do is check the ebay transmission and see what could possibly cause this. I am at wits end, please help


I grabbed the yoke on the d/s in the car and wiggled it a little bit up and down... there is slight movement... I guess thats the output shaft bearing? or the bushing?

bigj2717

iTrader: (15)

If the vibration is there with both transmissions then it could be the flywheel and clutch is not balanced

ThoR294

iTrader: (6)

car is in neutral, engine off... vibration is still present, no change.

z28camaro1996

iTrader: (1)

mine was doing that and my torque arm bushing was bad.

ThoR294

iTrader: (6)

i have a brand new torque arm

z28camaro1996

iTrader: (1)

did you replace the bushing too?

99ssleeper

iTrader: (98)

I think you found the problem.

cam

iTrader: (9)

Try another set of wheels from a friend or fellow members car that drives smooth. 9/10 mystery vibrations come from the wheels. Its very unlikely that theres anything inside the transmission loose enough to vibrate the car that lasts more than two days let alone years so I cant see it. Its something else thats not affected by the vibration or it would puke. If it was the diff it wouldnt last after a while and it would get worse and worse until blam. Thats why Im suggesting the tire/wheel combo is the most likely problem and the easiest to sort out. Plus its often the problem for anyones vibration.

Very hard to diagnose these kinds of problem without driving the car. Good luck

ThoR294

iTrader: (6)

yes it came with a new vibration.








how could it be the wheels if it changes when the clutch pedal is engaged or the car is placed into neutral. etc. I roadforced the wheels and measured the runout.. all within spec

z28camaro1996

iTrader: (1)

well i took a little cruze to work today and noticed that my vibration is still there to but now i really only feel it through the shifter and the clutch petal. and it also feels like its right beside me.

cam

iTrader: (9)

So if I understand correctly the vibration happens when the car is sitting still?

zman1969

iTrader: (91)

thor294 sounds like a real *** whippin, as stated above I dont see anything in the trans that would do this. You've done alot of comparisons- old Vs.new d/s, trans, tires, wheels so iwould rule them out and start looking at things yet not looked at- driveshaft angles? pilot bearing? motor hitting on the body? motor mounts? I used to own a 69 Z/28(still do just a different one) and it had a over 70 mph that got worse the faster you went- never figured it out but the only thing I never swaped out or really looked at was the differential and driveline angles. I rarely drove that fast w/o overdrive and 3.73's. hope these suggestions help to think about other things - the it gets worse in neutral or when clutch pedal is pushed down leads me to think definate drivetrain just not the trans-the output shaft will wobble a little on any trans the bushing in the tailshaft stabilizes the shaft talk or have a master tech ride in it and show them what its doing at that level most are pretty analytical in thinking- good luck

wrd1972

iTrader: (12)

I feel your pain. Every time I think I have driveline vibe whipped I either become temporarily numb to them or they return.

First off I had a wicked vibration at any speed when the clutch pedal was pressed. It was accompanied by a growl and vibe in the seat and shifter. Absolutely no vibe or issue when the clutch is NOT pushed in. The cause was a heavily worn pilot bushing. I replaced the bushing and all of that mess was 100% totally gone.

Now I have a chromeloy DS that has a tiny harmonic at 75-80MPH. It does it mostly coasting down hill and less so under load going up hill. I can feel it in the seat and slightly in the shifter. At 80MPH in 6th gear, I hear a ooooom,oooooooooom,ooooooom about once per second. This feels an awful lot like the funky harmonic I had when the car was new and the DS was replaced with a 1LE DS under warranty. At 80 MPH and I shift to 5th, I hear and feel ooom,ooom,ooom,ooom,ooom about three times per second. Of course then I had the 3.42's so the problem happened at much higher speed than with my 4.10's I have now. With this harmonic, the car is very drivable but the harmonic is annoying. I had the DS balanced by PST and its dead nuts and my pinion angles are 1 degree opposite angles with the 9" rear end.

I also have an aluminum DS that was a wicked vibe at 75-80MPH. The floor vibrates as well as the shifter and it gets much worse if you push the clutch a coast. If I put the car on stands and have a buddy run the wheels to speed, you can get under the car and observe and feel the vibes going from the front of the DS or the rear of the tranny. This vibration is bad enough that I dont want to drive at 75-80MPH. I replaced the front u-joint and there was no improvement. I have sent the aluminum DS back to PST for re-balancing.

Considering I can take the chromoly shaft out which has a very minor harmonic and put the aluminum one in and get wicked vibes. There must be a problem with the aluminum shaft.

No with both drive shafts, I have .025" of up and down play at the slip yoke where it slides into the tranny. My understanding is that some slop here is normal. What that amount is I do not know. I do not have any noticeable slop on the back of the tranny output shaft.

When I had the tranny out to replace the pilot bushing. I detected a small amount of slop on th input shaft but I did not measure it. I would guess at .020" - .025" of up and down slop but there is no noticeable end play or front to rear slop. I also inspected the input bearing and the main shaft front bearing and saw nothing unusual.

I am confident it is not the motor because I can coast, kill the motor and the vibe remains. It must be between the front of the tranny and the ring and pinion. The tiny harmonic can easily be affected or changed by slightly acceleration or decelerating so I dont see how it can be tires or wheels.

So I am now hoping that the aluminum DS is frigged and out of balance. I am then hoping it comes back balanced and once it is installed the small harmonic is gone in much the same way the harmoic was fixed several years ago with the aluminum 1LE DS by the dealer under warranty.

Again the highlights.
80 MPH/2K RPM in 6th, I hear oooooom,oooooooom,oooooooom about once per second.
80 MPH/3KRPM in 5th I hear ooom,ooom,ooom,ooom about three times per second.
80 MPH in 4th. Smooth as silk.
4th gear at 2K RPM. Smooth as silk.
4th gear at 3K RPM. Smooth as silk.
Harmonics are only in 5th and 6th gears.
Clutch it at 80 MPH. Smooth as silk.
Rev the motor at 80, clutch in, to 2-3K RPM. Smooth as silk.
Cant be the tires or wheels.
Cant see it being ring and pinion.
Not the u-joint angles.
Not the u-joints.

Next things I am going to do:
Take the ASP underdrive pulleyoff and put the stocker back on.
Double check the tranny mount bottom nut for tightness.

ThoR294

iTrader: (6)

i meant new vibration by new bushing... i have a reloc xmember and it came with a poly bushing.

I have the pinion angle set at -2. The ds was at -1 and rear at -1.

My vibration is present at all times over 70mph, but it gets worse when u push the clutch pedal in or shift the trans into neutral.

I was thinking tailshaft bushing? IDK how to do it though in the trans... the zone has a outer seal and bushing for $10... worth a shot if I can find a write up

ThoR294

iTrader: (6)

no, its only over 70mph

z28camaro1996

iTrader: (1)

your vibration sounds alot like mine.but some times i can shift up or down and feel it only at high rpms two

Tx91z28

i have the EXACT same issue w/ a lt1 t56 behind my sbc. i have replaced wheels, tires, rear end, driveshaft, all bushings, nothing changed it.

right at about 70mph it starts vibrating badly and gets really bad when i push the clutch in. i'm convinced we have clutch or transmission issues, my trans/clutch is started to get loud and make some bad noise as of recent. i wont drive mine again until i get it sorted out because i feel like i'm hurting the drivetrain when i drive it

ThoR294

iTrader: (6)

Im so annoyed... I just want to get money for a PST new aluminum driveshaft and get my trans rebuilt my tick... hahaha. Lottery please...

anyway, does anyone have a write up to do that tail shaft bushing while the transmission is in the car?

jmd

iTrader: (4)

See my post here:

https://ls1tech.com/forums/manual-tr...g-trouble.html

I think it's sold as KD tool # 2200. It's meant to do a "small" output shaft bushing in-car.

ThoR294

iTrader: (6)

can that be done with the trans in the car?

that tool is ~$100???? ****