BADSZ28

iTrader: (39)

OK, I have been chasing a vibration for a year or so now. I just replaced the driveshaft and still have the vibration. It goes with the car speed and is independent of engine speed or gear selection or clutch engagement. It is pretty high frequency which leads me to believe it is not the wheels/tires or axles. Over the weekend I will try and get the car up and remove the driveshaft to watch the output shaft for out of round. It feels like it is coming from behind the front seats and under the car. Feels center of the car, not left or right. Any suggestions? I do not have the money to just take it to a shop. The rear has new gears and "rebuild" on it. No telling what parts were replaced when the gear was swapped. Experience tells me it is not a bearing since I would hear it all the time. I get the vibration at about 70+ most prominently.

Z28/2002

iTrader: (27)

Have you had the tires rebalanced to see if it stops?

connexion2005

iTrader: (49)

Ever changed gears or ran your car on good tires at the track? It's easy to throw the pinion angle off on these cars and basically an adjustable torque arm is the only way to get rid of it.

ManicMechanik

Yeah, if you can feel it in the steering, tires or struts probably.

SparkyJJO

iTrader: (11)

I have a vibration that I can feel through the steering. I just deal with it for now as it isn't too bad especially compared to my old car. Would like to figure it out at some point but it isn't high on my list of things to do.

BADSZ28

iTrader: (39)

I do not get it in the steering. I have a fixed TA so angle can not be changed manually or mistakenly. It would have to actually be bent. I do have adjustable LCAs and think that one may be shorter than the other. I will try making them even. Also, I have two other sets of rear wheels/tires. I will try swapping out a pair and see if that helps, but I really don't think it is that.

DRGnFLYZ28

What gear ratio and driveshaft are you using?

rs94z28

iTrader: (3)

behind front seats in center...sounds like the diagnosis above...IMHO...might do to check angle before throwing money at it!!!

BADSZ28

iTrader: (39)

4.11. Custom 3" steel unit with 3R up front and 1350 in back.

BADSZ28

iTrader: (39)

I don't see how you can throw off pinion angle on a fixed angle TA. I have a chassi mounted TA/trans mount too so I am not flexing the mount or anything. I could check it anhow. Just need a tool to do so.

DRGnFLYZ28

You said you had the gears installed and rebuild. Was there anything wrong with the differential? If your control arms are off a good amount it might throw your driveshaft balancing off. Might a rim be bent? Did you check the torque arm and tranny mount bushing? It might be worn, torn or separated. Just some ideas.

Jimmard

iTrader: (12)

Tailshaft bushing in the transmission

TORCHD 02 TA

iTrader: (39)

i think that the DS is out of balance and will need to be re-balanced or your rear is not straight. What i mean is you may need get an adjsutable TQ arm and get a pinion angel finder and adjsut the pinion agnle

DRGnFLYZ28

Any update?

BADSZ28

iTrader: (39)

I pulled the shaft out and watched the output shaft on the trans. Seams true by the eye. My output shaft bushing is new. Driveshaft is new and ballanced.

I swapped the rear wheels/tires to see if that makes a difference (bent or unballanced wheel) but have not had a chance to drive it yet.

I did have oil coming out of the pinion yoke where the nut holds it on. Very strange. Never seen that before. So I tried to tighten that best I could. Will have to see if that stops leaking now.

I have a Detroit locker. Seams to work fine but this is the first and only locker I have driven.

Only other thing I can think of is a bent axle. Not sure how that would have hapenned though. I ran the car with the wheels on and off and I could see the right rear rotor was turning out of round but not sure if that is the rotor or the axle hub. What is the tolerance of an axle hub or rotor out of round? Obviously if the axle hub is out of round it will be amplified by the rotor and then wheel.

TORCHD 02 TA

iTrader: (39)

see my post above

BADSZ28

iTrader: (39)

Oh, I forgot to mention that my control arms are indeed even in length.

Torchd, I will try and get an angle finder on it and see where it is at. I can udjust my front mount to change the angle, but I can only go steeper (less parallel with the car). Where should it be? 2.5* I think.

TORCHD 02 TA

iTrader: (39)

usually you want the it to be at -1* or -2*

BADSZ28

iTrader: (39)

The fixed TA is preset at -2* so I should be good.

BADSZ28

iTrader: (39)

OK. I ran the car on stands and did see a wable in the wheel/tire on the pass side. I removed the wheel, bolted down the rotor and ran it again. There is a wable in the rotor. So now I am not sure if it is the rotor or the axle. Does that mean I may have found it though? No idea if this could cause the fibration I am having. I have new rotors and will put them on and see what that looks like. If it continues, then I obviously have a bent axle.