Rear end ?????

[cutlassmann]

Question I had my rear end rebuilt 10 bolt with 3.42 gears in it and i had front and rear disc brakes put on at the same time with my new rims and tires I drove it and i'm getting a bad vibration in the front but i have had my front end rebuilt new everything and i had the tires rebalance twice and a friend of mines said it could be my rear end could that be true what do you think are could something be out of balance or did i get f@#$% !

[bryant]

differentials usually dont vibrate. ive only seen 3 things in a rear that will cause a vibration.
the pinion bearing go bad to the point where the pinion is not supported and allowing it to flop around. not likely sense its just rebuilt.
the pinion bearings not being proper preloaded and allowing the pinion to flop around. possible sense it was just rebuilt
the yoke being worn out where the u-joints seat in it. rarely see that happen to the point of vibration.
the first 2 will have oil leaking out of the seal.

chances are that if you changed gear ratio from a numerically lower gear like 2.73s, the higher rpm of the drive shaft at the same speeds as before is now showing a balance problem with the drive shaft.

what speeds are you feeling the vibration?
where is the vibration, the steering wheel, rear view mirror, seat, shifter, ect?

[cutlassmann]

my brake pedal shake and the front end is shaking it's starts around 60 then when I get up to 75-80 it smooth out.

[csouth]

I would check pinion angle and drive shaft balance. Is this the same drive shaft from your previous setup?

[bryant]

usually a drive shaft vibration is felt in the seat, shifter and seen in the rear view mirror. it will be an extremely high frequency. i dont know how to describe the difference between the really high frequency of the drive shaft vs the lower frequency of a wheel or tire caused vibration.

usually a front wheel or tire vibration will be mostly felt in the steering wheel.

are you feeling it in the brake pedal when your pressing the brakes or is it it vibrating in another way?

i would suggest trying another set of know good wheels and tires on the car. ive seen new tires have defects that cause vibrations and even cheap wheels that were unbalanceable.

[shep]

Sounds like a belt in the tire to me.

[cutlassmann]

Yes it is

[cutlassmann]

I have a new set of BF KWD Tires on it with bonspeed wheels.

[cutlassmann]

I was thinking the low profile was doing but a buddy of mine had the same set up and he said his was never vibrating

[cutlassmann]

Yes it has been cut and balance for my 4L60E tranmission

[cutlassmann]

Its 200% better it was the drive shaft thanks god.

[csouth]

Its 200% better it was the drive shaft thanks god.

I'm glad you finally found out the issue.

[cutlassmann]

THANK YOU GOOD PEOPLE OF THE AUTO WORLd!!!!!!!!

[cutlassmann]

the brake pedal and the car feel like the wheels are about to come off could it be the ball joints are the center link you think?

[bryant]

the brake pedal and the car feel like the wheels are about to come off could it be the ball joints are the center link you think?

thats a pretty vague description. i would suspect the brake rotors are warped or have to much lateral run out. this would cause a pulsing in the brake pedal. the front end is simple to inspect for loose components. jack the front end off the ground and safely support the car on the frame with jack stands. now you can shake a wheel at different clock points with you hands to check the different suspension joints.
with your hands at 12&6 o clock and push and pull with your hands with opposite force on each hand. most play felt at this location is bad ball joints.
now grip the tire at 3&9 and try again. this tests all the steering linkage.
lastly grip 1:30 and 7:30 then the 4:30 and 10:30 postilions. this checks wheel bearings.
if you get looseness at all positions, the one with the greatest amount is the biggest suspect is the culprit. then having some one look at the joints while you shake the tires should be able to see the motion in the worn out joints.