Rear Axle thumping

[Wayne67vert]

The rear axle on my 99 Tahoe limited is thumping so much I feel it in the floor. I thought I had a tire with a flat spot.
It seems there is a gear going bad.
How difficult is it to replace the gears in the axle?

 

[MO Viet Vet]

The first thing to do is not assume the worst. It may be a u-joint going bad. If you drive much further you may do further damage. Get it looked at by a qualified tech or shop and report back your findings.

 

[Ice98]

I had a vibration felt through the chassis and it turned out to be my spindle bearing going bad, I was shown a picture of the magnet in the transfer case and it was about 3x the size of normal with metal shavings, ended up having to have a new rear end put in at a cost of around $1,100 with labor...sucked

 

[Wayne67vert]

I have an appointment in the morning to check it out.

 

[MO Viet Vet]

Let us know. Good luck.

 

[lesterl]

I would jack the rear end up and turn wheels/ drive shaft by hand..... see if you can "feel" where the thumping is at....

 

[Wayne67vert]

I would jack the rear end up and turn wheels/ drive shaft by hand..... see if you can "feel" where the thumping is at....

I did that, I think it's in the gears. I feel it and hear it on every revolution of the wheel. To me this eliminates the u-joint.

 

[lesterl]

Yup, sounds like you broke a tooth on the Ring Gear......

 

[MO Viet Vet]

I might have even agreed had I known that in the beginning.

 

[Wayne67vert]

My mechanic checked it today. Listened to rear axle with a stethoscope and says the left outer bearing is a little noisy, not enough to make the thump.

He pulled the driveshaft, found the front u joint bad. I had him replace both u joints. Problem not corrected.

He feels the right front hub has some issues and should be replaced. It could be making the thumping I feel in the floorboard. He also noted the brake rotors are very deeply scored and recommends I replace them with new pads.

I am going to handle the brake and the hub replacement myself.

I'll let you know what I find,

 

[lesterl]

Good luck, let us know what you find.....

If you had the rear jacked up, and truck was in park, the axles, drums, bearings and spider gears are what are rotating.......

 

[Wayne67vert]

Ended up being the right front wheel bearing was going bad. I replaced the right side first and then drove it. The thumping was gone, YEA!
I changed the hub/rotor on both sides along with new bearings on both sides and new ceramic brake pads.
It rides like new

 

[MO Viet Vet]

LOL! Now you need to get better at telling where the noise is coming from. That is funny! Glad it is fixed. Can now lean back and sit a little deeper in the driver's seat!

 

[Wayne67vert]

Well it's a new vehicle to me.
It came with bad tires, a bad pitman arm, a bad u-joint, a driver side caliper hanging up, a fuel gauge and temp gauge that didn't work, sunvisors with the mirrors ripped out, and french fries and toys under the back seat.
It also has only 104,000 miles and I gave $3700 for a special edition 1999 Tahoe Limited that they made 8700 of. I has the police package suspension with over size wheels and tires. This has unique body side moldings and black out bumpers and grill trim. All the windows are tinted from the factory.
It came with additional oil and transmission coolers and larger brakes.

I like this truck and feel it's worth bringing it back to decent operating condition.

 

[MO Viet Vet]

I agree completely. Good luck.

 

[lesterl]

Whats the brake system RPO code? JB5?

Yeah, big difference in front and back noises... Glad it is fixed...

 

[Wayne67vert]

Funny thing was, I could feel it in the floor, not the steering wheel.

 

[Wayne67vert]

Whats the brake system RPO code? JB5?

I'm not sure, the list I have calls for
Power brakes
4 wheel abs
front discs 11.57 x 1.25 in
rear drums 10 x 2.25

 

[lesterl]

RPO code list in the glove box should be a 3X5" decal with 3digit codes all over it....

 

[Wayne67vert]

RPO code list in the glove box should be a 3X5" decal with 3digit codes all over it....

Yes JB5 is the brake code. What does this tell me?