Pinion Gear - 98 5.7L Vortec Suburban

[shultzee13]

Hey Guys on 98 Chevy Suburban LS 2wd my mechanic says the pinion gear is out after driving it, but wouldn't I have some up n down or side to side movement? With the vehicle jacked up I have no movement. I can slightly turn the driveshaft but not much.

Before I spend $800 redoing the pinion gear I just want proof that is what is making the noise which is a dull roar at 35 mph up to about 65 or so.

Transmission shifting fine. No codes.

Mechanic drove it only. Did not jack it up and inspect. The roar quits if I take foot off the accelerator or shift into neutral.

Could it be the Ujoints?

[95 S_Trucker]

It could be the pinion gear. Without driving it or hearing the noise, it sounds more like the pinion bearing. Bearings can make noise and not have any play.

If you are driving at 50 mph with your foot off the gas, and shift into 3rd, does it make a similar noise as if you are accelerating?

[shultzee13]

I take my foot off the accelerator at 50 mph and the sound is gone.

[95 S_Trucker]

When you downshifted to 3rd it was gone?

[shultzee13]

My suburban is an automatic. It's gone at about 60 miles per hour and on up. Only hear it at 35 to 55 mph.

[95 S_Trucker]

I know. Pull the shifter down into third.

[shultzee13]

O sorry. Was just clarifying. Yes sir, still there. Even in 3rd.

[95 S_Trucker]

I doubt its the pinion gear itself then. The pinion wears on the front side of the gear, it doesn't wear on the back side. The ring gear would wear with the carrier. If the pinion gear is worn, that also means the ring gear is worn and needs replaced too. I would vote for the pinion bearing, because the noise is present when decelerating. The outer bearing(which fails more often) can be replaced fairly easily by removing the yolk and the pinion seal. And putting the preload exactly where it was. The carrier would have to be removed to replace the inner pinion bearing.

[Jeepwm69]

Originally Posted by 95 S_Trucker

The outer bearing(which fails more often) can be replaced fairly easily by removing the yolk and the pinion seal. And putting the preload exactly where it was. The carrier would have to be removed to replace the inner pinion bearing.

Guessing this would be done just as you were replacing the pinion seal if you didn't want to replace the crush sleeve?

[shultzee13]

Originally Posted by 95 S_Trucker

I doubt its the pinion gear itself then. The pinion wears on the front side of the gear, it doesn't wear on the back side. The ring gear would wear with the carrier. If the pinion gear is worn, that also means the ring gear is worn and needs replaced too. I would vote for the pinion bearing, because the noise is present when decelerating. The outer bearing(which fails more often) can be replaced fairly easily by removing the yolk and the pinion seal. And putting the preload exactly where it was. The carrier would have to be removed to replace the inner pinion bearing.

Is there a way to replace the outer pinion bearing without removing the rear end gears? The only thing I see when I remove the pinion seal is the shaft and a black seal around it. I see some metal behind this black seal but….

[shultzee13]

Originally Posted by 95 S_Trucker

The outer bearing(which fails more often) can be replaced fairly easily by removing the yolk and the pinion seal. And putting the preload exactly where it was. The carrier would have to be removed to replace the inner pinion bearing.

How? Ive removed the yoke and the seal.

[nixrox]

You cannot replace the front pinion bearing by just removing the yoke and seal.

How are you supposed the remove the inner race, because that is probably what is making the noise? You need to get a puller in behind that race to pull it out. It has never just fallen out whenever I replaced those bearings.

[nixrox]

I would also check the U-joints for excess wear. If you have more than 100,000 miles you should probably change them anyway.