Pinion Bearing Noise (I think)

[3MAX]

I went through the exact same thinking you are going through right now. And I had the exact same noises you are having in the exact same situations, to where I couldn't think that it was the driveshaft/slip yoke being pulled out to far. But when I changed my setup....like I said....smooooth. The last thing I like doing is throwing money at parts that are not necessary

I certainly can't argue with that.

I'm going to go ahead and try the output shaft bearing since it's relatively cheap and easy, and since the T-case is the ONLY item on this Blazer that hasn't been rebuilt. If that doesn't solve it, I'll go for a CV shaft next.

I do appreciate your advice

 

[3MAX]

I went through the exact same thinking you are going through right now. And I had the exact same noises you are having in the exact same situations, to where I couldn't think that it was the driveshaft/slip yoke being pulled out to far. But when I changed my setup....like I said....smooooth. The last thing I like doing is throwing money at parts that are not necessary

Well, it looks like you're going to be right - I hope so anyway. I installed a new output shaft bearing and it resulted in no change whatsoever. I'm gonna live with it as is until I'm ready to drop the case and pony up for a SYE kit.

 

[blazinzuk]

Just for kicks check your torque converter to flexplate bolts. That was my noise and I swore it was the rear axle

 

[drivelineman]

Its gear rattle from angles . What is the pinion angle ? Jess

 

[3MAX]

Its gear rattle from angles . What is the pinion angle ? Jess

U-joint angle at the pinion is around 28*

 

[Kay86K5]

Well, it looks like you're going to be right - I hope so anyway. I installed a new output shaft bearing and it resulted in no change whatsoever. I'm gonna live with it as is until I'm ready to drop the case and pony up for a SYE kit.

Depending on how you are going to use the rig, you may not even need an SYE. The real reason why I did it to mine is because it's a trail rig. So I wanted the fixed rear output so if I broke a rear shaft, I could just pull it off and drive out on the front shaft only. If this is just a rig you like to drive around on the road and mild trail/camping stuff, you probably don't need an SYE. I guess it depends on what you want out of your truck.

So if you don't go SYE, you can just get a new CV shaft made with a slip yoke. This would save you some coin in the long run

 

[3MAX]

Update:

My driveline noise has continued to get worse. It's loudest during deceleration, but it's occurring during cruise speeds now as well. It only goes away during acceleration, up hill, or low speeds. It was to the point I did't want to drive it for fear of causing more damage.

So I pulled the differential apart to check things out. Gear pattern looked great. Pinion bearing preload is 7 inch lbs. New installation spec is 15-22, used spec is 7-9, so its within used spec (3500 miles on it). I do feel just the slightest bit of roughness when rotating the pinion.

Thoughts?

At this point I'm going to go ahead and put a new set of pinion bearings in it even though I'm not convinced this is the problem...

 

[dyeager535]

If you put the thing up in the air and put it in gear, can you isolate the noise that way?

I was just doing this Sunday, checking rear brake adjustment. As well as watching the rear wheels turn with the t-case in neutral.

 

[3MAX]

If you put the thing up in the air and put it in gear, can you isolate the noise that way?

I was just doing this Sunday, checking rear brake adjustment. As well as watching the rear wheels turn with the t-case in neutral.

Nope- I thought about this, but wasn't brave enough to try it. Would probably have to get it up to 30mph or so to make the noise on decelleration, and would need to be under it to pinpoint the noise. No Thanks!

 

[Stomis]

Nope- I thought about this, but wasn't brave enough to try it. Would probably have to get it up to 30mph or so to make the noise on decelleration, and would need to be under it to pinpoint the noise. No Thanks!

O dont be a wuss! Get your wife/GF out there in the drivers seat and crawl under that bitch!

Its really the best way to isolate a noise.

 

[3MAX]

Too late for that now anyway. Finished tearing it down tonight and inspected the bearings. Everything looks fine. I'll put it back together with a new set, but really don't expect it to change anything - we'll see.

 

[3MAX]

After gettng the rear end back together and taking it for a drive, the noise is still there (as expected). A lot of you have given me good advice on checking out other possible issues, I was just to stubborn to listen. I had convinced myself that it had to be the pinion bearings due to the sound and the conditions when it made noise, plus the fact that it's gradually getting worse... Oh well, live and learn. Time to look into a CV driveshaft I suppose.

 

[dyeager535]

Well hopefully you don't shatter the case before you replace the CV shaft.

Numerous instances of folks with 4" lift and shattered t-cases. Some get away with it "forever", others such as my friend lose the t-case/driveshaft at 60MPH.

 

[72blazerguy]

After gettng the rear end back together and taking it for a drive, the noise is still there (as expected). A lot of you have given me good advice on checking out other possible issues, I was just to stubborn to listen. I had convinced myself that it had to be the pinion bearings due to the sound and the conditions when it made noise, plus the fact that it's gradually getting worse... Oh well, live and learn. Time to look into a CV driveshaft I suppose.

I had a similar noise at the switch from accelerate to decelerate (no noise when accelerating). I didn't have the noise with 3.07 gears, but did have it when I regeared to 4.56. You would swear that the rear end was going to lock up or blow up. I went through the rear end a couple of times thinking I screwed up the rear end, couldn't find it. CV driveshaft fixed it when I put a doubler in.

The noise NEVER got worse .