Noise in driveline, pinion bearing?

[dkad260]

Now that I am more focused on the "growl" over the exhaust note, I'm almost certain that's what it is. Been busy last couple days so haven't been under it, hopefully by Saturday evening I will have this narrowed down.


Local shops around my area that specialize in drivelines are all around $1500 to rebuild the rear. I'm mechanically inclined enough to do this, I just haven't done one, can't be much harder than rebuilding an engine right?

I will pull the rear cover this weekend and take a look, will likely get a new set of OE ring and pinion gears and a master rebuild kit with setup bearings...the whole works. I have a vacation coming up and this would be a good stay-cation experience.

Will probably pull the axle for this as that's a piece of cake to do, and would make the job much easier.

Don't want to put the cart on front of the horse yet, but this is looking where it's going.

 

[j91z28d1]

just my experience, but unless you feel some slop in the pinion flange, and even then the gear whine starts before bearings, unless they are really bad like bad enough to see metal on the magnet, and not just the paste metal, gritty stuff.

I wouldn't be surprised if it's something else, I've had outer axle bearings roar thou.

I mean they would have had to straight impact the pinion nut down enough you could bearly turn it by hand for it to kill bearings sitting on oil. just what I've seen over the years. hopefully you find it. my first guess till I heard it was drive shaft, they can resonate like that but yours is more of a roar where a drive shaft is more of a hum.

 

[j91z28d1]

oh the tq spec for the pinion bearing drag is always listed without the ring gear in the axle. with the correct tools you measure it all up to get pinion depth shims thickness without needing the carrier in it. then you tighten the pinion nut till you get the drag torque spec and then install the carrier and shim side to side for back lash.

without the right tools. you either get lucky or assembly and disassemble 10 times lol.

 

[OR VietVet]

Find a trusted tech/shop and drain all the fluid and cover off and measure the gear lash and check the wear pattern. I was a little worried about mine and a "noise" and me and my friend stayed late one night at his shop and checked all that and the lash was in the middle of the desired readings and pattern looked good. New fluid and I went on a 15 day 5500 mile trip with no problems.

 

[dkad260]

I took it to a very reputable shop this morning, they put it on a lift and we looked at the rear axle, transfer case, front diff, all the axle bearings....they said it sounded good. The RR axle bearing had a hint of noise but nothing alarming...I plan to change those soon anyway.

Going back a month, I replaced my rear u joints and bent one of the ears slightly, so I took it to a shop and had both my driveshafts balanced and new U joints installed....all was good. I was surprised both shafts needed about 2 ounces of weight but it ran smooth.

When it was on the lift today, I could see both the driveshafts have noticeable runout....and it looks like alot.

The shop that balanced the shafts assured me the shafts were straight and balanced, but I could easily register .060" runout on the rear shaft with a dial gauge and it's likely a little more. The front has more runout but was too hot to get anything setup to measure around the converter.

I wiggled the yokes, used a prybar, and both front and rear driveshaft yokes are good and tight, no movement up or down.

I didn't think it was the driveshafts because I had a slight noise before as the rear u joint had slight movement, and it morphed into this, coupled with the rear pinion history.

How much "wobble" is normal? Should I be able to see it from 10' away lol?

 

[dkad260]

I've seen a number of drive shafts spin when they're in the air but I don't remember them ever looking like this...maybe I'm wrong.

Something must have popped loose inside when they welded the weights, that's the noise you can hear Inside the shaft. Wouldn't surprise me the welder was too hot and there's a piece of slag inside.

 

[donjetman]

yeah that can't be right

 

[j91z28d1]

I hate to say it, but I think I'd buy 2 new shafts of the best quality you can find since oem seems to be discontinued.

I'm no expert, but I would think that spinning at 80mph would be ******* everything, especially the tranny tail housing bushing. the pinion has a bearing but the tranny is just a bushing that's splash oiled I believe.

I don't know if it's the same as the old manual trannys, but I killed a few of those with vibration, took them down to the copper under the sliver/Grey coating. not sure if you can see it with the shaft out or not to inspect it.

 

[j91z28d1]

it sure seems to me that oem gm driveshafts are not meant to be serviceable. I think you have to melt that epoxy out to get the old ones out without damage and then the amount of heat needed is ******* the shaft.

 

[OR VietVet]

it sure seems to me that oem gm driveshafts are not meant to be serviceable. I think you have to melt that epoxy out to get the old ones out without damage and then the amount of heat needed is ******* the shaft.

I beg to differ. I have changed many pairs of u-joints and heated the keeper/epoxy to melt it out. The heat is not that much really. You are not heating it like you are getting ready to cut metal.