Pinion noise?

[JoeOmerta]

So over the weekend i replaced the transfercase input shaft seal and the rear pinion seal. I marked the pinion nut and my buddy counted the threads. When reassembling everything, my buddy thought i went past my mark by 1/8-1/4 turn but i thought i was still 3/4 turn short.

After going for a test drive now anywhere above 50mph, if i let off the throttle, or go back on the throttle, i get a quick grinding noise. But no noises any other time. Does this sound like the pinion is too loose or is this more of a too tight scenario?

Could i have reinstalled the transfercase wrong? it's only 6 bolts and i feel like that would leak or make a ton of noise all the time.

Click for SOLUTION

 

[M1Gunner]

Unfortunately, it's never a good idea to go off marking the nut and counting threads. Even if you use measure the how how far down the nut was tightened to. It's all about bearing preload and you have to use a beam type torque wrench. And different applications call for different specs for example a brand new/ overhauled rear end the torque spec will be slightly different than taking the flange off to replace the seal. Its all in inch lbs of torque too so it's a delicate process.

When ever you let off the accelerator the coast side of your ring gear is now in contact applying force to your pinion. When you get back on the accelerator the drive side is now back in contact. So that initial contact is applying the force which is causing your bearing to grind/growl. Typically that indicates a bearing with too much clearance.

And the transfer case can only go on one way really. You would know without a doubt if it was indexed wrong.

 

[JoeOmerta]

Can i use a beam torque wrench on the pinion with everything else in the axle or would i need to disassemble everything first?

 

[M1Gunner]

View media item 26331 Everything together and wheels on. You will have to of course drop the prop shaft.
You'll have to tighten the pinion nut in very small increments and then go back and use the beam type torque wrench to check the rotational torque for proper preload

 

[JoeOmerta]

Do you know off hand what the specs are i'm trying to achieve? It's the GM 10 bolt, 3.73 gears, G80, and i believe 8.5" ring gear

 

[#1taho]

Sounds like the pinion bearings are on the way out. I chased that problem for two years before I replaced them !!! Finally problem solved

 

[rockola1971]

Same prior problem on my 99 Sierra Z71 OBS. Had to do a complete teardown and replaced axle bearings too. The noise makers were the pinion bearing and the drivers side axle bearing. Both had marks in the race and the on the roller surfaces. Hell it had over 200K on the clock by then. Mine made noise for almost 2yrs before my lazy ass finally got in on a lift.

 

[01ssreda4]

The PINION (pinion only nothing else) preload is around 15 to 20 inch pounds with NEW bearings. I shoot for 20 on new bearings. With old bearings I'd probably go by feel or shoot for slight drag, say maybe 5 inch/pounds. How the heck you gonna get a reading with brakes, axles, and several OTHER sets of bearings rolling at the same time. Use common sense dude.

 

[01ssreda4]

View media item 26331 Everything together and wheels on. You will have to of course drop the prop shaft.
You'll have to tighten the pinion nut in very small increments and then go back and use the beam type torque wrench to check the rotational torque for proper preload

You need to stop giving advice dude, really. You dont have a Fing clue what you're talking about.

 

[M1Gunner]

@01ssreda4 When replacing the pinion seal, it does not require removing the wheels let alone the axles. Simply lifting the rear end. Maybe you you should do a bit more research.

To each, their own.