REAR END NOISE QUESTION
 

Hi, Think I need some guidance and help.

On my '66 GTO, I had the rear end gasket, and pinion seal replaced (area of question), as there was seepage showing from both.

New gasket, seal, fuid & posi additive done.

Driving home, noticed an apparent noise in the rear. Almost a growl, not a whine.

Did a bit of research on line and it appears that the new pion seal should be torqued @15-25 inch pounds, & a used seal at about 10-15 inch pounds. And if incorrect, could cause a growling type noise.

1) Has this been anyone's experience?
2)Should another new seal be installed?
3)Research states that minimal inch pound adjustment can eliminate or make it worse. Correct?

I ask, as I have had no real "rear end" experience, and need advice, before I got back to the repair shop that did the work.

Thanks for your help!!:)

Pinion seals are not torqued. The pinion nut affects the preload on the pinion bearings, the preload is different for "new" bearings vs. used bearings. Preload is tested with an inch-pound torque wrench. Spinning the pinion (with the differential case REMOVED so the pinion gear is not meshing with the ring gear) should require the torque specs you provided. The torque specs are not how tight the nut is tightened.

Once the nut is tightened, it cannot be adjusted "looser" without changing the crush-collar. Pinion bearing preload can be increased, but not decreased unless a new crush-collar is used.

The "typical" process for changing a pinion seal WITHOUT changing the pinion, pinion bearings, or the yoke (changing ONLY the seal) is to mark the pinion nut, remove it and the yoke, swap seals, install a repair sleeve on the yoke as needed, then put the nut back exactly where it was, plus a RCH additional.

The service manual states that you should mark the pinion nut relative to the pinion stem and after replacing the seal, tighten the nut so the mark on the nut goes past the stem mark by no more than 1/32"

George

The mark needs to be done with a scribed line, not a wide ass black marker or such.

I’d say the pinion nut is loose. That’s causing some gear mesh noise. If the pinion nut wasn’t scribed before starting, it may be appropriate to disassemble and at least replace pinion bearings, crush sleeve, and pinion nut. Then the rotating torque can be set exactly right. You have to sneak up on the correct torque. Too far, and the crush sleeve is ruined. Raytech makes a “Smart Sleeve” that’s much easier to crush.

don't go in reverse and hit the gas hard. Tighten that pinion nut with xx ft-Lbs TQ and see if the howlnHum are gone.

off topic, but i posted a thread about my ex girlfriend on reddit once with the exact same title as this thread.

What was the noise?

I bet it sounded like stirring macaroni

This is correct.

apparently chiphead and i have dated the same girl at some point!

Use red loctite on the threads if reusing the pinion nut.

I ain't even mad

It does bring us full circle to the crush sleeve being too large for the pinion stem, unless you give it an extra cinch.

she didn't say much about an extra cinch, sounded like she wanted more than an extra inch 🤣

THANKS, for the information!

On BOTH types of "rear end noise"!:clap2:

I guess one solution is "inch pounds"!:pound:

The other solution is just in "inches"!:noidea:

I was told if too loose, it creates a "whine" sound, and if too tight, it makes a "growl", "grind" type sound!

Any truth to that?

I'd just like to get it fixed correctly, so it's quiet like it was prior to the seal change, and Tremec "TKX" install!

Does the "Tremec" transmission have noise? Compared to a Muncie "M-20"?

Just trying to learn, and thanks for the patience and advice! :focus:

If it was fine before the pinion seal replacement then you just need to tighten the pinion nut enough to get it to the position is was at before the seal replacement. The correct way is to remove the axles and differential and tighten the pinion nut until you reach the proper preload of around 12-15 in-pounds. Without a scribe mark made prior to seal replacement you have two choices, the correct procedure or trial and error.

And by preload, you mean the force (in inch/lbs) it takes to rotate the nut/yoke/pinion/pinion bearing assembly without the ring gear and carrier installed, correct? This requires almost full disassembly of the differential to do this test.

Just want the OP to be clear in his understanding, as the torque on the nut itself may exceed 150 FOOT/LBS (not inch/lbs) to actually crush the sleeve the correct amount. So it appears that you set pinion bearing preload by crushing the sleeve as you torque the pinion nut. Then you verify the setting by testing how much force it takes to rotate the pinion, before you install the carrier.

https://www.stevesnovasite.com/threa...g-seal.124301/

[QUOTE=chiphead;6601433]And by preload, you mean the force (in inch/lbs) it takes to rotate the nut/yoke/pinion/pinion bearing assembly without the ring gear and carrier installed, correct? This requires almost full disassembly of the differential to do this test.

Yes, that's correct.

Thanks,
I need to verify if he scribed it, or trial and error.
From whatever his answer, I'll be happy, or pissed!!