4x4jeepmanthing

99, 4.56, np242/auto, hp30-open, 33s, 213,756
hey all,

the situation boils down as such,

Ive been trying to find a front end squeal for a month now. For a long while I thought it was brake related because its the only thing that wasnt as new as the rest of the moving parts.

Brakes: installed myselft, napa composite rotor, Hawk HSE pads, 3 years old all in good condition. I greased the slides and thought this solved the issue for a day, nope.

Gears: USA standard 4.56 and USA master install kit from RWK,- 22,300 miles on them, professional 4x4 shop installed .007 backlash, bearing preload 15ftlbs. ring gear 55lbs, bearing caps 60flbs, under 1.1 year old, Pinion seems like where the whine/squeal is coming from- 10 mph or under, .5-1mm side/side up/down play, 1mm in/out maybe, its still very solid feeling.The diff fluid was changed at the advised 500 mile mark and checked every 10,000 after. The noise is very high pitched, similar to brakes, and while braking it will change rpm almost to a skip/chirp, but I do not believe the brakes are this issue still- idk know how to 100% rule these out other than somehow removing and capping lines.

Hubs: installed myself, all torqued properly, 3 month old timken, very confident these are not making this noise

-just removed front DS because of vibes, slip joint wiggled at 70 mph, need new shaft likely

- ill be contacting the 4x4 shop tomorrow just to pick their brain.

ive only been able to replicate this noise once by jacking up a tire and spinning it today. Normally this sound is only at low speed, fairly consistent, but not 100% of the time, sometimes is takes turning a bit to put load onto something to squeak no matter right or left, nor does it squeal always while turning. It will not make this sound driving in reverse and it does still make the noise with the DS removed.

If a pinion bearing is the culprit, which one is likely bad (inner/outer) and how will a shop check? How can I check?
I worry about bringing it in and being told its bad even, if it isnt just so they could charge- ide like to think not, but its why other than this I never let shops "fix" my vehicle anymore.
I also worry that if I was to check everything myself, they would know its new diff oil and not stand behind their work blaming me for tampering, easily done. Dont get me wrong, these guys were very thorough on a complete inspection of the vehicle which is standard for them, they nailed many other unrelated issues upon inspection.

If it is the pinion, I believe the DS played a rolln in damaging it, not the shop, but I dont know enough to be sure. Youtube hasnt provided any replication of this noise for bearing related noises.
I feel like im up S__T creek on this one.

Lastly, if a pinion bearing is bad, how will this progress as its driven, its my only wheels DD?


Thank you immensely for your input!

~Matt

89eliminator

pull the driveshaft. take apart the axle shafts and just run the stub shafts in the unit bearings. if its diff related, you wont hear the noise anymore.

TRCM

if you do the above, make sure you seal off the axle housing tubes somehow to keep crap out of the diff & oil in it.

4x4jeepmanthing

Can it just have a rag on each end or do I need to plug the seals?

89eliminator

rag will be fine. or just dont take sharp turns.