Diagnosing driveline sounds give me a headache

Good lord...sound proofing(but apparently not enough)+ not driving with your windows up for months= not noticing annoying sounds

So recently I drove my family to a family event..needless to say windows were up and music was down. Uh oh...i started hearing this noise that has been driving me nuts I cant un-notice it now

I recently had my gears changed to 4.56 motives, haven't heard anyone complain about gear whine with them so i though i would have no problem. Unfortunately the shop said if there is whine since motive isn't the gears they sell they wont warranty them against whine. I didn't notice any whine honestly but then again im not sure if ive ever heard a definitive gear whine. So im not saying it is gear whine...i hope it isn't.

I cant exactly pin point when this noise started but i noticed it last thursday.

Explanation of the sound. It is sort of a whirring whining+slight vibration. This sound only happens(or is only noticeable due to exhaust?) around 1300-2000 rpm...only when pressing on the gas pedal or on certain downshifts. Coasting there is nothing nor when i floor it. I can tap the gas pedal lightly and it will do it for a few seconds and stop.

I CAN'T FOR THE LIFE OF ME TELL IF IT IS COMING FROM THE FRONT OR THE BACK (sorry or the caps but i'm screaming inside)

short video...turn up your sound and you will hear it.

To me i thought the tire was rubbing on something...from what i see it isnt touching anything+ plus since it only happens when on the gas it could be that

Other ideas just spit balling here.
Serpentine belt
something with the tranny?
cv shaft?
driveline related....

I do have one bad seal on the driver side cv shaft but i doubt it is that..fixing that soon.

Kind of lost for answers lol

I was looking at this Identifying Bad Axle Noises - Four Wheeler Magazine but i cant identify with any of them.

Im going to try to jack it up tomorrow and play around to see if anything is loose. I'll also be doing some red neck testing and throw it into drive to see if i can find the location of the noise.

Ideas appreciated

I'm not a mechanic by any means but it seems to me that if it was the gears whining they'd be doing it the whole time. The gears don't stop spinning or turning if you take your foot off the gas. Strange noise for sure though. Have you made sure there's enough dope in the diffs?

JDW123 said:

I'm not a mechanic by any means but it seems to me that if it was the gears whining they'd be doing it the whole time. The gears don't stop spinning or turning if you take your foot off the gas. Strange noise for sure though. Have you made sure there's enough dope in the diffs?

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If by dope you mean oil, no I'm not sure.mgood question. I know my front seal is leaky but I don't think it is that leaky. I'll have to check that too.

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Sounds like it could be the pinion bearing? Did they use a crush sleeve or solid pinion spacer?

6.7CumminsDrvr said:

Sounds like it could be the pinion bearing? Did they use a crush sleeve or solid pinion spacer?

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I'm not sure, whatever came with the motive master install kit. If it's the pinion bearing when I jack it up the drive shaft should have some Play to it right?

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I cant watch the video at the moment, but I will try to remember tonight. Not to be the bad guy here, but the gears can change based on acceleration and decal. They don't stop turning, but the force being applied to them changes (I guess?). I don't know, but ive heard plenty that made slight noise cruising and lots of noise when coasting off the gas. That being said, my initial thought is that's not your problem.

As for your pinion bearing question, yes. It would be the yoke that has the play in it, but yes... and it would probably be leaking. If you can move it at all, no good. Its really easy to over crush the sleeve.

one last negative comment lol, Motives are notorious for whining. In fact after installing probably ~50 gear seats on trucks and jeeps, its probably the only one we have had to go back and redo. I think we had one failure with Yukon in a JK, out of 30+ or so. And its normally the Chrysler axles that have the worst problems lol. We did 4 sets of motives on a Dakota once, they ALL had problems. We ended up installing OEM gears back in that thing, what a disaster.

Did some exploring with the truck on jackstands...i couldnt isolate the sound by throwing it into drive too many noises from the outside.

Findings...i need some kore high angle cv shafts if i dont want them to snap at full droop lol but not the problem.

I attempted this http://www.ramforum.com/f53/front_end_howling_noise-26976/ wasn't that.

Drive shafts.....front no play at all

rear....uhhh is it supposed to have that play..? I know driveshafts have a little rotational play but is it suppose to clank like that? (coming from the diff) It also clanks a little is a jiggle the wheels back and forth. I have a yukon duragrip lsd

rear drive shaft pinion angle? could that be a problem?

Are our driveshafts foam filled? I know that wouldn't fix whatever it is but it would deaden it maybe enough to not bother me...if it is even coming from the rear drive shaft.

okay...so i have it on good authority from someone i let drive my truck...who doesnt like to blast the radio and drive with windows down that it was making that sound prior to the gear swap.

So for a moment lets forget about the gears making the noise. They very well might not be making it.

What could it be?

Slipping belt?
rear driveshaft pinion angle?
rear driveshaft un balanced?
tranny?

give me some ideas guys!

guess no one has anything for me!?!? oh wellll should be fun

So I finally heard the video. Wish I could help but it's hard to diagnose without riding in the truck. To me, it sounds gear related. The fact you can manipulate when the sound occurs by applying throttle leads me to beleive you have "slop" somewhere in the drivetrain. Your backlash could be off but you would probably hear more gear whine. It really sounds like there is a bit of play in the pinion but who knows?! It is possible you are getting some noise from rear output on the tranny.

6.7CumminsDrvr said:

So I finally heard the video. Wish I could help but it's hard to diagnose without riding in the truck. To me, it sounds gear related. The fact you can manipulate when the sound occurs by applying throttle leads me to beleive you have "slop" somewhere in the drivetrain. Your backlash could be off but you would probably hear more gear whine. It really sounds like there is a bit of play in the pinion but who knows?! It is possible you are getting some noise from rear output on the tranny.

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did you see this second video?

no play back and forth or in and out but it did this in neutral. I hope if its gear related there is still time to fix it and the gears aren't ruined.

So i digress..my reliable source that said the noise wasnt there prior to the gears...well they must have been wrong. Took the gopro out today and put it as close to the diff as i could. Sound like a blender to me..........little too extreme for just "gear noise" corrrect? They said they wont warranty gear noise but this seems a little extreme since it vibrates too. Also in the first part i am shifting from drive to reverse a few time, the drive shaft seems to move a good amount prior to the wheels even moving. IS this a pinion issue?

video: https://www.youtube.com/watch?v=6aAMKjg1bZQ

I still can't offer anything worth while but after you started going down the road I said to myself: "I thought that was a v8". Sounds like a motorcycle was riding beside you the whole time. Definitely not normal.

lol tell me about it!

I'm pretty sure it is a pinion bearing. the one that is inside the axle. Rather it is not a good quality, rather it was over-tighten while being installed

Pmexpert said:

I'm pretty sure it is a pinion bearing. the one that is inside the axle. Rather it is not a good quality, rather it was over-tighten while being installed

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hmm okay, i bought timken bearing for them so im guessing it is the over tightened or too loose factor then

kg93 said:

hmm okay, i bought timken bearing for them so im guessing it is the over tightened or too loose factor then

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You got to disassemble it. If them where over tighten, you will see the wearing on internal side of a bearing face.


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Pmexpert said:

You got to disassemble it. If them where over tighten, you will see the wearing on internal side of a bearing face.


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thanks for at least giving me an idea of what to tell them when i take it to the shop. Ill let you know if you were right. I hope driving it like that for 500-1000 miles didnt destroy the gears.

kg93 said:

thanks for at least giving me an idea of what to tell them when i take it to the shop. Ill let you know if you were right. I hope driving it like that for 500-1000 miles didnt destroy the gears.

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If it is bearing I meant, gears are not damaged hopefully, but you will see a dark marks on inner side of the bearing face, were the rollers were running. So in that case bearing is damaged unfortunately so need to be replaced. This could make also some extra backlash on gears as pinion has moved a bit out. Which gears brand is used in your application?