grinding noise......
 

Hey guys, trying to diagnose a recent issue with my 93 4x4 v6. I left the gym and all of a sudden i heard this grinding noise. like a bad bearing in a FWD car that you have been driving on for awhiile ha. Its intermittent but i hear it mostly when im pulling up to a stop sign and just before i hit the brakes i hear the sound and it sounds like something is grinding faster then my wheels are turning. It seems like its from the rear pass side. I did the 12 and 6 bearing check on the front and rear driver side. Both are tight. (repacked bearings on front 15K ago). No play in driveline except the center carrier bearing i cant tell. the boot is fine, i can move it around alittle but im not sure how to diagnose a bad center carrier bearing... Lastly i jacked up the rear end on stands put it in gear and got up to 80km/hr without making the noise...vibrated some...its always vibrated from 80-100km/hr since i got it... the tranny mount needs to be replaced. has some play.but i feel it is unrelated to my grinding noise. while the truck was on stands i rotated the rear tires and rear driveshaft with no binding being felt. the rear diff flange has a small lip and it doesnt look 100% straight when you rotate it but it doesnt have any play either..... truck has 315K had it since 300K and havent changed rear diff fluid.... might check that tomorrow night....i know this is a novel but i wanted to express all my observations......cheers!:drink:

The 3 squirrels that run in the hamster wheel are hollaring at you

Hahaha nice analogy. Dam I thought so.

I've never rebuilt a diff.......worth trying? Done lotsa work but not that .Or just slap a used one in?
I don't got 1k to pay someone.

Okay so i changed the diff fluid. no water which was nice to see, but pretty thick oil...and my breather was clogged, lucky i didnt blow a seal. Installed my extended breathers. The initial drive after fluid change i heard the noise but driving to work this morning i heard nothing. I got my hands on a 30mm for the pinion nut, going to check my bearing preload tonight.....only got 1.25 hrs of daylight after work up here in the frozen prairies.

Looking at how the 3rd member comes out of these trucks, i could rebuild the diff in the heated comfort of my works shop..... is re gearing necessary? i feel confident i could redo the bearings and just reuse my gears...but if im going to all that trouble maybe new gears would be a better idea.... i am running 31" tires on stock suspension but i'm having so much fun wheeling i really wanna get her lifted and get some 33's.... any suggeestions if i do need to rebuild my 3rd member?

Junkyard third member is gonna be a lot cheaper IMO. It didnt say anywhere but I'm gonna assume that you don't have a welded third member.....

Cheaper still is a whole rear end or atleast round here they are

There is very little movement in my pinion flange but the more i drive it the more it seems like its coming from the rear pass side tire. I cannot make the noise with the rear end jacked up...... and now that i think about it i cant just do a 6 and 12 check on my rear bearings, i would have the remove the entire assembly to check correct?
Found a used 3rd member for 150$cnd.... mine is not welded....would would be cheaper then a rear bearing ha because i certainly do not have a press or jig.

Bearing noise video
 

video:
:saw:

Sounds like a bad rear wheel bearing to me.

Scott

Grinding
 

Wheel bearing x2

That's what I figured. Not so bad after all.
Thnx guys :)

UPDATE: Got the rear pass bearing replaced. The original had some play with abit of noise.
I he-man'd it apart and the guys at work used a section of pipe and pressed the new bearing in with a fancy electric press.
So all was good for the first 5 mins of the test drive. then the noise came back but not nearly as strong but it seemed to be from the same area. Sitting in the drivers seat i immediately look at the pass door. it seems like the noise is coming from right behind me and to the pass side.
Before i replaced the rear bearing it would grind in 2wd and 4x4 and was random.
NOW it (so far) only makes that noise in 4x4.... My rear diff breather was plugged. i replaced it. Im now thinking its a transfercase issue (please god no) or a spindle bearing.....but it just doesnt sound like its coming from the front.... any clues, hints,or ideas guys? i am going to change transfer case fluid and front diff fluid this weekend:dunno:

UPDATE: Got the rear pass bearing replaced. The original had some play with abit of noise.
I he-man'd it apart and the Gguys at work used a section of pipe and pressed the new bearing in with a fancy electric press.
So all was good for the first 5 mins of the test drive. then the noise came back but not nearly as strong but it seemed to be from the same area. Sitting in the dirvers seat i immediately look at the pass door. it seems like the noise is coming from right behind me and to the pass side.
Before i replaced the rear bearing it would grind in 2wd and 4x4 and was random.
NOW it (so far) only makes that noise in 4x4.... My rear diff breather was plugged. i replaced it. Im now thinking its a transfercase issue (please god no) or a spindle bearing.....but it just doesnt sound like its coming from the front.... or a front diff issue.... any clues, hints,or ideas guys? i am going to change transfer case fluid and front diff fluid this weekend:dunno:

Tcase front axle side if it sounds like its behind you. If it sounds like its ahead of you when your driving its probably the front end

Axle bearings kind of rumble in my experience. Never had it come and go though.

A seizing U-joint can be hard to detect at first because most people just grab the drive shaft and see if its sloppy.

Have you looked at your brake shoes or hardware to see if anything is rubbing inside the drum?

Drive shaft yoke flanges sometimes work loose or get bent and rub.

I have had weird hard to find noises that ended up being exhaust related. Internal muffler cracks and converters that the media had broken loose from the shell.

Sorry, I couldn't really hear the video well so just throwing ideas out there.

I have gear drive cases. Is yours a chain type? Chain noise?

Maybe the guys with the V6 cases can chime in about this possibility.

Thanks for the reply guys,
Aztoyman, my muffler is a new flowmaster, rear shoes were done 15K ago and everything is nice and tight for the drum hardware. The pass rear drum didnt look like it had any unusual wear.
My T-case is 23 spline chain drive unit. I think. I checked the fluid level and tried to top up but its full. I greased my front driveshaft and checked both the front diff and front t-case yokes. both have no play. Quite tight actually. I was going to change fluid today in t-case but the shop only had 3 bottles of gear oil. The haynes manual calls for 3.4L so i will have to wait another few days.

Stetson, that does sound like its the front driveshaft side on my t-case. but the sound is random, and i cannot reproduce the sound while its up on jackstands and in gear turning the wheels.
Am i correct thinking that removing the front driveshaft proves nothing as its not spinning in 2wd?
I did notice while under there that my pass side front diff mount is loose and i can move it up and down about 1/8 of an inch.... not sure if that means anything.

Is there anything else that you guys can think of i can check myself before bringing the truck into a drivetrain shop? if the transfer case is growling at me and it is the chain......is there alot of concern or should i just take it easy on her until spring?

Again, Thank guys :-)

You know, it's that time of year again, cold weather coming on(depending on where you're at), and a common issue is the front spindle bushings lacking grease where the cv axles go through the hub. Search for "ifs spindle lubricator" or something to that effect. Cold weather seems to exacerbate the issue and it makes an intermittent grinding noise.

At least check it out, it could be almost free to just pull the cv axle back from the spindle and put a few pumps of grease in there and reassemble.

I don't quite understand your question but if you have the front drive shaft out and it still only makes the noise in 4x4 its definitely the tcase but if taking out the drive shaft makes it go away it doesn't mean its not the tcase because it may need to be under a load to make the noise.

Generally speaking no the front driveshaft doesn't spin in 2wd although on live axle 4x4s it dose if that helps

In my exprience Sealed bearings and greased bearings that are dry will screech and make noise randomly when they first begin to lock up but oiled and well greased bearings won't make audible noise till their fully locked up and by then the noise will be constant. I know that from workin on atvs so it might help you narrow down which bearing it is, if its a bearing