HELP!!!! loud whine under load

[renegade1]

so yesterday i finally put a new rear end in the sport- no more open 3.23 gears. put in a D4 from a junkyard so now she has limited slip and 3.79! HUGE improvement. problem is at about third gear and above (manual tranny) it makes a whining noise?? the noise stops instantly when i put it in nuetral and starts right back up when put in gear. also at low speeds it has a somewhat jerky feel to it.

so from what ive read it looks like it could be Ujoints? some have said pinion bearing or axle bearings... but those still move under power or not...

ANY advice, ideas, etc are greatly appreciated!!! she drives ten times better now but the noise concerns me :-/

 

[SkyJumper]

pinion bearing or axle

pinion bearing I would think is the culprit, if it was a U-Joint, then you would of noticed it with the old rearend, but by reading your statement, this became noticeable after JY rear installed.

Did you check and fill or replace fluid in rear?

 

[renegade1]

yea before we put it under the truck we took it open, put new oil in it (with the friction modifier), and resealed it. the fill plug magnet didnt seem to have an abnormal amount of metal on it

i thought maybe in removing the driveshaft we had somehow messed up the U joint?

 

[renegade1]

and it also confuses me that it only makes noise under load youd think anything in the diff would keep making noise even when in nuetral because the car is still rolling

 

[SkyJumper]

and it also confuses me that it only makes noise under load youd think anything in the diff would keep making noise even when in nuetral because the car is still rolling

No it does not work that way on the pinion, the force is applied only under load. When you take it out of gear or push in the clutch, then it is only free spinning without any pressure or torque applied.

But if I read your OP correctly, this happened after install, not with the old rear. Sometimes a axle bearing will this also, but most times it is a pinion bearing. A U-Joint as long as they are tight and there was no sign of end caps worn, I would not go there.

 

[renegade1]

(im just trying to look at all possible problems before i break the bank for the bearings) thanx for the help! i also read somewhere that if the pinion nut is loose then the preload will change, thus moving the pinion with torque vs no torque - causing noise vs no noise. does that sound correct? should i get out the torque wrench and make sure the nut is tightened correctly?

once again thanks for the help!

 

[SkyJumper]

(im just trying to look at all possible problems before i break the bank for the bearings) thanx for the help! i also read somewhere that if the pinion nut is loose then the preload will change, thus moving the pinion with torque vs no torque - causing noise vs no noise. does that sound correct? should i get out the torque wrench and make sure the nut is tightened correctly?

once again thanks for the help!

you could recheck the torque on the pinion nut, but I doubt it is the problem. But you never know with a JY rear, good luck with it., And I highly doubt you would break the bank on new bearings, and you will need to get a new seal also once you do that, bearings are cheap.

 

[renegade1]

you could recheck the torque on the pinion nut, but I doubt it is the problem. But you never know with a JY rear, good luck with it., And I highly doubt you would break the bank on new bearings, and you will need to get a new seal also once you do that, bearings are cheap.
06-01-2011 12:08 PM

i have to work tonight, but tmrw ill put the driveshaft and check the pinion nut torque- and if that doesnt work ill order the bearings from Napa. if im correct - you have to reset up the diff after putting the pinion bearings/seal in right? looks like another all day project

once again thanx for the help! whenever i fix the noise ill post back what the problem was

 

[renegade1]

all u joints are fine. could jerk the DS around without any movement - bearings on order so tmrw morning i should HOPEFULLY be able to fix her. is nice tho... when it sounds like your being chased by angry blenders other cars get outa your way!

 

[renegade1]

Solution to problem

thanks for all the help - you were right. pinion bearing was completely shot!! total PIA to fix but well worth it. she drives like a dream to all who have the wimpy 3.23 open rear diff - SWAP!!!!!!!! especially with the 31's. makes a major difference in power

 

[SkyJumper]

Cool, glad you got it fixed.

 

[jpoprock]

Whoa, this sounds like what might be the problem with my 2002 Explorer. It sounds like it's the tranny (I have new hubs and bearings already). But I have a "roar" type of sound, similar to when my bearings were shot in the rear, but ONLY under load. if I'm holding a speed, it's there. If I put it in neutral, it goes away. I've got 180K on this truck, so there is a great chance that it's the pinion bearings. I wonder if this is a "do it yourself fix"? I did my own hubs, springs, shocks, etc. Or if it's too involved for me?

Also, is there only ONE pinion bearing? That just shows you how little I know. I research until I feel comfortable with a fix, then I go for it, or pay to have it done.

Thanks!
Jason

 

[merbs]

pinion bearing?

Sounds like a pinion bearing to me!It`s not so much about 3rd gear as THE SPEED YOU ARE GOING WHEN IN THIRD WHILE ACCELERATING!That`s when pinion bearing problem stand out.Usually around 50 or so while accelerating
and disappearing when you let off.Let whoever you bought it from know right away.The pinion nut seem tight?Check fluids?Say a prayer?Luck dude!

 

[merbs]

Jpoprock you know what the pinion is,it`s the gear that hooks to the driveshaft,there are 2 pinion bearings 1 in front and 1 in back of the gears.Changing them is simple,but if let go you should probably change both pinion and ring gear-make sure you get the same ratio as the front.Mustangs unlimited has a great selection as does randy`s ringandpinion.com his yukon line rocks.Changing the parts is simple but setting up clearances is the problem.Do it wrong and your right back where you were minus some scratch.Do you have and know how to use a dwell meter?If so go for it.With a torque wrench of course.

 

[jpoprock]

Well, I can set a pinion on an RC car all day long, but i'm not sure about my Explorer! I think the Tire & Auto shop across the street from where I work is going to take a look next week. They say they can do it no problem, and will likely replace my axle seals while they are at it. I'm sure I could DO IT, but I'm also sure that if I don't get it just right, it will destroy itself quickly.

There is no way for me to know just how tight is too tight, etc. Too loose, and it's gonna strip. I wasn't sure how many bearings there were, but you said two. Plus there are spacers/lock rings of some kind too I bet.

I'm just relieved to know it's not the tranny, and it's something that should be half way affordable. Though I'm not sure how much a REASONABLE shop would normally charge to do such a job.

Also, if they are going to have the A-arms off, I might as well hand them my Strutek strut/spring Quick Change kits to put on the rear right?? It might cost me a little bit of labor, but it should be VERY easy for them to do since they'll have it on a lift. If they aren't going to have that stuff unbolted, I'll wait and do it myself. I need the fronts done too. I was fully prepared to do it myself, but I'm just thinkin'.....