werrring coming from ?? help identify

[laack]

94 ranger 2.3l mt rwd.
130xxx

ive been noticing a wrring noise coming from i think the back half of the truck while moving. It sounds something like a lower pitched muffled whistle. It starts somewhere around 15mph and is audible until 40ish. I assume it is there after 40, but drowned out by road noise and surrounding traffic.

I can hear it with all windows closed with no clue where to isolate it. drivers window open, faintly heard but i dont think its from under the hood. Rear sliding window open it is more audible but im still unable to positively identify that its from the rear.

Its not from the engine or belts, i have shut the engine off and coasted. the noise is still there unchanged. reved in neutral while moving and it is constant sound, not dependent solely on rpm.

Pitch does change as speed increases, its a constant wrrrrr, not a chirp. Tires have approximately 20k on them with no abnormal wear patterns.

no shifting problems, no clunk when shifting or accelerating, no grinding/clanging...

recent mx: (noise present prior to and after)
new tie rods inner & outer
alignment
trans drain & refil (fluid checked several time since)
rear diff drain/refil (fluid also checked since)

 

[straycat]

Jack up the rear end (safely with blocks or jack stands) and then put in in gear and give it some gas. Listen for anything coming from the rear end / shaft or the trans area. Best if you have a buddy with you so they can help listen for anything as well.

 

[adsm08]

Well, sounds like you have eliminated everything but the drive train.

Jack up the rear and run it in the air on jack stands. If you still hear the noise, it is rear end noise. If you don't, it's tires.

 

[GoodOld85BlueBalls]

I had that happen once. It was comming from the wind going past my radio antenna. I removed it and the sound went away. I found one of those spiral ones from a newer ford and it did not whistle.

 

[legoms013]

Its either a bearing somewhere. Or your tires. Try rotating them.

My last set of tires were loudest what they had about 28K on them, and then the noise went away from then on.

 

[Guest]

IIRC, that truck has a carrier bearing in the drive shaft. Has the drive shaft been checked lately?

 

[laack]

IIRC, that truck has a carrier bearing in the drive shaft. Has the drive shaft been checked lately?

Professionally no. What am i looking for?

 

[adsm08]

Well, at this point I'd go out and buy a mechanic's stethoscope. They are like $15. Jack up the back and run it while listening to things that move.

And it will only have the carrier if it's a super cab. A regular cab should have a 1-piece drive shaft.

 

[laack]

Well, at this point I'd go out and buy a mechanic's stethoscope. They are like $15. Jack up the back and run it while listening to things that move.

And it will only have the carrier if it's a super cab. A regular cab should have a 1-piece drive shaft.

I believe that it is the carrier bearing. as far as the noise is concerned it is either that or the u joint just a couple inches to the rear of the bearing.

I grabbed the shaft just at the joint and next to the bearing and there doesnt seem to be any play in the joint, however it does move a bit and i can see the rubber around the carrier bearing moving quit a bit in its support.

Next question is how to i continue to isolate, or have i already and replace the carrier bearing?

Is there a DIY for the carrier bearing floating around anywhere on the internet that you are aware of? I've been looking but unsuccessfully.

here is an example i found youtube that is almost an identical sound

http://www.youtube.com/watch?v=siH5rBI6DeE&feature=related


edit: another question yet...If i already have the drive shaft off, is it recommended that i replace the u joints, I am not feeling any play in them, however they appear to be original (no zerks). I don't necessarily want to do any additional work, but i will if its the recommended procedure...

 

[Frank The Tank]

Check the diff level in rear? make sure it's not full of water or empty. It could be the e brake sticking some.

there are some videos on youtube...... but i haven't found one on a ranger yet. the tech section should have a write up on it here though.

 

[laack]

Check the diff level in rear? make sure it's not full of water or empty. It could be the e brake sticking some.

there are some videos on youtube...... but i haven't found one on a ranger yet. the tech section should have a write up on it here though.

This is what i found in the tech:
http://www.therangerstation.com/tech_library/carrier_bearing.html

fluid is good and fresh, only 500 miles old. same sound before and after. I have been doing everything incrementally. wheels spin free.

I'm going to drop the drive shaft and remove the shaft bearing. I've never dropped the shaft before, my question is once i have it removed, how do i disassemble the shaft coupling to replace the carrier bearing???> does it just pull apart?

 

[laack]

IIRC, that truck has a carrier bearing in the drive shaft. Has the drive shaft been checked lately?

Thanks for the help, it was the carrier bearing. I would have wasted time and money on all the u joints and still come up empty handed. it took alot of work to get it out. 17 years of rust and corrosion made it a solid afternoon project.