Rear End Wine Investigation

[awhughes]

I am currently at 131,000 miles on my Explorer. Recently I noticed a rear end ringing or a wining noise occuring at 25 mph and up. It does get somewhat louder at the higher speeds. Going around corners has not effect on the noise and it only does it whith the throttle versus in neutral at same speeds yield no noise. I have not yet changed the differential oil until today. I checked the level before changing it and it was just below the fill hole.

Today I removed the cover and drained the oil. It was still amber in color and did not smell burned, only the typical raunchy scent typical of used gear oil. The oil looked good. All the gears looked good with no real shiny color (spalling) or broken teeth. There was no metal chips or even fines in the fluid left in the little valley at the bottom of the housing. This made me feel some relief based on these observations.

I have not yet test driven it as I waiting for the RTV to set. I refilled it with 4oz. of friction modifier and 2.75 quarts of 75W140 fully synthetic gear oil.

Question 1: Has anyone experienced a faint wine all the sudden in the area of the differential and replaced the fluid and have the noise go away? I am hoping this will be the case for me but am skeptical as noises typically dont just go away without changing hard parts.

Question 2; Has anyone solved any wines described above by replacing the U-Joints? This may be my next thought.

Please respond with information on similar experiences and or solutions of faint gear wine.

 

[96limitedX]

my moms 94 had the EXACT same problem! we changed the rear diffy fluid-t-case-front diffy and still the same. only when on the gas. turns out her front brakes where toatly shot. the roators where so badly warn that it caused the pads to wear into the grooves and caused the noise. now i still have not figured out why it only happed when you where on the gas. but that fixed it. so its worth a shot to look at your brakes.

 

[spindlecone]

All kidding aside if it whines on decellaration, the diff is prob. toast.
That would be a killer name for a new Calif Wine (Rear end wine) would be a major seller in San Fran

 

[awhughes]

The wine does not occur on decelleration and my brakes are good. The wine is still there as I just test drove it. My next option is to have it looked at and analyze the noise from underneth with the truck raised in the air. I am still open to other suggestions though.

 

[spindlecone]

The wine does not occur on decelleration and my brakes are good. The wine is still there as I just test drove it. My next option is to have it looked at and analyze the noise from underneth with the truck raised in the air. I am still open to other suggestions though.

Tires? Proper inflation, do you rotate them, would look at them as the whiners

 

[awhughes]

The tires are properly inflated and recently rotated and have about 10K on them. I eliminated tire noise by putting the truck in neutral at say 45mph and the noise dissappears immediately. The noise only happens with my foot on the gas either coming up to speed or on cruise control at speeds above 25mph. It occurs in a load/torque situation only while pressing the gas.

 

[95Xsport]

I'm sure its the differential, in fact, my Explorer is in the shop now for 3 days to replace the differential because of whining when the diff is under load. My mechanic is outstanding and he knew right it away it was the diff. Everything you've said so far about your whine problem is the same as me: Wont do it in neutral, only happens under load, appears after about 20-25, gets louder, higher pitched etc. Mine was damaged due to being too low on fluid for too long and I SHOULD have brought it in sooner, now I'm paying $700 but it also had 197k miles on it.
I just took a video of me driving my X a few days ago before I would get it fixed so that I could give reference to others what a diff whine sounds like but I dont have it hosted online yet. My whine is horrendous and most people that have a whine dont have it as bad as I do since I waited much too long.
Did you notice any play where the shaft meets the diff? Mine was so bad it had 1/2" of play, its supposed to have NO play Also, if it goes to long, the diff could ruin the entire axle so I'd get that checked out asap.

 

[papo1075]

i just just had my ring and pinion changed and it started doing the same exact same thing im still trying to find out what it is. and im thinking bearings but it it was not doing it before they changed my ring and pinion.

 

[awhughes]

Update

Well the wine in my case came from a combination of multiple bearing failure. The following was replaced; carrier bearings, front and rear pinion bearings and the wheel axle bearings. The carrier bearings were Timken tapered roller and they were in the worst condition. The race of the cone had spalling in about on sq. inch of area and the rollers were toast. The pinion bearings were not so bad but one was Timken and one was Koyo. The Koyo looked the best. The axle bearings were Torrington. The axle bearings replacement has the benefit of a better ride. It feels tighter back ther now.

I am an engineer with Timken and will be cutting/inspecting the bearing components to determine if it was the case hardening process to blame or was it the metallurgy or possibly housing/shaft missalignment.

I had an honest mechanic do the work for a total of $300.00 including new front oxygen sensors which were slow to respond. I bet a lot of people are paying for complete diffy rebuilds and don't need them. My rear wine is no longer present.

 

[ford lover]

The bearings in the rear axle are the culprit. I had the whining sound coming from my rear end only when you stepped on the gas pedal. I had the outer axle bearings replaced and a bearing on the ring and pinion replaced and the sound disappeared. Total cost from neighborhood mechanic $430.00.

 

[GSEREP1]

I agree completely. Once the bearings are allowed to run without oil for a period of time, it ruins the bearings. Even if you put oil in later, it is then too late to fix it. Changing the bearings is the only answer. A GROWLING sound would also be gearings and GEARS that have a tooth either chipped or missing. Applying load puts torque on the entire assembly, and thus you get the whine.