Gearbox and Differential Oil Additives

Check:

Oil level to proper point

wheel bearings

Brakes

Tire wear/pressure

if the diff has an access cover or a drain that you can get a scope through, check the gears for wear.

Make sure you are using lubricant specifically for with or without positrac clutches. Whichever your vehicle is.

If you are sure the differential is hamburger anyway and the fluid is low viscosity like is common now, I may try thicker stuff like EP90 or EP140. This may put the bearings at risk but it might help with the sliding of the hypoid gears that may be the source of the noise. Any gains here would be temporary.

Hey there is always sawdust.

I forgot sawdust! The old dealership "cover up the funny noise" trick!

May the mechanical gods strike me down for that!

Nylon stockings work well for a while.

mix ep 90 with grease and put that in.

or just put grease in and let it mix.

What is floating on the golf surface? Your "thing" has been heavy duty tested for at least 4000 miles in Africa. G.A.

http://books.google.co.uk/books?ei=jRUYTNTSJs2A4QbVy9DZCw&ct=result&id=EpSrYt9lFLMC&dq=cures+for+noisy+differentials&q=cure+for+noisy+drive+trains&as_coll2=+issn%3A0161-7370+

http://books.google.co.uk/books?ei=jRUYTNTSJs2A4QbVy9DZCw&ct=result&id=EpSrYt9lFLMC&dq=cures+for+noisy+differentials&q=cure+for+noisy+transmision&as_coll2=+issn%3A0161-7370+

http://www.differentials.com/diagnose.html

http://forums.mercedesclub.org.uk/archive/index.php/t-18083.html

http://forums.bimmerforums.com/forum/archive/index.php/t-429310.html

http://www.google.co.uk/search?hl=en&rls=com.microsoft:en-gb:IE-SearchBox&rlz=1I7GZEU_en&q=ring+and+pinion+noise&revid=1798357948&sa=X&ei=SBcYTL7fB4n40wTJvazQCw&ved=0CEgQ1QIoADgK

oils etc

http://www.google.co.uk/search?q=oils+for+noisy+transmisons&sourceid=ie7&rls=com.microsoft:en-gb:IE-SearchBox&ie=&oe=&rlz=1I7GZEU_en&redir_esc=&ei=BxgYTJvtO6ay0gSj6vXECw

oil treatments

http://www.google.co.uk/products?q=nulon+engine+treatment&rls=com.microsoft:en-gb:IE-SearchBox&oe=&rlz=1I7GZEU_en&redir_esc=&um=1&ie=UTF-8&ei=dBgYTJTQC5Ki0gStnLHHCw&sa=X&oi=product_result_group&ct=title&resnum=11&ved=0CFsQrQQwCg

BE CAREFULL WHAT YOU PUT INTO DIFF AS IT MAY CAUSE PROBLEMS IF YOU HAVE AN ACCIDENT AND MORE SO IF ACCY WAS CAUSED BY DIFF !!!!!!!

Lyn i Know my caps lock was on,

It wouldn't be the first time someone decided to overhaul a differential because of noise they THOUGHT was coming from the rear end. Unless you have checked thoroughly and confirmed that the noise is coming from the rear it would be prudent to actually get under the vehicle safely supported on jack stands with the driveshaft turning in gear and either use a stethoscope or long screwdriver and actually confirm the noise is coming from the differential. Keep in mind all gears make some noise, but if they are defective or the bearings are bad you will at least be sure of the source of the noise. Don't know if your vehicle has a manual trans, if it does an output shaft bearing can also travel thru the driveline to the rear of the vehicle. Do it right the first time! Good luck,

h

Testing, or checking is definitely the right procedure, but in this case, there is no good way to check all conditions while on a set of jack-stands.

Proper lubrication is advantageous when used to prevent damage of mechanical mechanisms though the practice will not correct the damage issues after the fact.

You know that Slick ptfe stuff you can get, well if ptfe is so good why not try buying ptfe tape that plumbers use, cut it up into strips and insert the strips into the diff.

if you try this let us know what happens, as you are going to strip dif anyway it would be good to see what it looks like after you have run it for a while.

like mission impossible if it all goes pear shaped ( and whats wrong with a pair) i will say i know nowt.

Using a fine cheese grater and a block of PTFE produces a better matrix

Most things have been mentioned by others- is the whine at a steady load or on decellaration- on all road surfaces?- synthetic gear bearing oil is said to be 5x longer lasting than mineral oil- in the old days we adjusted diff gears using red lead as tooth mesh indicator by shims- if whine is at steady mph then fades above/below likely to be wear on pinions( if vehicle has been driven at a certain speed most of life)- so yes recon/replacement is best option- check out vendors- lots of sharks out there!.

Hi all.

Thanks for all those suggestions and links. Not so sure that the stethascope/screwdriver idea will work so well at 60mph. The noise is definatly the diff. It's always the same, it starts quietly at 50 mph and peaks at 60mph and is gone by 70mph. It's a bit quieter with a load but that maybe just because the load is filling the cargo area and absorbing the sound. It was like it when I bought the van, I can't remember hearing it when I test drove it, but now I remember seeing a couple of thick rugs laid out in the back!

A good thing to remember that when you have the vehicle up on jack stands ,engine running and in gear , when your speedometer reads 30 mph the differential is going 60 mph and it is not recommended to exceed 30-35 mph on the speedometer.

h

On RWD vehicles using the diff there are two adjustable bearings on the input shaft; one forward an one aft.

If I recall correctly the rule of thumb was whine on acceleration was due the forward bearing being out of adjustment and whine upon deceleration the aft out of adjustment or vice verse. This adjustment is of the slack in the input shaft bearing assembly.

Why don't you try some dry teflon powder (PTFE) Hoppes do a small bottle of it and it's micron grade so there will be no problem with it mixing and coating your gears, I added a load to my discovery gearbox with fantastic results

WHOAH There!!! I'm just going to check I've logged on to the correct website...... Yep it's definately the CR4 ENGINEERING website... So whats all this talk about grease, sawdust, stockings and goddamn Banana skins?!!!

You would use the banana and eat the skins yourself? No logic in that.

There is more to that diff than just two gears. There are wheel bearings, axle bearings, pinion bearings, and of course the ring and pinion gears. All have noises associated with them.

Wheel bearings are not very sensitive to acceleration or coasting loads, but are sensitive to weight loading on turns. Try to find a wide safe parking lot, or open road. Do long slow curves from left to right side of the road, then back. A wheel bearing will be louder when the weight shifts to that side, and quieter as soon as you unload that side and shift to other side.

Pinion bearings are sensitive to acceleration and coasting loads. The test for these is to try to maintain the same speed while alternating between on and off throttle. That should bake the noise louder and softer in relation to your right foot.

Axel bearings, or carrier bearings are more difficult to diagnose from noise as they are sensitive to both of the above tests, but to a lesser extent. So if the above two tests leave you confused as to why both seem to work, it may be the axle bearings.

The bad news is that axle and carrier bearings all are used to locate the ring and pinion gears to very exact positions. And if there was a bad bearing that was allowed to be driven for any length of time, you may have worn the ring and pinion to the point that the gears themselves will always sing.

SOOO, if you have replaced the rear tires with other ones, and have ruled out wheel bearings, think about having the entire ring and pinion assembly replaced along with new bearings. Or replace with a junk yard rear axle assembly. The precise work required for proper ring and pinion replacement is not cheap, and most rear axle assemblies will live a long live without problems, making then in expensive in junk yards. Good luck.