Rear End Noise on an 8 3/4

[dvnen]

After many years of sitting, I started driving my car again and notice that I am getting a "howling"/"whinning" noise from the rear end?  Any thoughts on what it might be or if there are things that I can begin to check for myself.  Also, there are 4:10 gears in the back now and I was looking to replace with 3:55 or 3:73 gears.  Are these available from an aftermarket supplier, and if so any quesses as to the cost to purchase and have them installed.  Thanks..

[Chatt69chgr]

I don't know how to diagnose the howling but would assume it's the ring and pinion although it could be a rear bearing.  You might put the car up on stands and let the rear rotate and use a stethescope (but be real careful).  The best place I found to get the ring and pinion were from Strange Engineering for $189 plus s&h.   Made in USA by them in Chicago.  Easily beat Randy's ring and pinion.  They were the highest place of all.  Guess it costs a lot for those ads of theirs.  They have everything from 3.55 up.  I got all my bearings and seals from AutoZone.  They have Timken tapered roller bearings. 

[cool440]

Change the gear oil and DO NOT FORGET the limited slip additive. 

[74Charger]

Check your axle bearings.  I had a friend recently that was getting a howling from his rearend.  Turned out that his bearings were totally worn out.  I bought all my stuff from Moser and Strange.  Sometimes some of the gear sets are out of stock.  Make sure you know what case you have before calling also.  It should say on the side of the drop out third member.  Either a 742,741 or a 489 case.  If its a clutch type sure grip.  Now would be the time to get a rebuild kit, if it needs it. And if you still have left handed threads.  Now would also be a good time to switch those over or just plain get new ones.


http://www.strangeengineering.net/catalog/index.html

http://www.moserengineering.com/Pages/Ring-Pinion/ringpin.html

The easiest thing to do if you do change your gears.  Is to buy the complete setup kit.  And get the green bearings.  Take it down to a good shop that knows what they are doing.  And you should be good as gold.  Make sure it is a reputable shop.  The last thing you want to do is change it out.  And still have a rearend that howls.  Or a backlash that is off.

[John_Kunkel]

Does the rear end noise change throttle on/ throttle off? How about when swerving from side-to-side?

[dvnen]

thanks for the replies...is changing the bearings a relatively inexpensive job, or should would it make sense on changing the rear end gears at the same time to save costs. 

Regarding the noise -it ususally starts at 20 mph and continues all the way up.  The noise is constant despite the side to side motion. 

Thanks

[74Charger]

Yes the bearings are fairly inexpensive.  And pretty easy to get at.  Should cost you somewhere around $100 if I remember right.  That should cover the bearings along with having someone take them off.  And press new ones on.

If it was me.  And was considering changing gears anyways.  I would do it all at once.  and yes it will save you time and money.  One shot deal.  Gears, bearings, setup kit, and check the suregrip, rebuilding if necessary.  You will be glad to know its done right.   

To check the bearings we jacked up one side of the car and spun the wheel.  You could hear the bearing scraping.

One other thing, I thought of.  Is if you have the older bearings they are preloaded.  (Ithink thats the right terminolgy)  And also adjustable from the passenger side axle.  They could be out of adjustment.  Not sure if that could cause the rear to howl.  But might be worth checking into.  Someone will help me out here if I am wrong.  I never really had to mess with those as I have green bearings.  And you do not have to worry about that.

[71 Bee Man]

After many years of sitting, I started driving my car again and notice that I am getting a "howling"/"whinning" noise from the rear end?  Any thoughts on what it might be or if there are things that I can begin to check for myself.  Also, there are 4:10 gears in the back now and I was looking to replace with 3:55 or 3:73 gears.  Are these available from an aftermarket supplier, and if so any quesses as to the cost to purchase and have them installed.  Thanks..

Just briefly because I'm about to walk out the door......I recently had exactly the same problem - thought the diff was on the way out and had this whine which occured on decelleration. Gradually got worse till I thought it was coming through the floor.

It was a loose pinion nut - the one behind where the tailshaft and uni joint bolt on - real big nut.

Have you checked that ?

Peter

[Chatt69chgr]

Mother Mopar used Timken tapered roller bearings for the axle bearings.  They do have an adjustment on the passenger side to set the preload.  Similar to adjusting the preload on the front wheel bearings when you tighten the spindle nut.  Tapered bearings are designed to handle side loading----like when you go around curves.  The green bearings are sealed ball bearings.  Drag racers use them because they mostly go in a straight line.  They are really not designed for side loading.  A set of properly adjusted tapered bearings should last for a very very long time.  I don't know what the life of the green bearings are.  Probably a lot more than any of us will ever drive these cars.  And they are sealed lubrication wise which is nice.  So there are pros and cons to each type.  The choice is yours.