Rear axle howling

Hi i just attempted to set up my rear axle for the first time. I have a 440 cuda with an 8 3/4 rear axle and i wanted to put 3.55s in it. I replaced all thepinion and carrier bearings, and the ring and pinion. I set up everything like the manual called for including pinion depth and preload, carrier bearing preload, backlash all to specs. When i checked the ring and pinion with marking compound, the marks seemed perfect, right in the center of the ring gear, The noise im hearing is not a loud howl and only really audible about 45 coasting, but then again the cars loud so it could be more consistant. DO you think i should put some miles on the rear end and see if it breaks in and goes away or do you think it should be taken back apart and redone? If you think i should let it break in, is a noise like this something i should worry about being an issue when i stomp on the gas and put real pressure on it?

 

The noise is just annoying....assuming you have a good pattern on the drive side of the gear teeth.

Are they new gears?

 

New gears and the marks looked good an the drive side

 

To the question about putting miles on it not only no but HELL NO. I don't really know what the issue is because ring and pinions is one area that I have very limited experience and I haven't set one up in over 40 years. There are certain things on a vehicle that no matter how good you are on the rest of the vehicle you load up and take said part to the expert and for me rear ends are that thing.

 

After a while i would want to see if it was eating itself up. If it gets louder it probably is. Open it up and see if there is metal in the lube and check if the set up clearance has grown. If the clearances are still set where you put them it is just an annoying noise. Then you'll know. Otherwise the gears are soft and eating each other.

 

also, the noise most likely will not go away....

Some brands of gears seem to require a different setup than the old manuals call for.

 

I'd pull it; check the preload on the carrier bearings to see if they are loose, then go on the tigher side of specs on backlash.

and check the wear and decell patterns again.

I'm thinking the carrier preload is gone...and too much backlash

 

I have had really a fight over the past 15 years trying to make the 9 inch in my sedan quiet. Alot of aftermarket gearsets are tough to get set up to run quiet but the factory gears seem to be much easier when using FACTORY specs.

The latest gears I installed I tightened up on the backlash to almost half of the suggested spec and the gears are absolutely quiet at all speeds. This of course is with a picture-perfect pattern and pre-load.

I don't recommend this kind of experimentation when installing gears (tightening the backlash that much) but I thought...what the hell, if it don't work I'll just pull it out and re-do it. The car has almost 10,000 hard miles on it with these gears so I'd venture to say that it hasn't hurt it any...or did I just get lucky???

 

I had a noise problem like this with new carrier bearings on old races, but that was a GM 12 bolt.

 

had a noise like that and it turned out to be coming from the transmission noise travels. do like the TV commercials and strap yourself under car and have someone drive you around - HA!

 

If you are confident in your work, and what the pattern should look like, then run it awhile, I don't think you are going to hurt anything, and you will know pretty quick if it is going to get better.

 

The 9 inch tracLock in my 27 howls like a mutha and it is a completely rebuilt unit. I thought it might be because it is a 4.30 ratio, but not so sure. It has done that since day one and I have a lot of miles on it without any problems so far.

I just keep the headers uncorked most of the time and don't have to listen to it.

Don

 

Richmond?

 

For noise on a coast, I'm more inclined to go with a carrier bearing adjustment.

Bob

 

I installed a lot of gears in 4x4's and I would explain to customers before I started that there could be noise. Not all gearsets are created equal. That is not to say they were bad. If you set it up correctly it is what it is. For peace of mind it wouldn't hurt to go through it again and check everything. The one noisemaker I saw most often was people putting new bearings in old races.

 

My experience with rear ends is that if they are set up right, you may just have to deal with the noise. Then again, I only run Richmond gears, and haven't had much noise to speak of.
As said before, run it a while then check the oil to see if there is metal in it. You might have to open up the whole thing to actually get a look at the magnet in the rear end, I know the newer Mopar carriers are that way. Worst case scenario, you need a new set of gears.