fly boy_1

iTrader: (4)

So I have an MWC fab 9, and when I started driving yesterday there was a huge increase in gear noise from about 30mph on up which was not there previously. It has a bit over 500 miles on it so I thought it should be all broken in by now. The noise is only when accelerating not coasting or braking, and sounds different than the little bit of gear whine it had before. It just seems odd that it was quiet earlier in the day, then all of a sudden whines. Previously it had a little noise around 40mph, and again around 60, now it is constant and much louder over 30mph. Thoughts? Im not blaming anybody, just wondering if its normal or if I might have messed something up? The temp did rise recently and Im wondering if the tires hooking harder may have contributed to this?

wrd1972

iTrader: (12)

Check the fluid and if its ok, stop driving, pull the third member out and check the pattern cause likely something is out of wack.

fly boy_1

iTrader: (4)

Ok, that what I'll do. I put in some cheapo non synthetic 80w-90 gear oil as recommended, just over 3 quarts till the fluid was at the fill hole. Any ideas why it would do that all of a sudden and not from the get go? The mesh was all set by MWC. I'm gonna drain the fluid and see if there's anything in there.

I dont imagine it'll be low, I haven't seen any signs of leaks from the axles or anywhere else.

fly boy_1

iTrader: (4)

So I called MWC, and they advised me to drain the oil, which I did and its still clean with just a tiny bit of metallic residue on the drain plug which is normal since it's all brand new basically. They said to check the pinion nut and see if it came loose, and I'm imagining that's probably it. Not sure why it may have loosened though?

Monzsta

It could be a bearing race that wasn't fully seated moved under the heat and load, allowing the pinion or carrier to get out of adjustment. I'd pull the chunk and bring it back to who built it so they can re-set it up. It will need to have the backlash and preload set back up or it will eat the new gears and be forever noisy.

fly boy_1

iTrader: (4)

Yes that may be the case, I checked the pinion nut and it doesnt seem to have loosened up. I'm in contact with MWC about it, so far they have been very helpful!

fly boy_1

iTrader: (4)

Just to bump this thread back from the dead, I've sent the center section and gears in to MWC for them to inspect, and replace the gears and re set up. It had Yukon 3.89 gears in it, and I saw the other thread with MWC mentioned the guy was also using Yukon gears, so I'm wondering if there is a correlation there.

For a 9" rear, what do people feel are the quieter gear brands out there, I've read Richmonds are the loudest, how do motives or others compare? These Yukons were decently quiet until they failed.

wrd1972

iTrader: (12)

My Motive 4.11s are dead silent.

LS1-IROC

iTrader: (4)

Noise is a very subjective thing. Mine has Motive 4:11's in it and make noise from 40-60mph. It drives me nuts, others have rode in my car and say they are pretty quiet. LOL If you want a real quiet set of gears I'd recommend trying to find a set of used FoMoCo factory gears.

wrd1972

iTrader: (12)

Could not disagree more. If you want silent gears, you need a proper install. A proper install can mean lots of time and trial and error to get it right and there is no easier gear to set up than a nine. Most people can not read the patterns and even a pretty pattern does not promise quiet gears.

I ended up re-shimming several times to get the proper set up and again they are dead quiet. Being off on the pinion shim as little as .003" can create noise but the with the nine, all you do is pull the DS, then the pinion support, reshim and try it out.

Again setting up gears properly is very difficult and few have the ability to do it.

Monzsta

To add to this, I've seen the worst patterns (even burnt/blackened gears) be dead quiet and the most beautiful picture perfect patterns be like a screaming bag of cats. As I've said in other diff threads, it sometimes pays to be creative with clearances. Just because the book says .005"-.008" backlash doesn't mean .002" or .012" won't give you the footprint or silence you desire. The gears run the show, not the paper. If the gears get what they want, they'll be quiet in return. Fussy *** little premadonna bitches some of 'em are! lol!

LS1-IROC

iTrader: (4)

That's fine, and I agree that the key is set-up to ANY set of gears. Bottom line is factory gears will be your best shot at having silent gears...period. Not all gears are cut the same