489 center sections...is this good price?

[djais1801]

i found a 8 3/4 rear 489 case 355 gear rebuilt $695, new $895 and 8 3/4 rear 323 gear for $450..

i currently have a 741 or 742, (not the weaker one) center w/ 391 gears...it sings at higher rpms/highway driving..
am i better off buying a 355 rebuilt for $695 rather than rebuilding mine?
how much "off the line" will i lose?
thks!!:headbang:

 

[RustyRatRod]

What kind of whine is it? If it is somewhat high pitched, it's probably associated with the pinion gear and somewhat low pitched moreso with the ring gear. It could be something as simple as the yoke nut backing off, of a bad small pinion bearing. Either would require minimal labor. I would say take yours to a shop and have them diagnose it. All 8 3/4 differentials are strong. Nothing wrong with a 741 case. If you're happy with the 3.91, try to stick with it. Fixing yours might end up being the least expensive thing to do.

 

[Bad Sport]

3.55 will be a little slower but shouldn't be huge, they are a good all around street gear. If you just need gears why not just rebuild what you have. I think it can be done for less than the 695.

I assume you are talking about RPM on the highway? If so a taller tire may be all you need. That will change the ratio some.

 

[djais1801]

it is only heard at constant hwy speeds, when i back off, it slowly goes away...it almost sounds like a "waa-waa-waa" like a flat spot in a tire would sound...no vibration, the rear pumpkin seal is seaping..
i have new tires, and it happens w/ the rallye rims, and the cop wheels i just bought. i am running 245 60's on front and 275 60's on rear...
i actually don't mind the gear ratio..it's a little annoying, i would like to take the car about 40 -80 min away for cruise nights/car shows etc. You just see the same stuff every cruise you go to locally.

 

[Bad Sport]

Ah, so it is noise that you have. Swap some new gears in if that's the case. If you do there are certain steps to take before, during and after when doing these.

If you have never done it, it's not bad but does require some special tools and some reading. I think when I rebuilt my center section it was around 300, gears, bearings etc give or take. Hell I rebuilt my entire rear for around 600 and that included the price of the housing which was 100 bucks.

 

[djais1801]

is this something that can wait? will it damage anything else if i wait?? Mostlikely, i will be just going locally for a few more weeks until she goes to hibernation

 

[Bad Sport]

IF it's just gear whine then no it won't hurt anything.

 

[RustyRatRod]

Gears don't "just" start making noise. Something makes them change position (bad bearing). You should get it checked out.

 

[Bad Sport]

Gears don't "just" start making noise. Something makes them change position (bad bearing). You should get it checked out.

Good point, but the OP didn't mention it just started, if so i missed it. If it was quiet and started making noise then I agree wholeheartedly.