Is this a common or even feasible cause of rear end whine? I really hope so, this is my 2nd 8.8" that's made this noise. It's a constantly-increasing gear whine. (Increasing with wheel speed, that is) It's most evident under moderate acceleration. Hard acceleration and it quiets down (or the exhaust speaks up?). You also notice it on deceleration with the car in OD, even louder in D, you get the picture. This rear end's been sitting for a few years and I'm hoping maybe it's just lost some of the fluid through the vent or something because I paid a LOT for it. I wasn't patient enough to check the fluid level at all since I've had the axle... yeah, dumb I know. But I'm wondering if I dump it out and put some 75w140 in it if I might notice a difference? Oh, it also has 4.10 gears too.... are they just a noisy breed?
I doubt the gear lube would cause the problem, maybe if it was extremely low(which means you've likely already hurt it)...
Probably the gear wasn't set up properly to begin with... My original TC 3.73 gear has approx 140K mi and more than a few drag strip passes, still perfectly quiet..
Well, , then. I think I'm still going to change out the fluid and put a new bottle of friction modifier in it just to be safe. The rear end should get me through the rest of the year.
So, assuming these gears aren't set up right (backlash and all that) what kind of damage/failure should I expect? Is it just going to get louder and louder? Or is it going to snap really loud one day and take a part of the housing with it? I hope not because it's the '88 XR7 style rear with big drums & all that.
The rear end in my car has whined since day one.(pretty loud too) I guess I just got used to it after 18 of driving it. (my stereo is a lot louder) Only does it in OD. I thought they all did that until I read some posts a while back
Could be the pinion bearing. It failed in my old Toyota 4X4 and did exactly what yours is doing - whining only under moderate acceleration (mine eventually got to the point it rumbled during deceleration, too).
Might also be wheel bearings...
If it's not setup properly likely the whine will get louder as time goes on(gears wearing)... Unless it's making some clunks or clanks(yes they are different), I doubt it will have a sudden failure...
I had a '78 Chevy Malibu that whined... One day I decided to replace the the leaking front pinion seal... Guess what??? Nut was loose on the pinion... Repl seal anyway(found leak was coming through the yoke and from under the loose nut)... Put it back together with nut snugged up, never whined again...
The most common cause of rear end whine is a bad contact pattern on the ring and pinion. This is caused by, as TurboCoupe50 said, bad set-up. Incorrect backlash, or incorrect pinion depth will make noise. A pinion bearing will usually be very loud, and make a whine with a grinding pitch to it. Since the rear end you are talking about has 4.10s, we know that the ring and pinion has been replaced, so there is a really good chnace that a "Billy Bob" shop just installed the gears without setting them up properly, because that would take too much time and effort.
And this rear end was supposedly out of a 12-second car...
can you provide a BOM on whats required to set them up properly to include all tech pub references real quick.
BTW,, ill be down in pompano beach fl (3 sites) and pensacola Fl (six sites) last week of this month and a first week of next month.
gears are a PITA to install right IMO
I hate rear end work, setting up the shims and checking the back lash
rear end in my mustang(4.11's) whine like CRAZY once you get driving. Mine are shot, to many miles, and my father had bought them used, so we dont know if they were abused before. But anyway, the point is, they will whine, and the whining will get louder. If it gets like my stang, invest in some REAL good ear plugs!! My car leaves my ears ringing four hours they whine and howl so bad
Its easy work shimming up rears. hell you dont even need a mic or anything like that, but then again its not like you know anything about tearing rear ends apart and putting them back together. since you claim youve been doing this forever and youre younger than me.
now, Brian the old 7.5 in the bird used to whine and grind I had to much play in the carrier.mine was bad you might have yours too tight.
I never said anything like that. I have pulled them apart before,and put them back together, but never changed a gear set, just replaced the whole carrier. and don't you need a meter to properly set the backlash?? Rear ends and transmissions are my soft spots, I am still am learning about them.
Sorry I sound like a know it all, I dont try to..
This one feels a little loose as well. Ya know, let off the gas and there's that split second of 'free fall' then you can feel the drivetrain grab again. I hope it can be resolved with a new set of gears installed properly by a pro. I guess I paid too much for this rear end and assumed it was in good shape.
Forgot to add, though... man 4.10's make the stock 5L in this car feel powerful. Slightly improved acceleration ftmfw. Either that or I've been driving my econobox too long.
That makes it even more likely that it is set up wrong. You see that a lot, someone gets all wrapped up in trying to go fast cheap, and don't care if the gears whine or not. It doesn't really damage anything, its just annoying.
http://www.mediafire.com/?e2v2hzma7zn
for complete Ring & Pinion setup.
If you don't have access to the pinion shim set up tools, use the original shim as a guide, install the big pinion bearing, install pinion, check backlash, and adjust as necessary. Like this http://www.mediafire.com/?izz5m9bydn9
Yes, you use a dial indicator to set backlash, unless you can measure .008-.013" with your hand. Use a micrometer to measure pinion and carrier shims because the size markings usually wear off. If you replace the carrier, its a good idea to reset the backlash at least, due to machining differences.
I did mine in my SC and it wasn't that bad. It was more fun taking it out than anything else. I got a dial indicator from Harbor freight with a magnetic base, a 8.8 rebuild kit and a couple of seals. Its probably a much bigger PITA when you have a solid axle. Mine is nice and quiet but the U Joints I didn't replace are now starting to clunk.
-dz