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Differential howl, UPDATE

Posted By: Von

Differential howl, UPDATE - 09/11/08 03:17 AM

What exactly causes differentials to whine? Mine howls so bad, coyotes were following me home last night.

Seriously, I noticed when I put it in, it appears to have a lot of backlash. Could that be the cause?

Thanks
Posted By: Cudajon

Re: Differential howl - 09/11/08 12:14 PM

Von, it would really help if you explained what kind of rear end your talking about, but lets assume its an 8 3/4. The pinion was probably not installed correctly with the crush sleeve being torqed to proper specs. This allows the pinion to tighten up changing the alignment with the ring gear (backlash). This is why most rear end rebuilders use a spacer on the pinion and toss the crush sleeve. This is a common problem. There are other reasons the rear end can howl but this is most likely on a new setup.
Posted By: bobby66

Re: Differential howl - 09/11/08 12:21 PM

Might check the end-play on the axles, too. Maybe they just need adjusting.
Posted By: Von

Re: Differential howl - 09/11/08 06:32 PM

Quote:

Von, it would really help if you explained what kind of rear end your talking about, but lets assume its an 8 3/4. The pinion was probably not installed correctly with the crush sleeve being torqed to proper specs. This allows the pinion to tighten up changing the alignment with the ring gear (backlash). This is why most rear end rebuilders use a spacer on the pinion and toss the crush sleeve. This is a common problem. There are other reasons the rear end can howl but this is most likely on a new setup.



Sorry about that, it is an 8 3/4.

The chunk is not new. I had it set up 15 years or so ago. I dont remember it howling so bad before.

I did pull the yoke off and used it on another chunk? Maybe I didnt get it torqued right??
Posted By: Von

Re: Differential howl - 09/11/08 06:33 PM

Quote:

Might check the end-play on the axles, too. Maybe they just need adjusting.


They are aftermarket axles with green bearings.
Posted By: 540challenger

Re: Differential howl - 09/11/08 06:49 PM

Which case do you have??

489 have a crush spacer it should be replace everytime you have the yoke off.
Posted By: Pacnorthcuda

Re: Differential howl - 09/11/08 06:54 PM

Quote:

Which case do you have??

489 have a crush spacer it should be replace everytime you have the yoke off.



and on that note Von--IF its a 489 case I would be pulling it immediately and inspecting. If the teeth still look good I would re-install with the available non-collapsable spacers. The howl may be from a destroyed pinion bearing, or it may be the ring an pinion itself. You will most likely be able to tell. I would not continue to drive it.
Posted By: Cudajon

Re: Differential howl - 09/11/08 09:25 PM

If you want to save the rear end I'd spring for bearings all the way around and use the spacer instead of the crush sleeve..
Posted By: dogdays

Re: Differential howl - 09/11/08 09:35 PM

In my humble opinion, once the gears start to be noisy you might as well replace them because they are never going to be better. Hypoid gears mesh in a very particular way. New bearings, a spacer, and new gears are probably required to make things right.

R.
Posted By: Von

Re: Differential howl - 09/11/08 10:02 PM

Quote:

Which case do you have??

489 have a crush spacer it should be replace everytime you have the yoke off.



It is a 489 case.

The howling is more noticeable when decelerating. It barely makes any noise under load, but screams when you lift.
Posted By: a493demon

Re: Differential howl - 09/11/08 11:52 PM

pinion bearing or sleave like said before. brad
Posted By: dave571

Re: Differential howl - 09/12/08 03:20 AM

Quote:

In my humble opinion, once the gears start to be noisy you might as well replace them because they are never going to be better. Hypoid gears mesh in a very particular way. New bearings, a spacer, and new gears are probably required to make things right.

R.



This is correct. Typically when a gear set that has been run for some time starts to howl, it always will.

You can try doing the set up over again, and get the pattern text book. BUT even if you do, you've changed it from what it was, so it could even howl worse when your done.

If it's really bad now it's worth a shot.

Are you sure the pinion has a lot backlash, and not a lot of endplay? Endplay would mean the peload is no longer there. (bearing failure, or problem with the yolk install.

The pinion gear walking in and out can cause damage to the gear set also(back to replace the whole smear)
Posted By: TJP

Re: Differential howl - 09/12/08 05:10 PM

Quote:

Quote:

Which case do you have??

489 have a crush spacer it should be replace everytime you have the yoke off.



It is a 489 case.

The howling is more noticeable when decelerating. It barely makes any noise under load, but screams when you lift.



Based on your description I will say that your pinion bearing pre load is loose probably due to the yoke swap. On deceleration, by design, the pinion will be pulled into the ring gear IE: if it's loose, the ring gear will pull the pinion gear into the case and throw the centering of the gears off with respect to each other off and hence you will get lots of noise.
Crushing a new pinion sleeve is not easy in the car and going too far which is easy to do will result in the bearings being too tight. So once the sleeve starts to collapse go very slowly until you achieve the desired pre load. Or go with the solid spacer kit and shim it
Iif you get the situation corrected the gears may be fine with possibly a small amount of noise on deccel. Only getting the preload right will answer that question.
Good Luck
Tim
Posted By: Von

Re: Differential howl - 09/30/08 05:45 AM

Finally got a chance to pull my third member out. The pinion bearing looks OK, but the inside edges of the ring gear almost look like they have blued, The edges are also slightly rounded.

Does that sound like the result of taking the yoke off without installing a new sleeve?

Also, by my poor description of the above, will the gears live, howl, etc?

Thanks
Posted By: Gas_Bandit

Re: Differential howl - 09/30/08 01:08 PM

I bought a rear from someone once that had 4.56s in it (8 3/4) and it had the most horrible howl ever. Same thing, edges of the ring gear teeth were rounding off. This tells you your pattern is WAAAAAY off. If you run gears for any length of time with the pattern not set up right, you are never going to get the gears to set up and run quiet again. There is no way you are going to get gears grinding on the edges of each other quiet again. New gears time.
Posted By: JohnRR

Re: Differential howl - 09/30/08 01:12 PM

Quote:

Finally got a chance to pull my third member out. The pinion bearing looks OK, but the inside edges of the ring gear almost look like they have blued, The edges are also slightly rounded.

Does that sound like the result of taking the yoke off without installing a new sleeve?

Also, by my poor description of the above, will the gears live, howl, etc?

Thanks



How did you check the pinion bearings ? Did you disassemble the chuck ??

But I agree your pattern is WAY off from the sounds of the ends bluing , did you run a pattern check when you pulled it out ?

Will it still howl , how long have you run it like this ?
Posted By: Von

Re: Differential howl - 09/30/08 03:16 PM

[quote

Will it still howl , how long have you run it like this ?



About 100 miles.
Posted By: CokeBottleKid

Re: Differential howl - 09/30/08 03:23 PM

Quote:

I bought a rear from someone once that had 4.56s in it (8 3/4) and it had the most horrible howl ever. Same thing, edges of the ring gear teeth were rounding off. This tells you your pattern is WAAAAAY off. If you run gears for any length of time with the pattern not set up right, you are never going to get the gears to set up and run quiet again. There is no way you are going to get gears grinding on the edges of each other quiet again. New gears time.



if they didn't whine before you probably didn't torque the pinion correctly .
Posted By: 6PakBee

Re: Differential howl - 10/02/08 01:08 AM

I'm not going to disagree with anyone but this is the one experience I've had with this. Bought a W200 with the 4.10 Dana 60 in it. Drove it 500 miles home with the rear end singing the whole way, both on acceleration and deceleration. After about three months I finally crawled under it and found the pinion end play to be over 0.050" (that's no typo). I set the entire rear end up again from ground zero and drove it. Now it sung on deceleration but not acceleration. After about 50,000 miles it's quiet in both cases.
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