Gears & Axles - Just got 373's, Horrible Whine!

Ok guys, i just got back from my local shop, and they put new gm motive 3.73's in my 98 a4 z28, i had them put in a brand new eaton posi and all new bearings, and these gears REALLY whine whenever i let off of the gas! I mean it sounds like an airplane! But its a very reputable, BIG shop, that's actually on this site (keeping name anonymous). They said it was normal, but i don't understand, because people always say if their set up right, their should be no whine! What should i do? Is it normal to have a really loud whine!? Or should i take it elsewhere?

on a 3.73 no it should not whine if done right ......i have 4.56's and they whine a little but there bigger gears ....

If it whines on decel only there is not enough preload on the pinion bearings. You can tourq the pinion nut down until it goes away or have them do it.

Motive and AAM are two different companies by the way. AAM makes GM gears.

I had a similar problem when I had gears put in. When I let off the gas they would whine like no other, it turned out the pinion nut had loosend.

I just had 4.10 gears installed in my A4 and they have the slightest whine when you are giving it partial throttle at a cruise speed. If you are accelerating you cannot hear it. If you have your foot off the gas you cannot hear it. It also is not loud whatsoever. You can barely hear it. It sounds like a baby supercharger. :D You really have to listen for it to hear it.

I have Motive Performance gears. I heard the Motive standards are one of the loudest gearsets. However, they should not be obnoxiously loud like you are describing. It sounds like there is a slight problem with your install and i'd have them crack it back open and re-check everything before you continue to drive on it. You may cause some damage to your rear end if you are driving on them when they aren't properly installed.

[QUOTE]They said it was normal.[QUOTE]

They shot you bullshit. I just had 3.90's installed that were quiet until I punched it at 500 miles. My car is in the air now because I'm getting new ones installed. They had the slightest whine on decel when I went to pick it up and I didn't accept it because I'd just had quiet gears the previous week. If they are a Big Name shop, then they shouldn't shoot you crap. If they don't fix it. Call them out on this board but in the feedback section. We're supposed to be a community to help one another. So, the mods shouldn't band you if it's all true.

I just picked mine up yesterday after a 3.73 gear install and im in the same boat...The rear is howling extremely loud after letting off the gas....The installer is a very reputable sponser on this site as well. I was expecting a small amount of noise but this is unacceptable...i can hear it over the radio. It sounds like the rear is going to fall out of the car when you let off the gas. After picking it up and driving down the road i turned around and the owner told me "they were hardened gears and they were setup correct and thats normal noise" :eyes:

Ive also got the Motive Performance 3.73's. I had an issue with the whine at first but after asking several different people I was reassured that nothing was wrong and it was normal. I told my tuner about it and they told me that the motive gears always whine when their installed into the 10 bolt 7.5.
Mine really isnt whining the bad at deccel. But does whine a little louder around 75mph when pressing the gas.

Also after I went my 500 miles i drained the rearend to check things out and checked the fluid and it was clean as a whistle. NO SHAVINGS


Im using the stock 90 weight but I heard a little thicker gear oil will quite it down some. Im not sure though havent tried it. Any tried it? tap in and let us know if it worked.


sean

AAM next time

[QUOTE]They said it was normal.[QUOTE]

They shot you bullshit. I just had 3.90's installed that were quiet until I punched it at 500 miles. My car is in the air now because I'm getting new ones installed. They had the slightest whine on decel when I went to pick it up and I didn't accept it because I'd just had quiet gears the previous week. If they are a Big Name shop, then they shouldn't shoot you crap. If they don't fix it. Call them out on this board but in the feedback section. We're supposed to be a community to help one another. So, the mods shouldn't band you if it's all true.

So what are you gonna do then? Let me know.

torque the pinion nut a 1/4 turn

[QUOTE=RealLiveMD;9495462][QUOTE]They said it was normal.

So what are you gonna do then? Let me know.

My car's still at the shop. The guy closed the shop to go racing. Anyway, he knows I'm not accepting whining gears because I just paid $600 and he had the gears perfect until after the 2nd gear WOT run. Now, unfortunately, I'm paying an additional $400 for a guarantee that he will replace them for free if they whine. I'm getting it in writing. He said that he wouldn't honor it the first time because I bought the gears. This time everything is being bought through the shop. I know he's gotta be getting pissed my rear end has been out 4 times now.

should NOT whine on decel...it will most likely whine a bit at various rpms..

ok, i brought it back there today, and the called me and said everything was set up right. They told me, when I called them, that they torqued everything to spec, and said theyve done over 1000 gear installs, and i dont doubt them. they think the motive gear was machined wrong and their about to send it back. Has anybody else heard of having gears machined wrong, and have had this happen to you?

What color box did you buy? Was it blue or orange? As an aftermarket gear we will never garuntee a quite ring and pinion even though most of the time the Performance gears are not a problem. Hard to say without seeing the gear.

Sounds like the pinion bearing if its on decel.

ok, i brought it back there today, and the called me and said everything was set up right. They told me, when I called them, that they torqued everything to spec, and said theyve done over 1000 gear installs, and i dont doubt them. they think the motive gear was machined wrong and their about to send it back. Has anybody else heard of having gears machined wrong, and have had this happen to you?

I'm on my second set of 3.90's. The first gear I've yet to send back to the manufacturer although you can clearly see how the gear was alligned fine and something moved. The installer says that it had to be the gear because everything is torqued right. Now they're on the second gear. It's clear that the gear is set up right on the drive side, if they move it, then it will become quiet on the coast and whine on the drive. They've been trying to get a call back from motive for 4 days. No luck. It always goes to some guy named Anthony' s voice mail. Anthony hasn't called me back; and, I called over 2 weeks ago. Good luck. I wish that I'd never touched the rear.

Just a heads up to the O/P---alamantia was correct...mine was the pinion nut wasnt torqued properly...you could move the yoke up and down slighly by hand (installed by a sponser in the northeast aka professional:eyes:)I had to go one full rotation on the nut and it quieted the gears down to an acceptable noise level (alittle whine but bearable) Im going to get in touch with the owner of the shop and let him know that they werent installed properly in the first place.

Got my car back today too. The shop had to put the 3.42's back in. He couldn't get it right. He did give me the labor cost back though. I really wish I could have had him check the pinion nut before he removed my 3.90's. I bet it was the same problem.

A lot of factors can contribute to this issue...


How long did the break-in period last? Did you start pounding on the gears within the first 100 miles?
Was a solid pinion spacer used, or a crush sleeve? I'm guessing that since the pinion nut backed off, it was probably a crush sleeve.
If a crush sleeve was used, did the shop place a small weld bead on the pinion nut to ensure that it wouldn't back off?
When you were under the car, did you take the cover off to take pics of the gear pattern?

A lot of factors can contribute to this issue...


How long did the break-in period last? Did you start pounding on the gears within the first 100 miles?
Was a solid pinion spacer used, or a crush sleeve? I'm guessing that since the pinion nut backed off, it was probably a crush sleeve.
If a crush sleeve was used, did the shop place a small weld bead on the pinion nut to ensure that it wouldn't back off?
When you were under the car, did you take the cover off to take pics of the gear pattern?


Not sure if you were responging to me or the OP. I did see my pattern change after the 500 mile break in period. And They use a crush sleeve and loctite on the pinon bolt. The odd thing is, I hammered my O.E. 3.42 in his parking lot after he'd just put them in. No whine, no noise. However two different 3.90's and one 4.10 from motive howled like a wolf. I'm starting to believe that it's actually in the gear.

Im Tired Of Re Doing My Gears It Seems Like It Just Gets Worse Every Time !!!!!!!!!!!!!!!!!! Has Any One Got There Gears Done And Not Have A Problem If So Tell Me Where So I Can Take My Car............

Mine had no whine for 200 miles until I punched it and then I got a little whine on coast pinion nut loosened? Whine was less than my stock 2.73. Keep in mind, I have a frame mounted T/A which allowed for my oem 2.73 to whine.

i had 2.73 and had motive 3.73 put in. i would say it whines just a tad bit like others have said when decel.

Old thread eh?

A lot of factors can contribute to this issue...


How long did the break-in period last? Did you start pounding on the gears within the first 100 miles?
Was a solid pinion spacer used, or a crush sleeve? I'm guessing that since the pinion nut backed off, it was probably a crush sleeve.
If a crush sleeve was used, did the shop place a small weld bead on the pinion nut to ensure that it wouldn't back off?
When you were under the car, did you take the cover off to take pics of the gear pattern?


1. are you saying premature rough housing the rear end can actually cause whine after it was previously silent??
2. 10 bolts use crush sleeves
3. weld the pinion nut to what exactly? the shaft of the pinion gear? bc that would ruin the threads.

i installed some 4.10s two weeks ago and set the pinion drag at 30 inch/pounds with a .006 backlash while reusing all the factory shims and after about 200 miles it is dead silent ( Motive stock replacements). this rear had LOUD noise on decel and although the pinion bearings may have been at fault the only bearing to show any wear was one carrier bearing that chewed the shit out of the race. i got some Motive Performance 3.73s going in mine with .007 backlash with 30 inch/pounds of pinion drag, so i will let everyone know how that turns out.

EDIT: just took my first spin with my 3.73s and not one hint of noise. i will be going easy for at least a couple hundred miles......:secret2:

1. are you saying premature rough housing the rear end can actually cause whine after it was previously silent??

That's what I've been told. :) I'm not sure what the exact process is that happens during break-in. It might be something to do with the contact surfaces of the ring and pinion... but I'm the wrong person to ask about that.

In a nutshell, I think that if gears are installed properly in a street-driven car that never sees the track, you can probably expect them to remain quiet. I think what kills them are wheel hop and hard launches.

2. 10 bolts use crush sleeves

From the factory, yes. But Ratech does make a solid pinion spacer. (See here (http://speed-eng.com/store/ratech-solid-pinion-spacer-crush-collar-wshim-kit75-bolt-p-10013.html)).

3. weld the pinion nut to what exactly? the shaft of the pinion gear? bc that would ruin the threads.

When Speed Inc. installed the 4.10's in my 10-bolt, they put a single tack weld between the pinion nut and the threads of the pinion. When I grenaded the rearend a few years later, it was easy enough to grind off the weld bead with a quick brush from my grinder. The threads were certainly messed up after that, but I think that's one of the only ways you can really secure the pinion in these cars. It seems like a good hard launch will deflect *something* (I'd guess the pinion), which seems to compress the crush sleeve and screw up the tightness of the nut.

It seems like a good hard launch will deflect *something* (I'd guess the pinion), which seems to compress the crush sleeve and screw up the tightness of the nut.

well i certainly agree with that. the rear i put 4.10s in was a 100k 10 bolt that was living a quiet peaceful life, then a couple hard launches at the track on street tires is all it took to make it start howling terribly. it howled on decel.

My motive 3.73s were quiet for about 35 miles, then the pinion nut backed off a smidge. Got a loud whine, limped it home, retightened the nut and now have a slight whine on partial accel (queit on hard accel/decel). Makes a clunking sound under heavy accel in 1st gear only, but I'm pretty sure that's the diff going out (maybe just wheel hop??). Gears looked fine at 500mi.

I told my tuner about it and they told me that the motive gears always whine when their installed into the 10 bolt 7.5.

sean

Not true, my motive 4.10's are very quiet.

Ok, I'm posting under my kids name. You are all fucking wrong, no gears make any noise if set up right, and if you tighten a pinion nut that is not loose you will burn up the bearings. I do one rearend a week, and have for 30 years. I have 5 LS1 cars and they are all quiet, 7.5's are the hardest to do, but they can be done right. Anyone that tells you low gears are noisy doesn't know how to set them up properly. The 4.30's in my Firehawk are quieter than the factory 3.42's. My kids 3.73's and 4.10 cars are quiet. If I do a rearend and I can not make it right I do it for free. I'm in St. Louis if you want me to do them correctly for you.
thanks Paul

I just picked mine up yesterday after a 3.73 gear install and im in the same boat...The rear is howling extremely loud after letting off the gas....The installer is a very reputable sponser on this site as well. I was expecting a small amount of noise but this is unacceptable...i can hear it over the radio. It sounds like the rear is going to fall out of the car when you let off the gas. After picking it up and driving down the road i turned around and the owner told me "they were hardened gears and they were setup correct and thats normal noise" :eyes:

Mine do it too..Its does it bigtime at decel,but also when around 20-30 mph..But.. did you go from 2:73 - 3:73..I did,I had to get the thick gears and they said that is why it does it..

i went from 2.73's to 3.73's as well. After mine were installed they were pretty quiet, for richmonds, but after about 1000 miles it started to howl incredibly loud. I checking it out and the pinion nut backed off. Tightened it up and not its queit on decel.