LT_WON

Just got a set of 3.73 gears from motive installed today. Moved from stock 3.23's . I'm getting a little whine when decelerating. Is this normal? Any tricks to quiet this down a bit or does it go away a little with time. Also is a tune required after this mod. Feels like I lost a little low end power. Any help willl be great.

Leeroyws6

iTrader: (4)

who installed them? doesnt sound like they installed them properly.im in fort wort also.curious to know who installed them.

Silver Sleeper

iTrader: (7)

sounds like the backlash is off a bit. was there a measurement and runout check done when the gears were installed?

Ethan[ws6]

iTrader: (13)

I would say pinion depth is set wrong. SOMETIMES the whine will go away after the gears have worn down some. I wouldn't bet on it though.

LT_WON

yeah from what the mechanic said they where measured correctly as far as backlash and pinion depth. I have read that there is a "break in period" is this true. I only drove it home, about three miles from the shop. Should i change fluid after a certain amount of miles ?

Ethan[ws6]

iTrader: (13)

The break in period consists of the first heat cycle, maybe two. But of course your mechanic is going to tell you everything was in spec. He isn't going to bash his own work haha

LT_WON

Isn't that the truth lol. I was expecting a little whine with this mod and its not unbearable just a different ride i guess.

Big Al

iTrader: (1)

Most of the time the whine will only get worse. Take it back to the guy that installed it and make them check it.

Al 95 Z28

dlandsvZ28

Do you still have the 3.23 gears and is there any wear? If not I might be interested, as I am switching from 3.73 gears back to 3.23.

FWIW after I switched from 3.23 to 3.73 mine whined a little bit too, at around 50 mph. Everything was replaced, bearings , races, the works. Of course the installer said everything was set to spec.

He blamed it on my Spohn floor mounted TA (torque arm). But - it didn't whine with the 3.23 gears and with the same Spohn floor mounted TA before the switch.

Do you have an aftermarket TA or still have the stock TA?

As for me - should I bite the bullet and buy new Motive 3.23 gears.

Note: the way I see it, the car when I bought it was stock and the rear end didn't whine. So you pay someone to change gears and then it whines - my Moser is the same way - sounds like the 52 chevy truck I used to drive when I was a kid. Absolutely annoying to drive.

STREETSLEEPER

iTrader: (6)

Whine on decel means the gear lash is to loose. Whine on the acel is when the lash is to tight. I believe that's thats the situation.

STREETSLEEPER

iTrader: (6)

I also heard that Yukon and American Axle Manufacturing are the gears to buy for quiet operation. A little more initially but worth the investment. Also some of those gears are noisy by design. Alot of those gears are made of very hard metal alloys and will make noise regardless. These magazine order gears are just that.

senicalj4579

iTrader: (41)

Mine are whining and just installed couple days ago (motive 3.73)

LT_WON

Yeah mine whine a bit with decelaration. When i take my foot off the gas they have a little howl in them. Harder material could be understood I guess. I am running the stock torque arm and I heard nothing from my stock 3.23 but then again those gears where 17 yrs old plenty of wear on them . gonna run them for a few more miles see what happens. It's always something....

whytryz28

iTrader: (28)

I installed summit 4.10 in my car and no whine, go tight on the lash and you'll be good.

01ssreda4

iTrader: (96)

I agree with this. However, I've built a ton of rear ends and some of them just have some noise. The same installer can then turn out a rear end that's dead silent. Its a tricky deal. I would not really make it an issue (with the installer) just get used to the noise. Did you install the blue or orange box Motives?

Big Al

iTrader: (1)

Same here. I wasted a lot of time on a 10 bolt I put 4.11's in, before I ever even moved it. No matter what I did the pattern would not come out right. I checked everything. So I knew up front it would be noisy and it didn't let me down It was in a V8 Pontiac Sunbird. When I had my shop I worked on lots of rear ends some guy put gears in that were noisy because of improper set up. I can count the one that I could fix without changing gears on one hand and have a few fingers left. If it's driven more than about 50 miles it's gone. Most were guys that just replaced the gears and used whatever shims were originally in there and expected it to work. And, sometimes it does.

Al 95 Z28

dlandsvZ28

Are you saying that you can ruin the gears in less than 50 miles if the pinion depth isn't set right?

I will have the rear end replaced at a shop where it has a lift where you can drive the car with it on the lift with suspension loaded. With that type of lift is it easier for the installer to get it right, or does it have to be on the ground and tested in order to hear whine?

When the installer installed my Moser, no one ever told me that we had to heat cycle the gears. It was on the dyno for a few runs, and then we drove it home from Indiana to Kansas.

Same for the installer who reinstalled my 3.42 gears in the Moser. They installed the gears and I drove it back home from Ok to Kansas without any heat cycling.

LT_WON

I believe the box was orange and black why do u ask> ?

Big Al

iTrader: (1)

No I said if the gearset is not set up correctly, pinion depth or ring gear placement. It depends on how far it's off. Most guys put a different gear in the car then go out and run the crap out of it to see what a difference it made. If the contact area is small it will gall the gears and quick. If you look through this section you'll notice this problem comes up about every day. 90% of what I see on gear problems are directly caused by a bad set up. It's not as easy as a lot of people think. The normal person has no idea that you shouldn't reuse the crush sleeve or even the pinion nut. You can't hammer in the side shims and so on. Then there is the fact that the pinion shim is under the rear bearing and to make a change everything has to come apart. Everything, the carrier has to come out, pinion has to come out and so on.

The 9" Ford is about the easiest rear to set up. A real Dana about the hardest. Why does that matter? Because most will just say it's close enough, because it's a lot of work to change it. With a Ford you can change pinion depth without much work, same for side to side ring gear adjustments and carrier preload. So you'er more likely to do it.

Al 95 Z28 w/S60

dlandsvZ28

I just ordered Motive ring pinion and they told me the Orange and Black box is a better gear and it is more expensive than the blue box.

Whether that is accurate ???? Sometimes sales will tell you anything even though one part number might not be any better than the cheaper part number.