Hey guys,

I just had my gears replaced in my 9" rear with Motive 3.50's and the mechanic swears the backlash was right on and same with the wear pattern, well we take it for a test drive and the gears are whining...

1 - Has anyone had troubles with Motive gears and can this be the fault of the manufacturer ?

2 - Assuming he did not have the gears set up correctly, have the gears been damaged now that we drove it (less than 1 mile) ? Can this be eliminated ?

He feels bad and will take it apart again to re-look at it but I'm concerned the problem may require another ring and pinion...?

Ideas ?

what gear oil is in the car now, I know with my richmonds they said not to use synthetic.

I installed 2 new Motive 3.42 gears in a 67 12 bolt and both whinned, not bad but just the same, they are not in now. The backlash and pattern were perfect on both. Talked to rear end guy in PA. that installs and sells Motive gears, he sets them up loose .010-.012 backlash. That did not work either. I put a used 3.31 GM gear in and all`s good. :D

Obviously GM gears are not going to be my solution...:)

As for gear oil, I doubt they used synthetic....

I know with my richmonds they said not to use synthetic.

Thats interesting .... I dont set up a lot of rears, but when I first started I called Richmond and they told me to use thier synthetic gear oil

http://www.richmondgear.com/01pdfs/OILVID.pdf

I have used it in every one I have set up and never had a problem. Why would they sell something then tell you not to use it ?

I see Freddie seems to like Motive gears. I'd love to go back to my shop with some supporting opinions that its the set up and not the gear. I can just see this ending up in a pi$$ing contest over who's fault this is with me being the loser....

Any gear manufacturer can get a bad batch of gears from time to time. I haven't had any problems with Motive Gear, but I haven't installed any of them for about 5 years. I've been using other brands lately. I have a Motive 3.73 in my old truck that has worked very well for about 9 years.

I installed a Yukon 3.73 in a Camaro a few weeks ago and all looked very well. When my customer took it for a drive he said that it was making noise. I thought he had forgot to put oil in it, but that wasn't the problem. I took it back apart and checked everything, even replaced some of the bearings. I checked the pattern again and it was still good, but it still makes a noise in about a 10 MPH range under light throttle. Some gears just make some noise. No matter how hard you try to get it right, sometimes it just doesn't work out.

As for your gear, I doubt that driving it 1 mile has caused any damage. Let him try again and see what happens.

Thanks Freddie, we'll see what happens monday !!

Well they re-did the pattern and put it all back together which improved the noise but still not there. I called Motive and they told me that a pinion depth tool MUST be used to set it - one was not used. I have dropped the carrier over at another shop for them to look at using the depth gauge.

Now another question, my pinion support is a Strange aluminum Daytona type. It was on the car - can that be causing set up issues ? i saw posts talking about these not being used on the street....???

This shouldn't be the problem. I don't recommend the aluminum Daytona for street use because I feel that the aluminum will expand and cause problems with the pinion depth. Drag racing doesn't put enough heat into it to cause problems, and even if it did it would only be for a short trip down the track. When you use them on the street they get a lot more heat in them and run for a longer time with this heat. I just think it could cause the pinion depth to change. I prefer the iron Daytona for street use.

Had another shop set up the diff and voila, no more noise. The other guy was pretty red faced....