silverTA2002

iTrader: (1)

Well, I finally installed the 9" I've had sitting in the garage for months. 4.11 Motive gear, 31 spline moser axles, standard case, rebuilt ford trak loc posi, new bearings. I'm using 75 90 fluid with a tube of Posi additive. I've been pretty easy on it so far for 50 miles.

My questions are:

1. There's a slight whine on accel and decel, will this get quieter with time?

2. The car vibrates a bit (driveshaft) I flipped it 180 degrees and it got better, but is still slightly noticeable at hwy speeds, how can I fix this?

3. The Posi unit moans when going around corners. I even jacked up one wheel, with the other on the ground, and turned that wheel and it would make a low moaning sound. Is this part of the break in? Will the noise go away?

Scott@DrivelineSolutions

iTrader: (22)

After break in perform an oil change and put in Ford additive right from a dealer. I assemble a lot of Motive Performance gears and to date we have never had a single one come back. But be aware there are Motive gears that are their basic line and imported from Indonesia. We tend to stay away from those and run the Performance line. You will need to get your driveshaft balanced since you went with the 4.11 ratio. The factory did not high speed balance these and gear swaps draw vibrations.

silverTA2002

iTrader: (1)

The Motive gears I purchased were not the standard blue box ones.

So, what about the posi moaning and groaning around corners?

It's worse when I'm in gear and giving it any power at all around corners.

Scott@DrivelineSolutions

iTrader: (22)

The gear maybe set wrong, do you happen to know the pinion shim used and what case and support is in there?

The posi clutches may have too much wear on them and someone just shimmed it really tight. Who built the center section?

Vintage Iron55

Hmm, I have not heard groaning from stock Ford posis before. The probem I see most often is that they burn up after one night at the drags, due to the low preload from the factory. I have replaced the cluthes and shimmed them very tight on purpose for people to eliminate this problem with great success with mild automatic cars. Hard leaving stick cars will usually then break the "hat" right off at the bolts where the factory case is weak. I would try the additive mentioned above. That may quiet down the groan. Best of luck. I sure prefer my true track.

Those 4.11s dont usually take that much shim in my experience. I like mine to touch closer to the inside on the drive side and about dead center on coast with about .006 to .008 on lash. How about you, Scott?

Scott@DrivelineSolutions

iTrader: (22)

Average pinion shim has been .018-.022 on Motive Performance gears with .007-.008 backlash the norm. I actually get the pattern dead center and then pull out .001-.002 pinion shim to keep them quiet.

silverTA2002

iTrader: (1)

I'm not sure about the pinion shim.

The posi clutches are brand new. We put them in pretty tight. It doesn't want to slip much while turning 90 degrees right with any throttle.

My mechanic friend built the center section at his shop. I watched while he did it.

I think it may be a fluid problem. I used regular 75 90 fluid. But, when I read the back of the bottle it said, "Ok for top off only on posi or limited slip" But, I figured it would be ok with the posi additive.

silverTA2002

iTrader: (1)

As far as the wear pattern on the gears go, it was basically right dead smack in the center when he set it up. It looked exactly how the directions pictured it.

silverTA2002

iTrader: (1)

Oh yeah, and backlash was set at .009

I do remember him only using like one shim on the pinion.

silverTA2002

iTrader: (1)

I used this stuff: Coastal Gear Oil 75w-90



From autozone.

silverTA2002

iTrader: (1)

UPDATE:

1. I switched to Lucas 140 weight, and the whine was cut in about 1/2.

2. The vibration was a combination of a bad yoke, and the wrong pinion angle. My pinion angle was slightly positive, now I switched it to slightly negative. There's still a slight vibration at 60mph, but it's not too bad. Eventually, I'm going to put it on a lift and get the pinion angle exact.

3. I used the Ford limited slip additive, all the moaning and groaning went away, and it's as smooth as stock around corners, no binding either.

oange ss

iTrader: (50)

back from the dead......which yoke was bad ? what was bad with it ?