[96lt4c4]

I sent another email asking to swap them for a 3.70, this was the reply I got.


I don’t stock any 9” gears , our site is supposed to be linked to Yukon’s inventory .
So , unfortunately there are no 370’s availably ( even if they would consider a swap )
Which he didn’t mention or offer.

[big gear head]

Who did you send that email to?

[96lt4c4]

Originally Posted by big gear head

Who did you send that email to?

I bought the gears from EMS offroad. I spoke with them about the problem and sent them an email with pictures of the pattern. They forwarded it with the pictures of the pattern to thier Yukon rep. This was the reply from the rep.

[96lt4c4]

Well now I have a Motive Performance 3.70 gear in there. I stuck it together last night before I went in the house. I guessed and put in a .021 shim, set lash to .008 and this is the pattern I got. Looks pretty good to me the coast is kind of high on the tooth but drive looks good. This is the first gear that I have put in this thing that both coast and drive are fairly close to center heal, toe, face and flank. Of course I am going to play with it some more, but what do you think? The gear doesnt feel as smooth turning the ring gear by hand as the other gears but the pattern looks better.

[302 Z28]

I have posted this information before, but it's been a while. It is some very good general info on setting up ring and pinions.

This link is specific to Ford 8" and 9" installations.

Hope it's of some use.

Vince

[302 Z28]

Originally Posted by 96lt4c4

Well now I have a Motive Performance 3.70 gear in there. I stuck it together last night before I went in the house. I guessed and put in a .021 shim, set lash to .008 and this is the pattern I got. Looks pretty good to me the coast is kind of high on the tooth but drive looks good. This is the first gear that I have put in this thing that both coast and drive are fairly close to center heal, toe, face and flank. Of course I am going to play with it some more, but what do you think? The gear doesnt feel as smooth turning the ring gear by hand as the other gears but the pattern looks better.

Are you pre-loading the pinion as you turn the ring gear? I usually use an old fan belt and it usually takes two people. One to hold the fan belt over the pinion flange and pull down and another to rotate the ring gear. I use a wrench on a ring gear bolt to rotate the ring gear back and forth as the pressure on the pinion flange is applied. This usually gives better pattern definition.

Vince

[96lt4c4]

Originally Posted by 302 Z28

Are you pre-loading the pinion as you turn the ring gear? I usually use an old fan belt and it usually takes two people. One to hold the fan belt over the pinion flange and pull down and another to rotate the ring gear. I use a wrench on a ring gear bolt to rotate the ring gear back and forth as the pressure on the pinion flange is applied. This usually gives better pattern definition.

Vince

I load it by hand, I cant get a wrench on the ring gear bolts becasue the posi unit is in the way as well as the extra large aluminum caps. I can get a socket on but can only turn it very little before it hits the caps. I am getting ready to take a look at your links.

I did some research over the weekend and I am begignning to think maybe my carrier preload and pinion preload may not be tight enough. Even though these bearings may only have 100-200 miles on them should I still set them as tight as new bearings? I have an old axel with the splines cut off and a nut welded to the spline end of the axel about a 5 inch long tool. I stick it in the carrier and use an inch pound tourqe wrench to measure carrier preload. I have about 15 inch pounds on it. Also the cap bolts, in the Yukon manual it say 60 ft/lbs, the Motive manual says 80-85 ft/lbs. Which is it? They are 1/2 bolts with 3/4 heads.

[302 Z28]

80-85 ft lbs.

Vince

[96lt4c4]

Originally Posted by 302 Z28

80-85 ft lbs.

Vince

What about carrier bearing preload. Do you know of an inch pound reading or? I have also read that the case needs to be spread apart .010. My case is aluminum though.

[302 Z28]

I have never spread the case on a 9" Ford unit, only Spicer types like GM and Chrysler used. You set carrier bearing preload and backlash with the large adjustment rings.

Vince

[96lt4c4]

My father in law just remebered that he had the factory Ford service manual for his old 1975 Ford pickup. Guess what it has in it, the original Ford procedure to setup a Ford 9 inch, I am going to take a look at it tonight.

[302 Z28]

I just discovered that Motive gear sets are made in Italy, should be a decent gear set. Those dago's know how to machine

Vince

[AutoGear]

I can vouch for most Italian gear cutters. Our stuff was made by Antonio Masiero; who was bought out by Euroricambi SPA. Other italian gear vendors of note would be SMI who sed to make OEM replacement quality stuff

Note: their material selection won't be the same as what we're used to in the states. We spec ASTM 8620 and they use a steel close but not exact to 8620. Im not sure if its something to do with the rating/classifying system or not.

[96lt4c4]

Straight from the Ford manual. Back lash setup instructions, and patterns.

[TimoFinn]

have you driven it yet?still noisy?