9" gear install help

[JSlack]

Does anyone have any step by step instructions for replacing gears in a 9"?

I have a 9" with a detroit locker and 3.50's. I have some 4.10's that i would like to put it. I have a dial indicator and mag base.

any help would be much appreciated!

thanks,
JSlack

[Old Bird]

You really shouldn't need the dial indicator as long as you don't get any of the shims mixed up. Everything is already set on it, it's just a matter of getting the locker out, replacing the gears, and getting it back in. Ok, maybe not quite that simple, but there's no worries about needing to reset spacing or anything as long as you don't mix up, move or lose any shims.

[JSlack]

I won't need to reset the mesh between the pinion and ring? don't need to look for that optimal pattern in the grease?

[Old Bird]

I won't need to reset the mesh between the pinion and ring? don't need to look for that optimal pattern in the grease?

Unless the ring is thicker than the one you are replacing, it won't change the position of the carrier, it will still be set from before. The shims are what set that, and you'll be reuising the same ones.

[JSlack]

I think i understand. I may just have to tear into it and go from there...haha.

not sure if the thickness of the gears is going to be the same.

I put all new bearings in maybe 2000 miles ago along with the axles, should the bearings be replaced while im in there? it is only going to see a little street time and mostly track time.

what else will i need to complete the install? and what fluid do you guys recommend...remember it will be making passes down the strip...not up the mountain...haha. I like quality too...

[JSlack]

http://www.fordification.com/forum/view ... 87#p382987

[averagef250]

I won't need to reset the mesh between the pinion and ring? don't need to look for that optimal pattern in the grease?

Unless the ring is thicker than the one you are replacing, it won't change the position of the carrier, it will still be set from before. The shims are what set that, and you'll be reuising the same ones.

That's not quite how it works. Shims are a function of the gears and housing. Yes you need to know how to read the gear pattern and set the correct backlash/preloads.

You cannot just slap different gears in and expect the old shims to be right. Odds are they'll be close, but not right. They're a starting point and that's it.

[JSlack]

You cannot just slap different gears in and expect the old shims to be right. Odds are they'll be close, but not right. They're a starting point and that's it.

this is what i thought...and why i was looking for a step by step type of deal, especially on how to read the gear pattern, and what to do to get it to that "sweet spot".

[Old Bird]

That's not quite how it works. Shims are a function of the gears and housing. Yes you need to know how to read the gear pattern and set the correct backlash/preloads.

You cannot just slap different gears in and expect the old shims to be right. Odds are they'll be close, but not right. They're a starting point and that's it.

It's always worth checking. But I've done front and rear gear changes in Dana 44s, Dana 60s and AMC 20s. Plenty. And only when there was an obvious difference in ring gear thickness did it need any change.

[JSlack]

The major difference here though, is that the 9" is all set in the 3rd member, where as the 60 and 44 are all set in the housing, different steps to set them up.

[averagef250]

Differentials are all the same. pinion preload, pinion depth, carrier preload and backlash all should be dealt with.

I won't argue with the idea that you can slap gears and run them, things don't have to be perfect to go down the road, but there is a difference in wear, noise and failure between slapping them in and doing it right.

[JSlack]

I need to do them right, will be seeing a majority of track time

[F100builder]

If I'm not too late, try this... http://www.badshoeproductions.com/index.html

I bought this DVD and it helped me rebuild my 9" in my '56. This guy is a Ford Senior Master Technician with over 35 years of experience and he tells you what to look for as far as problem areas and gets into both standard diffs and LSD's. Great video!

[Alvin in AZ]

If the "Bad Shoe guy" does it for you that's cool. :)
Me? He really gets on my nerves bad. :/
Don't know why, he just does. :/

Here's what separates the guys that know how from those that don't...
http://www.youtube.com/watch?v=g-RyFBZWSYM
http://www.youtube.com/watch?v=C8bLFqSdgYI
http://www.youtube.com/watch?v=8PgMVP596mw
http://www.youtube.com/watch?v=x5_0FYWgWI8

You can measure your ass off and still not get it right! :/ BTDT :)
Being shown what those videos show is the where the "real how-to" is at.

Once you get into it, it's obvious as anything how to set the backlash and
pinion depth.

I agree with "old bird droppings;)" check the +/- numbers on the original
and the new one and make the change in the shims as needed if they are
both the same then make no change. :) Make whatever change the +/-
numbers say to change it. It "should" be right on the money.

I also agree with Dustin (average) in that it might not work for you but it
did for me right up until the guys at Richmond Gear got involved. :( Every
guy I talked to there told me to do something totally different, opposites
even. :/ They didn't know squat because it wasn't in their hands, see? :/

Everybody seems to be an expert! :/

You got the sucker in your hands, you work on it 'til you think it's right then
take it to a differential shop and have them double check it ->before<- you
put a single mile on it. Ok? ;) That's the cool thing about a Ford9inch. :)

Alvin in AZ
http://www.panix.com/~alvinj/file12/Ford9inch.jpg (homemade tool)
http://www.panix.com/~alvinj/file12/Ford9inch-B.jpg (back)(normalized file)
http://www.panix.com/~alvinj/file12/Ford9inch-S.jpg (side)
http://www.panix.com/~alvinj/file12/yoketool.jpg (bed frame;)

[Alvin in AZ]

http://www.youtube.com/watch?v=7MWsPJBC ... re=related
;)

Alvin in AZ