Just finished gears!! OMG!!!!

Yeah, my car was really slow before. I can't even describe the feeling I get now when I punch the car. I am planted into my seat!!!!!!

I had access to a lift, so the install only took 4 hours. Thanks everyone for their help/info. Couldn't have done it without you.

But there are a few things I wanted to point out. I hope this will help anyone who decides to do them yourselves.

First, definately soak your ABS sensors in PB blaster or equivalent the night before you install the gears. Since I did, mine came out like butter. Absolutely no problems.

My Differentail Shaft Locking Bolt required a 8mm socket to remove it. For some reason, the 8mm wrench wouldn't work, and would strip the bolt. But it's east to get a socket on it anyway. Just wanted to note that because you can try every open-ended wrench you have, and none will fit. My 8mm wrench was somewhat new, so I can't imagine it being the problem.

When you remove the 4 driveshaft bolts from the pinion flange, "butt connect" two plastic cable ties together so they are 2x as long, and simply tie the DS to the metal bracket that is above, on the floor pan inbetween the two mufflers. It keeps it out of the way, and you don't need to remove the DS completely and worry about transmission fluid everywhere.

When you are ready to take off the main caps, clean off the caps surface. You will see arrows on the caps. Remember which way the point on each cap. Re-install the same way, or else you will have issues. Also, don't mix the left cap with the right cap. They need to be reinstalled on the same side they came off of. Also, you will see the carrier shims on each side, just to the outside of the carrier races. The shims aren't symmetrical; One side has a taper to it. Remember which way the taper points to before you remove.

After you remove the pinion nut, you will need to use a metal hammer to knock out the pinion flange. You can either whack away at the tail end of the pinion gear, or whack away at the back side of the pinion flange. Either way will work just fine. A rubber mallet is a complete waste of time.

Measure your new pinion head with the dial caliper before you even start the project. It is somewhat time consuming to be accurate, so might as well do it at home before the install. Also, sand the back of the ring gear at home too. Save you time.

The two pinion heads should be really close (new=1.879 & old=1.880, only off by .001). The shim that was used on the old pinion was .034, so I only had to add .001 to the total shim thickness (new shims were .017 + .018 =.035).

To remove the pinion bearing, you need a large bearing seperator. You can get it at Harbor Frieght for $10. You won't need a press. I used one, but it came off with extreme ease. You could take two thick bricks, and use them to support the bearing seperator, and just hammer on the tail end if the pinion gear.

When they say in the install articles that it take very little to get the bearing pre-load within spec, they are correct to the teeth. Once you tighten the pinion nut enough so the pinion has no play, it takes maybe 1/4 total turn to get it in the right spot. And it's extremely easy to go over. My first time I tightened it to 16 in/lbs which is too much for a used bearing (only by 2in/lbs), so I had to remove the pinion again, and start over. The second time, I was very careful, turned the breaker bar about 1 inch, measured, turned another inch, measured, etc until I got it right.

Something that confused me before, which I thought I might bring up. When they say "pre-load", what they mean is the amount of torque required to turn the pinion without something bracing the pinion. Basically, the amount of torque required to turn the pinion freely, or amount of drag if you will. So remember, the preload measurments are to be done with nothing bracing the differentail. Only when you are tightening the pinion nut do you brace the differential.

You don't need a 4 foot breaker bar to tighten the pinion nut. What you need is a little Newtons 2nd law (action-reaction). Install 2 of the driveshaft bolts part way. Then get a big pry bar (1-1/2ft long), and stick it inbetween the two bolts. This will be one lever arm. Then, you use the breaker bar (1-1/2ft long) w/ socket, push the pry bar one direction, and pull the breaker bar another. Doing this will keep you steady and not slide around all over the place. Also, this allows for much more controlled compression of the crush collar. We tightened the nut until we read 4in/lbs, then tightened until we read 6in/lbs, etc. Also, remove the pry bar when you are reading preload.

We tried to have one person hold the pry bar, and one turn the breaker bar, but we both would slide on the floor. The above way worked much easier.

We reinstalled the carrier into the differentail, and realized something. There truly only was 1 shim on each side. We couldn't have adjusted backlash if we wanted to. I didn't but and carrier shims because from the articles I read, they said you could remove shims from one side, and put into the other. This is not the case at all. I would have needed to buy carrier shims, measured how big the right side shim was, and used mulitple shims to replace the one big shim. And the same for the left side.

Turned out that the backlash was right within spec, .012, without any shim adjustments necessary. Gotta love FRPP gears. Hell, I could have even used the same pinion shims and gotten away with it.

Since the articles tell you next to nothing about setting up the dial indicator or specifically how to measure backlash, I will give you some info.

Backlash is the distance inbetween any ring gear tooth and a adjacent pinion gear tooth. You could call it the play between the gears also. The dial indicator should be setup so it is pointing straight down, perpendicular to a ring gear tooth. Spin the ring gear down, then put the tip of the dial indicator on one of the teeth. Then, wiggle the ring gear starting up, then down, then up, and down. You aren't trying to spin the ring gear persay, you are trying to see how much you can turn the ring gear without moving the pinion. If the pinion moves, you need to start over. You will get the hang of it. It's only a pain to get the dial indicator setup initially.

Don't forget friction modifier for the gear oil. Definately a must unless you want a one-wheel wonder car.

I think that's it for now. I will post/edit this later if I think of something. I will also add a picture of myself with a nice red mark on my forehead. A driveshafts falling on your head kinda hurts.

Here are some links to good write-ups. Each have their own unique information that are helpful.

This is good to read first to get a general idea of the install.

This has tons of pictures, and shows you how everything is assembled. Great read if you plan on replacing all of the bearings or do a complete rebuild.

This also has some good info. Slightly more descrpitive.

After reading all of this, you may think that this is out of your league. I only am writing this in such great detail because I have NEVER EVER worked on a differentail in my entire life. I had ZERO experience with measuring backlash, using a dial caliper, etc. I haven't even removed the brakes on the mustang. It just goes to show you what time, research, patience and will can accomplish. I think I read all the way through the 1st/2nd links about 4 times each. When you haven't worked with stuff like this before, it takes time. After the last time I read it, I had a firm understanding of what was involved & had no doubts in my mind that I could do this.

I had to learn a lot, I will say that. But I did have a saving grace, if you will. The person that got me access to a lift helped me with the install. He has removed axles, differentials, etc before, so he was a big help. But he had never done a gear swap; So the only thing he could have accomplished was take everything apart, and put it back together (basic rebuild). The hard stuff was left to me.

So if I had to do this on jackstands, with someone helping, but little experience in this particular field, then I can see it taking much longer.

I still think doing gears in under 4 hours was some kind of record for noobs like us.

I also attached a MS word document with the tool checklist that I made. It might help you guys.

Scott