If you're like a lot of other people out there, you've probably wondered at some point in time whether or not you're capable of installing rear gears in your Mustang. Well, there's no clear-cut answer to that. You will need above-average mechanical capabilities along with some specialized tools. All I can do here is show you how I go about the process and the tools that I use to get the job done.
You'll want to have on hand a bearing and seal driver set-- this will help you squarely and safely install pretty much any bearing or sealed that you come across-- a two-jaw puller to help remove not only the pinion flange but a couple of the bearings as well. You'll need a beam-type inch-pound torque wrench to check the rotational resistance of the pinion bearing once you've tightened down the pinion nut and crushed the new crush sleeve, a couple of large, high quality drifts to drive out old bearing races, a mag base and dial indicator to check your backlash, a pinion flange holding tool. This will help you keep the pinion flange from rotating whenever you're removing the nut and tightening up the new nut and crushing the sleeve. You can buy a tool that's specifically made for this purpose, or you can make your own. Either way, you're going to want to make sure that it can accept a 1/2-inch drive breakover bar.
And a couple of things I hope you don't need are a pinion depth checking tool and a caliber, be it digital or dial. If you're going to be replacing your axle bearings and seals, you'll want to swing by your local parts store and go ahead and rent you a slide hammer and an axle bearing attachment. Finally, a hydraulic press is going to make your life a whole lot easier, along with a good set of press plates and a bearing separator.
Along with the specialty tools, you're going to want to make sure and have a nice collection of common hand tools along with the stack of new parts, most namely a new set of Ford racing gears for your 8.8, along with an install kit and some axle bearings and seals, if you want to make sure that those are replaced, some quality gear oil and some friction modifier. A couple of things you may want to think about is a reusable cover gasket and, if your Mustang has some miles on it, one of these seal savers. That way you don't end up with a leaky pinion seal. From our website, latemodelrestoration.com, you can download and print the Ford racing instructions for this gear install. That gives you step by step written instructions along with all of your measurements and torque specs for the install.
Lift and support your Mustang and remove the rear wheels. If equipped with drum brakes, remove the drums. If equipped with disc brakes, take loose the caliper, remove the pads, caliper brackets, and rotors. Then remove the ABS sensors.
Remove the 10 differential cover bolts, drain the oil, and remove the cover. Remove the carrier cross pin bolt and then the cross pin. Doing one at a time, push in an axle and remove the C-clip. Slide the axle out of the housing.
Noting the orientation of the main bearing caps, mark each cap if it will help you. Remove the two bolts per side and set the caps, keeping them in order, be it right-hand or left-hand. Carefully pull out the differential and keep the shims located in the right-hand or left-hand position.
Mark your drive shaft and pinion flange. Remove the drive shaft bolts. Then remove the drive shaft or tie it up out of the way.
Using the flange holder tool, remove the pinion nut. Use a two-jaw puller to free the flange from the pinion. Remove the pinion from the housing.
Pry out the old pinion seal as well as the outer pinion bearing and oil slinger. Using a hammer and a drift, remove the inner and outer pinion bearing races. Take an opportunity to remove any remaining oil from the rear axle housing. Using a hammer and the race driver, install the new inner and outer pinion bearing races.
This is a great opportunity to replace your axle bearings and seals. Using a slide hammer and axle bearing attachment, remove the old bearings and seals. You can rent these tools at your local parts store. Using a bearing and seal driver, install the new axle bearings fully seated in the housing, followed by the seals. But the seals just need to be flush with the housing, not fully seated.
Clean off the new pinion bearing races with Brakleen and wipe them down with fresh gear oil. Take your new outer pinion bearing, and coat it thoroughly with fresh gear oil. Then slide it into place, followed by the oil slinger. And finally, tap the new pinion seal into place.
Using a bearing separator and the hydraulic press, remove the old inner pinion bearing from the old pinion and remove the pinion shim. Clean it up, and slide it on to the new pinion. Again using the hydraulic press, install the new inner pinion bearing onto the pinion. Thoroughly coat the inner bearing with fresh gear oil. Slide one of the new crush sleeves onto the pinion, and slide the pinion in to the axle housing.
Inspect your pinion flange. If a groove is present on the seal surface, either replace the flange or use one of the seal saver sleeves to repair your old flange. Slide the flange onto the pinion, and install the new pinion nut. An impact will only get you so far. Some good, old-fashioned muscle is needed to crush the new crush sleeve.
The combination of the flange holding tool and a couple of 1/2-inch breaker bars get the job done for me. Check the tension of the pinion flange often as you're tightening as you don't want to over-tighten. Using a beam-type inch-pound torque wrench, you're trying to achieve 8 to 14 pounds per inch rotational resistance with used bearings or 16 to 28 pounds per inch of rotational resistance with brand new bearings. As with a lot of things, you simply find what works for you and stick with it.
I take a cut-off wheel and remove the cage and rollers from the carrier bearings. Then I use a combination of a block off plate and a two-jaw puller to remove the remainder of the carrier bearings. Remove the ten ring gear bolts, and either tap or press off the older ring gear.
Use the hydraulic press to install the new carrier bearings. Slide the new ring gear onto the carrier, and start a couple of new ring gear bolts to pull it on slightly. Loosely install the rest of the bolts. And snug them up in pattern, and torque them in two stages, first to 35 pound feet and then, final torque, to 97 to 102 pound feet.
Thoroughly coat the new carrier bearings with fresh gear oil. Grab the new races. Clean with Brakleen, and coat with gear oil. Position them on the carrier bearings along with the old carrier shims in the same orientation they came out, and reinstall the two bearing caps. Tighten and torque the cap bolts to 90 to 100 pound feet.
Using a mag base and a dial indicator, check your, backlash. You are shooting for 0.008 to 0.012. Finally, check the tooth pattern with the supplied marking compound. Use the illustrations of acceptable patterns in the FRPP instructions to make sure your gear set installation passes.
Finally, slide your axles back into place. Clean the cover and the housing. And reinstall the cover using one of our optional reusable cover gaskets. Fill the axle housing with new oil and friction modifier, and completely finish resembling the car.
At this point, you'll want to correct your speedometer by using a new speedo gear, a speed calibrator adjuster, or programmer tuner, depending on your year model. Once the car is back on the ground and the wheels are torque, take a test drive. And drive responsibly for a couple of hundred miles, so the gears can set a wear pattern. And that concludes a successful rear gear installation that required no adjustments.
If you're replacing factory-installed gears with Ford racing gears, you should end up just as lucky. However, there are exceptions to every rule. That's where some of these other specialty tools will come into play, like the pinion depth checking tool. It comes with its own set of instructions on how to use it to get the correct measurement to select the right pinion shim.
If your marking compound shows a pattern that indicates the pinion is too close to the carrier or too far away, you'll want to pull this out, along with your caliper, measure out, select your new pinion shim, and start by rechecking your backlash. If your backlash is out of whack-- let's say it's too tight-- then that means, when you're looking at the back of the rear end, you're going to want to move the carrier from the right to the left to give yourself a little bit larger backlash reading. If it's too lose, than it needs to move from the left to the right to tighten it up. You want to take your caliper and measure your existing carrier shims and then use the selected shims provided in the install kit to transfer some of your shim thickness from one side to the other. A quick look at the Ford racing instructions will show you how much of a thickness change will impact your backlash readings.
Also, common sense comes into play as you'll want to make sure and clean everything thoroughly throughout the process and definitely make sure it's all clean before you go back together. That way you don't have to worry about any problems down the road. I also like to keep around some old bearing casings and races for installing the new bearings. This will help you make your installation of a little bit smoother and a little bit quicker.
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