Mustang Rearend

Hey, welcome to the horsepower shop.

We're always in the hunt for more horsepower and the engines of our cars. But this time we're gonna turn our attention to the rear end and show you how to make those horses work harder.

Now, project nightmare here has already enjoyed some power and suspension upgrades, but this time it gets a gear swamp that translates into quicker times on the strip.

Unless you're asleep in physics class, you probably already know that a lower gear ratio is gonna give you an improved mechanical advantage and allow that motor to spin up quicker. Now, it's also gonna allow you to take off from the stop light a little bit easier with less stress on the clutch and the drive shaft

on the downside though. Well, it's probably not gonna help out your fuel economy and you're definitely lose some top end speed and more importantly, well, you're gonna wear out some engine parts a little bit quicker because you're turning the engine more revs per mile. Now, the gear set that we're using is a pro street set up from us. Gear. It's got 11 teeth on the pin here and 41 teeth on the ring gear. Now that's gonna give us a 373 ratio.

Joe's Mustang came from the factory with a three 27 gear set. It didn't, well, that's about a 15% increase in mechanical advantage.

We're gonna bolt that ring gear to this new Ed differential from Auburn gear. Now, Ed

stands for electronically controlled traction enhancing differential.

And the cool thing about this differential is you can control its activation from limited slip to a full locker. And the flip of a switch.

When you go around the corner, the limited slip allows the outside wheel to travel faster than the inside wheel.

But when you're in the locker mode,

like at the drag strip, it lets you put all the power down.

Yeah, this is such a new piece of hardware that I thought I'd bring a cut away in to help you understand how it works. When you flip that switch, that Mike told you about earlier, this electric coil creates a magnetic field

that pulls this cone into contact with the differential housing. Now what happens then is the cone slows down and causes these balls to ride up in the grooves and actually lock up the side gears.

The side gears are spline to the axle. And of course, that's how power gets to the wheel.

The other side of the differential uses a standard limited slip clutch pack. And of course, the ultimate result is

equal power to both sides.

Right now it's time to get to work. And of course, that means getting the rear end out from under the car. So once it's in the air, we can disconnect the drive shaft, the control arms and well, anything that's attached to that rear end,

the first thing we do is loosen the rear cover

and drain the fluid.

Now, we can remove the shaft, retaining bolt

and the pinion shaft

then slide the axles toward the center

and pull the sea cliffs.

And with those out of the way, we're ready to slide the axles out.

All right. Now, before we do anything else though, we need to check the backlash on the ring and pinion. And that's actually the play between these two gears here

to do that. You're gonna need a magnetic based dial indicator like this one and it just mounts right here on the rear end housing,

then hold the pinning gear steady while you turn the ring gear one direction

until it stops.

Then you can zero out

the dial indicator.

Now rotate the ring gear the other direction and check the reading.

That's your backlash.

And just to be sure, check it in a couple other areas around the ring gear.

Then after marking them for their location, go ahead and remove the caps,

the ring gear and differential come out as an assembly.

Then you can remove the pinion gear

with the housing strip. Now is a good time. To give it a thorough inspection and clean all the mating services with some brake cleaner.

I haven't noticed any noises coming out of this rear end. But if you check here, looks like this wheel seal's been leaking. So we'll replace all the seals and bearings with some new ones.

So we don't have any problems down the road

before we install the new pin. We need to slide on this shim and a new bearing. Now, we're lucky enough to have a press in our shop. But if you don't, any one of your local machine shops can take care of this for you.

Next drop the supplied crush collar onto the pinion gear and slide it into the housing,

then reinstall the pin yoke

securing it with the new nut from the kit.

Now, before you do that, put some lock tight on the threads, that way the nut can't back off once the preload is set.

Now us gear recommends 25 inch pounds rotating torque for new bearings and 15 inch pounds for old ones.

Well, I've been busy trying to get this differential ready to install. I've already pressed new bearings on and here's something that you really need to pay attention to

each one of these mounting holes for the ring gear has little burrs on it that need to be knocked down.

So the ring gear will fit flat against this flange here. Now, what I like to use is a flat file on both the differential and the backside of the ring gear to make it nice and flat.

Well, now here's a little tip for you. It'll make it a lot easier for you to get this ring gear in place.

Use a heat gun or submerge the ringer in boiling water to make it expand

with dreadlock on the new ring gear bolts to

them down to 70 ft pounds in a crisscross pattern.

Well, now we can drop our new differential into the housing

so we can establish our Shima

baseline.

There we go. Now how do we do that? Well, we're gonna show you how right after the break.

So stay with us,

man. I can't wait to see the difference in this thing.

Well, we're back to finish up the upgrade in my 96 Mustang and with the new Auburn differential installed in the housing.

Well, I guess it's time to show you how we established that shim pack baseline. Chuck mentioned,

put together a shim pack from the installation kit

and after you see the bearings by turning the case a few times

drop in the shims to establish a slip fit between the housing and differential.

A slip fit is when you put together the thickest amount of shims that can be installed by hand with only a slight resistance.

Once you've got that

remove the differential

mic, the combined thickness of those shims divide that in half and well, that's your baseline

with half the shims on each side of the differential,

rub it back in the housing

with the main caps installed. Tighten them down as you turn the pinion gear back and forth.

After this, we can torque them down to 80 ft pounds,

then check the backlash

and compare it to the original reading.

That original reading by the way was 11,000. So this time we got about six. So we need to increase the backlash by removing shims from the ringer

side and adding them over here

if we had to reduce our backlash. Well, we do just the opposite. Well, here's a little tip for you. 1/1000 Shem equals about 1000 backlash

in case you're wondering, we ended up taking about five thousands worth of shims off the ring gear side and transferring them over here to this side.

And then we had to set the preload on our differential bearings. Now, the way that we did that was by adding another four thousands worth of shims on each side.

Well, I've just finished re twing the main cap. So now we can install our mag base indicator again

so we can recheck our numbers. Now, this is a step that you're probably gonna have to do several times to get it right. And hey, if you don't take the time to get it right. Trust me, your rear end is gonna howl like a pack of wild wolves.

We're using 31 spine axles compared to the stock 28 for more contact area and added strength.

Now, we got our direct replacement axles from superior.

Their splinting process gives us 35% more strength than the stalkers. And I've already pressed in the wheel studs, N A BS ring

before sliding them in all the way,

you have to remove the pinning shaft, lock bolt and the shaft itself.

Now push the axle all the way in,

slip, the sea clip in place

and pull the axle back out

with both axles in place. Install the pin shaft and torque it to 20 ft pounds.

This new cast aluminum cover we got from T A performance is gonna give us extra strength. Thanks in part to these adjustable stops that help control deflection of the main caps. Now, the hole I just drilled is to run our wiring that controls the differential or after I install this stress relief hardware.

But before we bolt the rear end back up in the mustang, we're gonna top it off with some gear up. Obviously, it's a lot easier this way.

Looking good.

All right.

Let me line it up.

There we go.

Ok.

Now, all I have to do is find a place to mount the activation switch and the other necked is a simple three wire hook up.

Yeah, but you're not ready to go out and set low, et just yet. In fact, you've still gotta break in that gear set properly. And what us gear recommends is running. The car

jack stands for two or three minutes in both forward and reverse.

Then you can take it out on the highway and run it up and down through the gear several times, then take it home and let it sit in the driveway and cool.

Well, speaking of that, there's a lot of cool stuff still to come on horsepower. So, stick with us.

Hey, you know, a few weeks ago we launched a search for a real ride challenge car that we were gonna use as one of our special horsepower build ups.

Well, the selection committee looked through literally thousands of cars before they chose just one

and this is it.

It's a 19

69 olds cutlass convertible.

Yeah, it's hard to believe we've never worked on an Os in the shop before, but that's about to change. And well, for good reason,

this car's got a strong muscle car legacy, especially with that performance flagship 442

for 10 years. Beginning in 1964. The numbers 442 symbolized mid size muscle car performance.

Literally the numbers meant four barrel carburetor, four on the floor and dual exhaust over the years the specs changed, but the name stuck and the performance just got better and better, especially in 1968 when

HST jam, the 455 cubic inch big block in this awesome a body.

The hurst

S

was king of the 442 Cutlasses, but is

with a 442 badge on the side and a 455 under the hood was destined to become part of a horsepower legend

one that turns heads and captures the hearts of America's muscle car lovers.

Of course, most of the real 440 twos have been coveted by collectors, but thank goodness, they've also been imitated by enthusiasts who like the look without the price tag. And, well, that brings us to the owners of this Red Rocket,

Ernest and Amy Smith from Central Florida. Welcome to the shop.

What do you think about taking part in this uh real ride makeover? Oh, it's great. Yeah, I'm real excited. I'm hoarse because I was telling everybody I know about it. You sound like you've been screaming about. I

have a little bit.

The body of this olds is in pretty good shape for its age.

But things like trim pieces, weather stripping

and carpet do need replacing. Man. Looks are one thing, but I want to see what's under the hood. Now, I was listing this thing when it got pulled in the shop and I think this is one rocket that lost its after burner a long time ago. What do you got here, Ernest? Well, it's a stock very tired. 350. Uh,

and what would you like to see under there?

Uh 455 would be nice.

Yeah,

I agree. There's no replacement for displacement. But

if we do that, the rest of the drive train will probably need a little bit of help too.

You're not arguing. Not a bit. Tell me something. Have you ever had this thing strapped to a dyno Jet? Never.

You say we do that? This ought to be fun.

Well, I got good news and bad news. The good news is the cutlass survived. The

dyno run. The bad news is I only made about 100 and 59 horsepower.

It's not really a muscle car, is it? I gotta tell you our budget, Honda beat that by about 40. I know that makes you feel good.

But I tell you what, when you and Amy come back in a few weeks, I think you're gonna be pleasantly surprised. We look forward to it. All right, have a safe trip. Thank you, sir.

And of course, now you'll get to see it all happen beginning in a couple of weeks. So stay with us. We'll be right back.

Horsepower T V's Quick Tech is brought to you by

Wyotech.

Today. We're going back to school literally for some

bows, spring basics. All thanks to lou

wreck at wild

Texas, Blairsville, Pennsylvania Campus.

So, what do you got here?

Well, Joe, what we've got is a good chronological order of out spring tech ranging from approximately the fifties to today.

The first spring we've got is a

single wound spring, no dampener. There's no provisions to control spring oscillation, high RPM

spring doesn't offer a good

resistance to

uh resonating at its own frequency

as RPM increases

the next style spring

we would use would be a

single long spring with a flat, long dampener inside.

The dampener allows the spring to rub it to a higher RPM

in the engine without the spring oscillating

causing the valve to float. He been around a while too and they work pretty well.

They sure do. We see these from many OEM applications,

um, still today.

Now, an old spin off from the seventies design is the Beehive Spring.

This is a spring comp cam that is currently introducing into the high performance market.

The Beehive Spring, as you notice, it's shaped like a beehive, it's tapered toward the top.

The advantages are,

if you look the first couple of coils in a be high spring will actually compress for the rest of the spring well,

along the spring to be effectively shorter and has its rate go up progressively

as the lift increases.

And that's pretty interesting. But you know, everybody wants to make more power these days. Let's say you got some of these LT one heads on your, uh Camaro.

You want a more aggressive cam shaft. Well, that's gonna affect the B

springs too. That's right. So it will, it sure will. If you look at these stock heads, they got a fairly narrow diameter spring, you want a better cam. You gotta get a better spring just after market head here, it's got a much larger diameter of spring.

Ok.

In Concordance, it needs a larger diameter retainer

that retainer might present some issues of clearance. You look at this rocker arm right here.

Spin di ground away.

You wouldn't wanna do that. No, I sure wouldn't. That's gonna compromise the strength of the rocker a

couple ways around it are, you can run a better rocker arm, which is expensive

and even more expensive shaft rocker system. Yes.

Lastly you can run a Beehive spring pop

cams.

It's a really good design

and it replaces the old design,

same width,

same height

and just at the top

one is much more small,

very interesting. So new technology it's more cost effective and it's gonna help you get more power and you get all the advantages of this later model technology. Spring.

I like it.

Yeah.

Hey, I just got through recalibrating the Mustang's computer for the gear swap we made today.

All thanks to the super chips micro tuner. Well, now you guys with late model Camaros and Corvettes can get one for your LS one or LS six. You can free up some horsepower, raise your speed limiter or rev limiter, even change the shift points and firmness in your automatic and get this with

this thing. You can read and erase diagnostic trouble codes in your ECM to get one, just go to the ATM and pull out about 460 bucks.

Three deuces can be a winning hand at poker, but three deuces on your small block, Chevy can attract a lot of attention and make great Power. Barry Grant's six shooter is an updated version of a classic car

set up with a look all its own that it comes with progressive linkage

and an air cleaner that complements the clean design.

It's a design, by the way that works well on street machines, street rides and even trucks, the price just under 2400 bucks. Well, if you like things that are cool and classic, just wait, you see what we have in store next week, you're on horse power.