Symptoms:
- Rear wheels don't want to turn going around tight low speed right or left
turns.
- Nasty clunking coming from transmission area.
- Car feels like it's being held back, may even die, when trying to backup and turn left or
right.
- Should be flakes of metal on the transmission drain plug.
- Likely to occur after a hard launch.
Rebuild or Replacement Choices:
Center Differential Rebuild Kit Mitsubishi part number MD733338 (Ref#22620 in image
below)> Conicelli Mitsubishi $140+S&H.
Ref# 21173V is the spacer that
comes in several different sizes. You will have to determine which one you need based on
the amount of end play in the differential after you install the new guts. Note:
Ref# 22619 does not come in the gear kit. The picture below represents the
complete contents of the gear kit.
Welded Center Differential (2 Welded Gears)> Buschur
Racing $300+S&H The input shaft is welded to the housing > the
spider gears are welded to the input shaft > the output shaft is welded to
the spider gears > the output shaft is welded to the housing cover.
This creates a solid unit. This is the cheapest way out if you are going
to be drag racing a lot. I would not do it on my daily driver though since it is
a little harsh. Also keep in mind that welding the gears does weaken them ever
so slightly.
Stock differential modified to accept four spider gears > Mark Lang
$595.00 with your good core. May be a very good and
considerably cheaper alternative to the Cusco differential. I have not heard
from anyone that has had it done so I don't know how long they last.
Cusco Center Differential > Buschur Racing
$1550+S&H 4 Spider Gears - more spider gears means more strength.
Kaaz Center Differential
 Diamond-Star Specialties $1300+S&H
Clutch type limited slip - clutches wear (and squeak and groan).
Quaife Center Differential >
Diamond-Star Specialties $1600+S&H
Torsen type limited slip, very strong. My choice if I had the cash.
Other Parts Needed:
- Roll pin for 5th gear fork
- Transmission Fluid
- (2) New 34mm nuts
- (2) Ref#22986S Washers at about $1.50 each.
Special Tools:
- Snap ring pliers (even though the damn snap ring doesn't have holes in it!)
- Gear puller
- ½" Drive impact wrench - Not required, but makes it a lot easier
- 34mm ½" Drive Socket
- 1/8" punch
Getting Started:
- Disconnect the negative battery terminal.
- Place the car securely on jack stands.
- Pull the right front wheel.
- Drain the transmission fluid.
- Pull the right front brake caliper and wire it up out of the way without disconnecting
the fluid line.
- Remove the brake caliper bracket and brake disk.
- Remove the front sway bar link, you'll need the clearance to pull one of the
transmission bolts out.
- Remove the bolts around the outside of the transmission case, many short and two very
long bolts.
Corrected thanks to Paul Lyons on 5/3/2000
Gently tap the first cover off and set it off to the side along with the
reverse brake gear syncro. The syncro will probably fall on the floor when you pull off the cover.
Shown here installed on the 1st cover for safe keeping.
 Tap the roll pin out of the 5th gear fork with the 1/8" punch and remove the fork.
The large clip on the left is one of two holding 5th gear in place.
 Remove the Viscous Coupling with two large flat screwdrivers. It should come out with
little resistance. Remove the two 34mm nuts holding the gears. I used my impact, worked perfectly.
On 5/9/2000 John Christou Sent this helpful suggestion:
I have a trick for taking off the 34 mm nuts without an impact wrench. After
removing the 5th gear fork, put the transmission in any gear, now manually slide the
5th gear collar locking the transmission in 2 gears at once. This is essential
if you want to torque the nut to the correct value on reassembly.
On 5/10/2000 Tony C Sent this information: The two nuts
that are stated in your center diff repair page are 36mm on my
90 Talon instead of 34mm.
On 1/8/2001 Tom Stangl made this suggestion: A simple way to
remove/install the nuts on the shafts is to stick a penny between the gears. The
penny will get SERIOUSLY mangled, but it locks the gears tight without damaging
them. I've reused the same penny to torque the nuts down just by putting in in
the other side of the gears between teeth that match up with the shape of the
mangled penny, but you can just use a new penny if you aren't as cheap as me ;-)
The back side of the viscous coupling.
 Use a flat screwdriver, or two, to pull the gears far enough away from the case to get
the gear puller on them. Be careful! The gears are very hard, and apparently brittle,
steel. I chipped one using the screwdriver only method. Thus my switch to the gear puller
method.
Remove both gears. Remove the three bolts on the front side of the transmission. They each have a ball and
spring that go with them. Not sure if the springs are different rates so I marked mine and
kept all the pieces together.
 
Pull the second case off and remove the center differential.
 Remove the 8 bolts on the differential cover with the impact wrench and get ready to
catch the falling pieces and parts. As you can see from the mangled washers the exploding
spiders did some damage to the housing. It was not very serious (only time will really
tell) in my opinion, so I smoothed the rough parts out with a Dremil tool and called it
good.
Clean everything in parts cleaner (gasoline works just fine) and re-assemble in reverse order with the
new gears and washers. I was lucky enough that mine went back together with very little
difficulty. The spacer on the smaller end gear (21173V in the illustration) was a good fit
and left me with almost zero end play. I was not sure if it was right so I took it to the
local differential repair master (Vince over at Fearless Gear) and he said it looked and felt
great. So I reinstalled it without getting a different spacer.
- Loc-Tight the differential bolts and torque them to at least 40ft-lbs.
- Put the differential back in the transmission.
- Apply any type of mild silicone sealer to the covers when re-installing them.
- Re-install the other gears and viscous coupling. I don't think you can mess this up as
all the parts seem to only go on one way.
- Check for proper operation.
How to avoid ever doing this repair again. Well . . . if you are going to race your
car, it's going to break. So get over it or become a spectator.
Don't dump the pedal on your CFDF clutch at 5500RPM with sticky tires. I
think a fast even slip, at around 4500RPM is about 100 times easier on the whole
driveline, except the clutch. But hey, this job is about the same amount of work
and cost of replacing a clutch anyway, so take your pick.
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