1611 Install-Toyota Tundra Front Differential by Mike ... - Teddnet.com

1611 Install-Toyota Tundra Front Differential by Mike Donofrio
The problem The solution
The Toyota Tundra is great all-around truck but the front differential is
considered undersized and weak for serious off-roading. When used in
moderate to severe duty conditions it is only a matter of time before even the
occasional Tundra enthusiast finds they that have no four wheel drive, followed
by a diagnosis of shredded spider gears. Repairs are costly and replacing your
original differential with another failure prone open differential is basically asking
for trouble. If your differential is full of metal pieces you will likely need to rebuild
it completely (bearings, seals, thrust washers, etc) If you only find one or two
teeth in your next front differential oil change you have no time to lose! Order up
a Powertrax Lock Right and upgrade to heavy duty today!
These instructions are not meant to replace manufacturer's install instructions
they are only meant as a high level overview to doing the installation specific to a
Toyota 7.5 front differential on a Tundra. This differential is known to have been
used in Tundras, Sequoias, some Tacomas, and some 4Runners and generally
look like this:

Before beginning to do the work you will need the following:
• Vise or clamp table
• LocTite Red and Blue
• I prefer Sierra Gear and Axle brand 100% silicone as a gasket maker
• Medium grease
• 1.4 quarts 75w-90 gear oil
• A sharp chisel and a very small screwdriver will be very helpful
• Jackstands, safety glasses, common sense
• Good set of wrenches, sockets, etc
From Toyota you will need to buy:
• 1pc 90521-29002 Ring, Hole Snap
• 2pc 43425-04020 Ring, Drive Shaft Snap
• 5pc 41222-35030 Plate, Ring Gear
Jack vehicle and secure with jackstands.
Remove wheels.
Remove engine undercover (skidplate).
Remove front diff fill plug (upper) then remove
drain plug (lower) drain gear oil into suitable
container for recycling. 10mm allan wrench.
Remove lower ball joint bolts-4 each side (bolt
shown exposed). 14 mm
Matchmark and
then disconnect
front driveline at
front differential
pinion flange (4
bolts). 14 mm

Disconnect plug for Automatic Differential Disconnect (ADD) and front diff
breather (Not shown).
X=Do not use allan wrench to remove cushion screw
On rear of
differential
remove two
bolts on front
differential rear
cushion. One
facing up (A)
and one facing
down (B).
17mm
Firmly grasp rotor/caliper assembly and pull
entire half shaft out of differential. Be careful
not to damage CV joints. Repeat on other side.
Align half shafts away from differential and be
sure not to tear CV boots on exposed bolts.
Begin to stabilize differential with transmission jack or have a friend hold it while
completing next step. Use caution as diff will be almost completely removed and
may fall causing injury. It weighs close to 100 lbs.
Remove front differential cushion brackets-two
bolts. Pic shown is with differential drop
bracket-OEM design similar.
Remove differential to bench
Remove differential seal bolts.

Using chisel and hammer, pry open front diffworking
your way around it.
Using prybar,
gently pry
carrier
assembly
away from
housing,
again working
your way
around until it
comes free.
Clamp carrier assembly in clamp table or vise, being careful not to mar bearings.
Using a chisel,
tap lock plate
tabs away
from ring gear
bolts then
pound them
flat to make
way for a
socket.
Using 17mm six-sided socket remove ring gear.

Using a chisel, separate ring gear from carrier
assembly, working your way around the ring
gear.
Once ring gear is removed, place in oven on
cookie sheet at 225 degrees until ready to
reinstall.
Drill out metal deformation around pinion shaft
retainer pin with 1/4” drill bit.
Using a suitable tool, drive out retainer pin.

Remove
pinion shaft
and rotate
gears so that
spider gears
fall away.
Remove side
gears and
thrust washers
and save
washers.
Using the old pinion, tap out stub shaft and
remove remaining side gear.
***Follow manufacturer's instructions for exact installation information***
Assemble Lock Right coupler with original thrust
washers apply a liberal amount of heavy grease
to both sides. Then place these into carrier
according to manufacturer's instructions.
Apply grease
to spacer and
place inside of
driver, use
plenty of
grease on slide
pins and spring
holes to keep
pins flush
inside of driver
then place into
the carrier.

Slide shear pin into opposite hole, then place
dual spring assembly into each window. Be
sure springs are seated. Repeat for each shear
pin/spring set. Install pinion shaft making sure
that spacers are clear of pinion shaft, then
slide retainer pin into retainer pin hole.
Use punch to deform hole and secure retainer
pin.
Remove ring gear from oven and drop onto carrier assembly, align holes by
starting a thread or two on ring gear bolts.
Place ring
gear lock
plates over
bolt holes,
apply red
LocTite to
ring gear
bolts, torque,
then tap lock
plates flush
to bolt heads.
Using a scraper, completely clean differential case mating surfaces to remove all
old gasket material. Then clean with solvent such as brake cleaner.
Place new hole snap ring onto end of stub
shaft, place stub shaft into ADD collar
assembly being sure to line up splines on
collar with stub shaft.

Apply generous amount of grease to bearing
race and gently tap until seated.
Pack as much grease as possible into bearings and then place carrier assembly
onto stub shaft which is exposed from ADD side of differential case. Tap with
block of wood and hammer if necessary.
Apply 1/4” bead of Sierra Gear and Axle
Silicone around circumference of mating
surface and around each bolt hole.
Reinstallation procedure: Use blue LocTite on all bolts and torque to
manufacturer's specifications.
Apply a drop
of blue
LocTite to
each
differential
case bolt and
torque to
spec.
1. Place differential back under vehicle, aligning rear differential mounting
cushion.
2. Thread rear mounting cushion-upper bolt a few turns, then thread up lower
bolt a few turns. Return to upper bolt and tighten; then tighten lower bolt.
3. Bolt up front differential cushions-two long bolts
4. Bolt up front differential pinion flange to front driveline
5. Place new snap rings onto ends of axle shafts, then place gob of grease on
each shaft end/snap ring
6. Grasp rotor assembly and have a friend line up axle shafts into differential

case. Use a quick push to thrust axle shaft into differential until shaft is locked
into place and no appreciable gap is detected between CV joint flange and
differential case.
7. Repeat other side.
8. Place 4 bolts into each lower ball joint, LocTite and torque to spec
9. Replace engine undercover (skidplate).
10.Replace wheels and torque to spec.
11.Remove from jackstands.
12.Wait a few hours for silicone to cure then replace drain plug fill with1.4 quarts
of gear oil until oil trickles from fill hole then replace fill plug.
13.Take for a test drive and learn to drive your new Lock Right front end. The
truck will handle differently than it did before so be sure to read all of the Lock
Right owner's manual.
14.Stomp and enjoy, but always be sure to tread lightly!
A special thank you to the following:
Derryl, Kimberly, the Sterling Family, and Momo.