Breif Toyota 4x4 history/definition of terms (for North America):
What type of differential does my Toyota 4x4 have? (top)
What's my gear ratio? There are several ways figure it out: (top)
For "open" diffs:
For limited slip (LSD or "posi"), locking differentials, spools, etc.:
Toyota Axle Widths: (top)
(all widths are measured wms-wms, wms=wheel mounting surface)
* Another tidbit: 2wd
4runners, Tacoma PreRunners, T100's, and Tundra's use 6-lug
wheels- same as the 4x4's
(the other 2wd's use 5-lug)
|'79-85 Trucks and 4Runners all have 4-cylinder engines and use what most call the 4cyl 8" diff in the front (the same one they use in the rear)- see "4cyl 8" diff" below.|
|'86-95 IFS trucks and 4Runners, and
all '93-98 T100s use a 7.5" front diff that is
offset to the passenger's side. Later models came with ADD (Automatic Differential
Disconnect) which uses a vacuum actuated mechanism to
disconnect the drivers side axle shaft from the
differential. Carriers and gear sets are interchangeable
between the two different versions (and also happen to be
the same as used in the 2wd Toyota pickup 7.5"
diffs). One difference between ADD and non-ADD diffs is
that the carrier in an ADD differential has needle
bearings supporting the axle shafts at the differential.
The non-ADD diffs did not have this bearing and sometimes
the passenger side axle flange wears the carrier and
becomes loose or wobbly, eventually causing oil leaks,
noise, and possible spider gear damage. ADD and non-ADD
diffs are swappable as are most of their parts.
This makes it possible to change your ADD diff to non-ADD
by simply swapping parts as I've done in the picture to
the right. This is desirable to some people since
some of the ADD stubs are smaller diameter than the
non-ADD stubs and are therefore slightly weaker.
- Passenger's side
- Low pinion
- 27 spline axles
* This diff is based on the 2wd pickup 7.5" rear diff- same internals, different housing.
|'95-03 Tacoma, '00-04 Tundra,
?? Sequoia's, and 96-02 4Runners have a high-pinion
7.5" IFS front diff offset to the drivers side. The
high-pinion design is used so that the rack and pinion
steering and anti-sway bar on these vehicles can run
under the front driveshaft. The housing is a unique
bolt-together design. The carrier inside is exactly the
same as the '86-95 IFS diffs, so LSD's and lockers for it
are also the same. However, since this is a
high-pinion diff, the gears for it are different
(reverse-cut) than the earlier diff. There is an ADD and
non-ADD version of this diff as well.
These diffs use different gear sets than the earlier IFS diff because of the high-pinion design.
- Driver's side
- High pinion
- 27 spline axles
- Bolt-together "clamshell" housing design.
8" IFS diff
|'03+ 4runner, '04+ Tacoma, FJ Cruiser, '05-07 Tundra,
?? Sequoia: 8" IFS diff.
- Driver's side
- Clamshell housing
- 30 spline axles
- Carrier break: 3.91 and up, 3.73 and down.
Posted by RockKrawler of Allpro
|90-97 Landcruiser (FJ-80
and FZJ-80) uses a high pinion, reverse-cut front
diff based on the V6/Turbo rear diff.
The high pinion design allows the steering on these
vehicles to run behind the axle and under the driveshaft.
Carriers (i.e. lockers, LSD's) from the 8" V6/Turbo diffs can be
installed (direct bolt-in) in the hi-pinion diff. The
entire diff is also a direct bolt-in to all front and
rear axles that use an 8" diff.
This diff is desirable to some straight-axle mini-truck and 4runner owners for a couple of reasons. First, the reverse-cut design of the gears is stronger than simply using a rear diff and gears up front as the factory did since its not using the weaker "coast" side of the gears when driving forward. For this reason, this diff is generally only used in the front axle. Second, the hi-pinion design gives very good ground clearance for the pinion and driveshaft as well as improves driveshaft operating angles.
In North America, almost all of these diffs came from the factory with 4.10 gears. Aftermarket gears for this diff are more expensive than most since they are either imported or custom made in limited quantities. At this time 4.88 and 5.29 are the only aftermarket ratios available.
|8" Diff Housing (3rd member) Identification
4cyl has 3 ribs on each side. V6/Turbo has 4 ribs on each side and the trapezoid shaped top rib. T100/Tundra/Tacoma diff has the characteristic bearing truss.
Note- Starting in about '96, the V6 diffs started using a casting that looks nearly the same as the T100/Tundra casting from the outside. However, it doesn't have the trussed bearing cap on the inside, and the outside uses the smaller 8mm mounting studs.
|Axle Housing Identification
has a dome-shaped cover. Diff uses 8mm studs with 12mm
|All pre-'95 4-cylinder 4wd mini-trucks &
4Runners use the Toyota 8" 2-pinion differential
front and rear (except turbo models). This is
known as the "4cyl diff." This diff is
by far the most common diff in older Toyotas.
10mm ring gear bolts
|'86-95 4cyl Turbo and V6*
trucks and 4runners, and ALL '96+ 4Runners
use the Toyota 8" 4-pinion differential in the rear.
This diff is known as the "V6/Turbo diff."
- Stronger housing than the 4cyl diff
'96-up 4runner V6 diffs:
The FACTORY 4.88 V6 diff is unique!
** V6 diffs are swappable with 4cyl and high pinion diffs
|All 2wd and 4wd T100's, '00-06
Tundra's, and ?? Sequoia's use a
newer/stronger 8" 2-pinion diff. Tacoma 4x4's
and Tacoma PreRunner's that don't come with
the electric locker (aka
"non-TRD), as well as V6 Tacoma 4x2's also
came with this diff.
This diff commonly and mistakenly called an 8.4" or 8.25" diff, possibly to imply its extra strength. The ring gear actually measures 8". The extra strength of this diff comes from the bearing cap/truss and large diameter pinion gear shaft.
LSD's available is the TRD/Kazuma clutch-type 3-pinion LSD, the OEM 4-pinion Tundra TRD LSD, and the Detroit Trutrac.
Lockers available are the Powertrax "Lock-right," "No-Slip," ARB Air Locker, Detroit Softlocker.
This diff cannot be fitted to an older style 8" axle because it uses a larger diameter mounting bolt pattern and because more space inside the housing necessary to accommodate the large bearing cap. The different bolt pattern also makes it very impractical to swap in an electric locking Toyota diff (the whole mounting flange would have to be re-done using a special jig).
- Carrier bearing truss and newer housing adds
significant strength over V6 and 4cyl diffs
* 4Runners do NOT use this diff at all. Late-model 4Runners still use the V6 8" diff above.
** This diff is NOT swappable with V6, 4cyl, high-pinion, or electric locking diffs. This diff cannot be fitted to an older style 8" axle because it uses a larger diameter mounting bolt pattern and because more space inside the housing necessary to accommodate the large bearing cap.
|Tundra 9.5"||'07+ Tundra 4.7L V8, Sequoia?
||'07+ Tundra 5.4L V8, Sequoia?|
|A factory option on 3rd Gen. 4Runners, Tacoma 4x4's,
and Tacoma PreRunner 4x2's is an electric locking
rear differential. This diff is a 4-pinon design
based on the Turbo/V6 8" diff
and uses the same gear sets and bearings (except for the
large bearing near the locking mechanism).
These locking diffs can be retrofitted into 8" diff axles if the axle housing is modified (see this article for more info). It cannot be easily retrofitted into a T100/Tundra or open-diff Tacoma style axle housing because the mounting bolt pattern is smaller. It "could" be done by an axle builder by doing major work to the mounting flange, but that is not really a practical option.
- 30 spline pinion on OEM gears, swap pinion flange to 27 spline to use aftermarket gears
|A factory option on 93-97 Landcruiser
FZJ-80's is a hi-pinion electric locking front
differential. It can be installed into modified
8" axle housings, similar to the 4Runner/Tacoma
locker mentioned above. The reverse-cut gear sets for
this diff are the same as for the standard hi-pinion diff mentioned earlier.
These vehicles also had an optional 8.875" REAR electric locker. This one has been retrofitted into other Landcruiser models with considerable effort (see this article), but it doesn't appear to be compatible with any non-Landcruiser vehicles.
Electric Locker Info
|Toyota Electric Locker Links: (sorry some of this is very old)
-4x4wire's electric locker installation article
-Mike Carter's E-locker install
-Ken Emanuel's E-locker install
-Ed & Judy's E-locker install
-Carl Whitmore's CJ2a w/ dual hi-pinion electric lockers
-Landcruiser FJ80 rear locker into FJ55 front
is a great vendor who has a lot of E-locker parts and
|Toyota Electric Locker
(lots of good info in these old emails)
-Karl Bellve and myself
-Scott Muir and myself
-Carl Whitmore (taken from the Toy4x4 list)
|Home-fabbed wiring to control a
Toyota Electric Locker using relays:
(click to enlarge)
Designed by Scott Muir, drawn by Karl Bellve and I
Special Thanks to Karl Bellve and Scott Muir for all the help with the electric locker info!
I would also like to thank Sean (aka "GearMan") at River City Differentials. He has been very helpful and doesn't seem to mind answering my many questions. He and his shop are highly recommended by members of the Toy4x4 mailing list Pirate4x4.com BBS, and others. Let him know his info is being put to good use!
River City Differentials
Rancho Cordova, CA
"ZUK" also has a great Toyota
diff info web page with a ton of practical gear install info:
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