Toyota 4x4
Gears and
Diff Page
Last Update: January 10, 2006
Note to Readers:
This page is in need of an update, which will be forthcoming soon.
Questions about the differential gear ratios and Toyota pickups commonly come up.  It is a very important issue in terms of both
highway and off road performance.   When larger tires are added,  without changing to the proper gears, more power is needed
to maintain the same level of highway performance.  In addition, crawl speed is decreased.  Because our Toyotas are relatively
heavy vehicles with relatively low power engines, we don't have a lot of excess power to spare, so gearing is very important.
Above is a typical 1989 and later VIN plate, located on the driver's door jam.  This one is from my 1989 Toyota 4X4.  The gear code is circle in red and
is G292, which indicates an 8" rear diff with 4.10 gears and a 2 pinion carrier.
Above is typcial earlier model Toyota VIN plate, located on the engine compartment fire wall.  This one is from my brother's 1986 Toyota 4X2 truck.  The
gear code is circled in white and is G662, indicating  3.07 gears and an 8" diff and 2 pinion open carrier, which is surprising considering that many 4x2
trucks came with 7.5" rear diffs.  But some did come with 8" diffs.  I measured his just to confirm it was an 8" carrier, and it was.
Above is the vin plate of a 2001 Tacoma 4x4.  All the Tacomas, T-100s, and Tundras should have a similier looking vin plate located on the driver's
side door jam.

This particular Toyota is my Dad's Tacoma and the gear code (B04A) indicates  8" diff with 4.56 gears and no limited slip.  The transmission code,
indicates that it has an A340F automatic transmission.

Where the vin plate indicates recommened tire pressures is not an indication of which tire size the truck came with.   As this truck came with
265/70R-16 tires.   Many factory 31" tire trucks have vin plates that say 225/75R-15 tires, although some do say 31x10.5-15 tires.  The gear code is the
best indicator of which tires the truck came from the factory with.  Any U.S. sold that came with 4.56 or 4.88 gears came stock with 31x10.5-15 tires or
265/70R-16 tires.   5 speed Tacomas with larger tires typically came with 4.10 gears, but this does vary, depending on year.
Once the VIN plate is located, it is time to decode it.  The gear code for all Toyota pickups, is a 4 digit code with one letter and
three numbers on earlier models and one letter, two numbers and one letter on later models.   Referring to the top example
above, the first letter in the code "G" denotes the ring gear diff size of the rear axle.  In this case, it is an 8" ring gear.  The second
and third digit, both numbers "29" refer to the gear ratio.  In this case, the gear ratio is 4.10.  The fourth and final digit, "2"
denotes the number of pinions of the rear diff and whether the rear diff is an open or LSD type.  In this case the diff is of the open
type.  All U.S. model Toyota pickups were sold with open front and rear differentials, until the Tacoma was introduced in 1995.  
From 1995 on, some Tacomas and 4Runners were equipped with a rear electric locker.
Some overseas Toyotas have come stock with rear limited slips for many years now.

The chart below will help you decode most models of Toyota pickups 4X4s built in Japan and the U.S.  I've included most of the
common gear codes found in both 4X4s and 4X2s, but there might be a code which I have not listed.  For more available gear
codes on Japanese built trucks, check this gear page.
Most Toyotas built through the early 1990s
Second and Third
Number, Denotes
Gear Ratio
Fourth Number (Letter on later model trucks),
Denotes Pinion Type and Whether Open or LSD
First Letter, Denotes
Gear Size
07 = 3.900
08 = 4.110
10 = 4.375
14 = 4.875
25 = 4.556
28 = 4.300
29 = 4.100
31 = 3.91
38 = 3.42
43 = 3.56
54 = 3.90
66 = 3.07
2 = 2 Pinion, Open Diff
3 = 2 Pinion, Limited Slip
4 = 4 Pinion, Open Diff
5 = 4 Pinion, Limited Slip
F = 7.5" gear

G = 8.0" gear
While many 2WD models did get the 7.5" gears, many
also got the 8" rear diff.   It's not clear which models got
these, besides the 1 ton models, but I've seen 8" diffs
installed from the factory on several base model 1986
Toyota 2WDs.
A = 2 Pinion, Open Diff?

B = 4 Pinion, Open Diff?

C = 2 Pinion, LSD ?
01 = 3.42
02 = 3.58
03 = 4.10
04 = 4.56
05 = 3.15
06 = 3.91
07 = 4.30*
A=  See below

B = See below
There doesn't seem to be any rhyme or reason for part of the
later model gear codes found in the Tacomas, T-100s,
4Runners and Tundra.
I've seen both A and B listed on 4x4s.  Toyota did offer two
types of rear diffs on these models.  A new style standard 8"
diff with no locker.  Sometimes referred too as an 8.4" diff, but
in reality uses the same 8" gear as older trucks, but entirely
redesigned and stronger 2 pinion carrier.

Other models came equipped with a special electric locking
diff that used the same carrier design as the older 4 pinion
diffs.  

I originally thought the A and B differentiated between the
two styles, but it apparently does not.
Once again, the final code is not as clear on newer
models as older models.
LSDs were not available in the U.S. until very recently
and then only on the Tundra as a factory option.

I'm not clear on which code an electric locker
equipped truck would have.
The "07" code was introduced in 2000
and it's actual ratio has not been
confirmed, however, Toyota did
reintroduce the 4.30 ratio to the
Tacomas in 2000, so I assume the
mysterious "07" code indicates 4.30,
but this is not confirmed.
Once you've determined your gear ratio, the next step is to determine which gear ratio is right for your application.   This is a
highly subjective subject, but I base my conclusions on the factory ratios.  The following chart shows what gear ratio / tire
combination will maintain stock or better performance, in my opinion.  The following applies specifically to 4x4s, with either a 5
speed manual or overdrive automatic made through 1995.  While I believe it would be applicable to 1996 and later Tacoma's and
4Runners, these models did receive higher gearing from the factory, so using this chart would make the rpms significantly higher
than what you may be used too.   

As always, if you are unsure which ratio to install in your truck, be sure to seek a second opinion.   
What you see recommended below, may not be to your liking depending on  your driving style.
225/70R-15 Tires    =      4.10 or 4.30 gears
31 x 10.5-15 Tires   =     4.56 or 4.88 gears
32 x 11.5-15 Tires   =     4.56 or 4.88 gears
33 x 9.5-15 Tires     =     4.88 or 5.29 gears
33 x 12.5-15 Tires   =     4.88 or 5.29 gears
35 x 12.5-15 Tires  =         5.29 gears    
For factory stock performance, or near factory stock performance with larger tires, selection A should be used with 5
speed manual transmissions, selection B should be used with automatic transmissions.   For better off road
performance and better highway acceleration, selection B should be used, but you will experience  higher rpms on the
highway than you may be used too.  How these ratios affect fuel economy depends entirely on how you drive and the
weight you carry.   In some cases a lower ratio, combined with reasonable driving, will return stock gas mileage, on a
truck with larger tires.
When regearing with an automatic transmission on pre-1995 trucks that have larger tires, I recommend going with the next lower gear ratio to
maintain factory performance.  I.E. if you have 31" tires, you should use 4.88 gears, if you have 33" tires, you should use 5.29 gears.  The
lower gearing is recommended to offset the extremely high 1st gear in the automatic and the high overdrive.  Toyota installed 4.30s in stock
automatics, while similar 5 speed models got 4.10 gears.   This is not as critical on Tacomas since they have more powerful engines.
The different types of Toyota pick-up differentials
The 1st Toyota IFS diff.
1986-1995 pick-ups, 1986-1996 4Runners, 1993-1998 T-100, 1998-2005 Hilux 4x4
When Toyota introduced the IFS suspension in 1986, it had to completely redesign the front diff and diff housing.   Was was
designed is what you see here.  The first Toyota IFS diff for the 4X4.  This exact same design was used in all U.S. model Toyota
pick-up/4Runner 4X4 beginning in 1986.  It's producted lasted through early 1995 on the pick-ups, 1996 on the 4Runners and
1998 on the T100 pick-ups.  It's still in production today and used in the non-U.S. model Hilux 4x4s with IFS.
The 1995 and later Tacoma, 1996 and later 4Runner and the Tundra all use a different type of front diff design.

The same differential is interchangable between all trucks that use this type of IFS with the exception that a non-ADD (Automatic
Disconnecting Differential) diff cannot be substituted for an ADD diff.   The only differences between these types of diffs are that
ADD diffs had a special type of side axle for mounting the ADD hardware.  In addition, the ADD diffs had a special cage bearing
that supported the disconnected axle.   As a result, an ADD axle tube cannot be bolted onto a non-ADD diff and be expected
work.  However, if one want to get rid of the ADD system in favor of manual hubs, a non-ADD axle tube can be bolted in place of
an ADD axle tube on an ADD diff.  For this modification to work, a new side axle seal must be pressed into the ADD diff prior to
bolting on the non-ADD axle tube.
These two pictures below are courtesy of Toy4x.
Non-ADD diff with non-ADD axle tube
Complete IFS diff.  This unit is an ADD diff,
but with a swapped on non-ADD axle tube,
for use with manual hubs
Dissassembled ADD IFS diff
Inside an IFS diff with 5.29 gears and
aDetroit Truetrac limited slip differential
Inside a stock IFS diff with 4.10 gears
An interesting side note.  This is a Toyota
Supra IRS differential from a '86 - '95
Supra.  These diffs came with 4 pinion
carriers and 8" gears and were much
stronger than the 7.5" 4X4 IFS diff above.  
Note the similarities between the two diffs.
 Probably much more work than it would
ever be worth it, but if one could make the
Supra diff fit the Toyota frame and swap in
the proper gears, this would make one
heck of a neat 4x4 IFS diff.
Solid Front and Rear Axle diffs
An example of a rear V-6 or Turbo 4
pinion diff.  Note the 4 visible fins cast
into the diff.  2 pinion diffs only have 3
fins, like the first diff on my solid front
axle in the far left picture.
This is my solid front axle.  Here is an
example of an 1985 or older solid front
axle with a stock 2 pinion diff.
LINKS TO MORE INFO ON GEARS AND DIFFS
(I know some of these are outdated, sorry.)
Selection A    Selection B
The first thing to do, when considering gear ratios and diffs is to determine what gears are on the truck.  If you are relatively
certain that the truck's gear ratios were not changed by the  prior owner, knowing which gears you have is only a quick check of
the VIN plate away.   On earlier model trucks, the VIN plate is located on the engine comparment firewall.  On later (1988 or 1989
and newer) trucks, the VIN plate is locate on the driver's side door jam.   Some earlier truck also have a plate with the Vin number
and misc. information on it, but not the gear code.  On those trucks, the gear code is on a seperate VIN plate located on the
engine compartement firewall.
Most Toyotas build from the early 1990s through today.
Toyota sometimes mistakenly coded trucks with 4 pinion
diffs with a "2" code.  To verify if yours is a 2 or 4 pinion
diff, count the number of fins on each side of the diff.  A 4
pinion diff will have 4 fins on each side.  A 2 pinion will
have 3 fins on each side.

All 1986-1987 turbo 22RE-T trucks/4Runners and 1988
through mid 1995 V-6 trucks should have a factory 4 pinion
diff.
This is also my solid front axle, but the
diff is now a Land Cruiser FZJ80 high
pinion, 4 pinion diff, with an ARB air
locker installed. This is the only type
Land Cruiser diff that is compatable
with Toyota pick-ups and 4Runners.
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