Tech Notes:
TECH - FAQ's
Toyota 4x4 Gears and Differentials
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.
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 trucks 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 compartment firewall.
LC ENGINEERING TOYOTA VIN PLATE
Above is a typical 1989 and later VIN plate, located on the driver's door jam. This one is from a 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.
LC ENGINEERING VIN PLATE TOYOTA
Above is a typcial earlier model Toyota VIN plate, located on the engine compartment fire wall. This is from a 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.
LC ENGINEERING TOYOTYA VIN PLATE
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 Tacoma 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.We have included most of the
common gear codes found in both 4X4's and 4X2's, but there might be a code which We have not listed.
Most Toyotas built through the early 1990s
First Letter, Denotes
Gear Size
Second and Third
Number, Denotes
Gear Ratio
Fourth Number (Letter on later model trucks),
Denotes Pinion Type and Whether Open or LSD
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 We've seen 8" diffs installed from the factory on several base model 1986 Toyota 2WDs.
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
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.
Most Toyotas build from the early 1990s through today.
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.
We'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.
01 = 3.42
02 = 3.58
03 = 4.10
04 = 4.56
05 = 3.15
06 = 3.91
07 = 4.30*
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.
A = 2 Pinion, Open Diff?
B = 4 Pinion, Open Diff?
C = 2 Pinion, LSD ?
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.
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 We base our 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 4x4's, with either a 5
speed manual or overdrive automatic made through 1995. While We 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.
TIRES
SELECTION A
SELECTION B
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
