Tech Notes:

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.

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.

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.

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

Most Toyotas build from the early 1990s through today.

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.

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, We 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.

TOYOTA TRANSMISSION GEAR RATIO

CHART

W56-A, -B, C? D...?
These letters are not used by Toyota, so where did they come from? Back in the mid 90s Marlin realized he needed a better way to distinguish between the many different W56 transmissions Toyota used from 1985-95. After having compiled the world's first and only RF1A Transfer Case Bible, Marlin Crawler created the now highly popular letter designations for the W56 transmission. The rest as they say is history!