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.
NOTE: 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.
The different types of Toyota pick-up differentials
The 1st Toyota IFS Differential (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.
Dissassembled ADD IFS differential.
Non-ADD differential with non-ADD axle tube.
Complete IFS differential. This unit is an ADD differential, but with a swapped on non-ADD axle tube, for use with manual hubs.
Inside a stock IFS differential with 4.10 gears.
Inside an IFS differential with 5.29 gears and aDetroit Truetrac limited slip differential.
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 differentials. 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 differential.
Solid Front and Rear Axle Differentials
This is a solid front axle. Here is an example of an 1985 or older solid front axle with a stock 2 pinion differential.
This is also a solid front axle, but the differential is now a Land Cruiser FZJ80 high pinion, 4 pinion differential, with an ARB air locker installed. This is the only type Land Cruiser differential that is compatable with Toyota pick-ups and 4Runners.
An example of a rear V-6 or Turbo 4 pinion differential. Note the 4 visible fins cast into the differential. 2 pinion differentialss only have 3 fins, like the first differential on the solid front axle in the top picture.
Toyota Transmission Gear Ratios
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!
Toyota Transmission Application Table & Input Bearing Identification Chart
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