Toyota 4×4 Gears and Differentials

Toyota 4×4 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 addedwithout changing to the proper gearsmore power is needed to maintain the same level of highway performance. In additioncrawl speed is decreased. Because our Toyotas are relatively heavy vehicles with relatively low power engineswe don't have a lot of excess power to spareso gearing is very important.

The first thing to dowhen 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 ownerknowing which gears you have is only a quick check of the VIN plate away. On earlier model trucksthe VIN plate is located on the engine comparment firewall. On later (1988 or 1989 and newer) trucksthe 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 itbut not the gear code. On those trucksthe gear code is on a seperate VIN plate located on the engine compartment firewall.

Aboveis a typical 1989 and later VIN platelocated on the driver's door jam. This one is from a 1989 Toyota 4X4. The gear code is circle in red and is G292which indicates an 8" rear diff with 4.10 gears and a 2 pinion carrier.

Aboveis a typcial earlier model Toyota VIN platelocated on the engine compartment fire wall. This is from a 1986 Toyota 4X2 truck. The gear code is circled in white and is G662indicating 3.07 gears and an 8" diff and 2 pinion open carrierwhich is surprising considering that many 4x2 trucks came with 7.5" rear diffs. But some did come with 8" diffs.

Aboveis the VIN plate of a 2001 Tacoma 4x4. All the TacomasT-100sand 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 codeindicates 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 tiresalthough 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 gearsbut this does varydepending on year.

Once the VIN plate is locatedit is time to decode it. The gear code for all Toyota pickupsis a 4 digit code with one letter and three numbers on earlier models and one lettertwo numbers and one letter on later models. Referring to the top example abovethe first letter in the code "G" denotes the ring gear diff size of the rear axle. In this caseit is an 8" ring gear. The second and third digitboth numbers "29" refer to the gear ratio. In this casethe 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 differentialsuntil the Tacoma was introduced in 1995. From 1995 onsome 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'sbut 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 ratiothe next step is to determine which gear ratio is right for your application. This is a highly subjective subjectbut We base our conclusions on the factory ratios. The following chart shows what gear ratio / tire combination will maintain stock or better performancein my opinion. The following applies specifically to 4x4'swith 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 4Runnersthese models did receive higher gearing from the factoryso using this chart would make the rpms significantly higher than what you may be used too.

NOTE: As alwaysif you are unsure which ratio to install in your truckbe sure to seek a second opinion. What you see recommended belowmay not be to your liking depending on your driving .

For factory stock performanceor near factory stock performance with larger tiresselection A should be used with 5 speed manual transmissionsselection B should be used with automatic transmissions. For better off road performance and better highway accelerationselection B should be usedbut 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 ratiocombined with reasonable drivingwill return stock gas mileageon a truck with larger tires.

When regearing with an automatic transmission on pre-1995 trucks that have larger tiresWe recommend going with the next lower gear ratio to maintain factory performance. I.E. if you have 31" tiresyou should use 4.88 gearsif you have 33" tiresyou 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 automaticswhile 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-ups1986-1996 4Runners1993-1998 T-1001998-2005 Hilux 4x4):

When Toyota introduced the IFS suspension in 1986it 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-ups1996 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 Tacoma1996 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 additionthe ADD diffs had a special cage bearing that supported the disconnected axle. As a resultan ADD axle tube cannot be bolted onto a non-ADD diff and be expected work. Howeverif one want to get rid of the ADD system in favor of manual hubsa non-ADD axle tube can be bolted in place of an ADD axle tube on an ADD diff. For this modification to worka 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 differentialbut with a swapped on non-ADD axle tubefor 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 itbut if one could make the Supra diff fit the Toyota frame and swap in the proper gearsthis 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 axlebut the differential is now a Land Cruiser FZJ80 high pinion4 pinion differentialwith an ARB air locker installed. This is the only type Land Cruiser differential that is compatible 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 differentials only have 3 finslike the first differential on the solid front axle in the top picture.

Toyota Transmission Gear Ratios

W56-A-BC? D...? These letters are not used by Toyotaso 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 BibleMarlin 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