What is the rear differential ratio of a 1998 Lexus GS400?
The rear differential ratio for a typical 1998 Lexus GS400, especially the U.S.-market model with an automatic transmission, is 3.27:1. This final-drive ratio influences highway engine RPM and overall acceleration, but exact figures can vary by market and production run, so it’s important to verify your specific car.
Context: GS400 drivetrain in 1998
The 1998 GS400 used a 1UZ-FE V8 paired with a four-speed automatic transmission, with power conveyed to the rear axle through the differential. While 3.27:1 is the commonly cited value for U.S.-market cars, variations by market, trim, or production batch can occur. If you’re looking at a non-U.S. model or a car with a different specification, the ratio may differ.
Common reference value (US-market automatic)
For enthusiasts and owners trying to confirm gearing, the figure most often cited for the typical U.S.-spec 1998 GS400 with an automatic transmission is:
- 3.27:1 final-drive ratio
Note that market and option differences can yield other ratios; the exact figure should be confirmed on the vehicle itself or in official documentation.
How to confirm the exact ratio on your car
To determine your car’s precise rear differential ratio, use these verification methods. Accuracy matters for maintenance, speedometer calibration, and towing calculations.
- Inspect the differential housing for a data tag or stamping that lists the axle ratio (often shown as "Axle: 3.27" or similar).
- Consult the original owner’s manual or the dealer’s parts diagram for the exact final-drive specification for your VIN and market.
- Use the VIN to pull the factory build data from Lexus databases or request a build sheet from a Lexus dealer; the axle ratio is included in the configuration.
- If documentation isn’t accessible, a qualified technician can read the axle code from the differential or service data plate to confirm the ratio.
Once verified, ensure related measurements (tire size, drivetrain components, and speedometer calibration) are consistent with this final-drive figure.
Summary
The 1998 Lexus GS400’s rear differential is commonly listed as 3.27:1 for U.S.-market cars equipped with an automatic transmission, but exact ratios can vary by market and production year. To be certain, check the vehicle’s data plate, build sheet, or consult a Lexus dealer with the VIN.
