'97 Land Cruiser Engine Not As Fast As It Should Be

[apdhillon]

I have a 1HDT Diesel Engine with five speed and full time transfer case (one which comes with engine). This engine is in a 1997 Land Cruiser (US Model) with locking differential in both the front and rear axles.

The truck with the new engine and transmission runs fine, but it needs taller gears. With the engine RPM at 2000, the truck is only going 46 mph. The engine can pull this truck going at 60 mph at 1800-1900 RPM. How can I achieve this while keeping the locking differential and keeping the stock tires (i.e. the same size). What is available to help my situation?

 

[jynx]

Since you are working with a LC, I might suggest you pose the same question to the 80 series crew. As far as you options, you need to go higher (numerically lower) in the diffs. Most likely you have a 4.10 stock in those factory locked housings, but I am not sure what your options will be in the aftermarket for the locked diffs.

Perhaps someone will know, or maybe someone in the 80 clubhouse can help out. Generally we are looking for torque in an 80 so most are looking to go the other way on gears. Be interested to see what you come up with