i don't understand final drive ratios.

both the '89-'94 v6 trucks and the tacoma v6 5 speed trucks have the same transmission gear ratios. (both are R150F).

the '89-'94 5 speed v6 trucks had a diff ratio of 4.56.
the tacomas come with a diff ratio of 3.9.

why?

because the tacoma had the bigger engine?

so (hypothetically) if i swapped in a 3.4 into a 3.0 truck, would the diff ratios need to be changed to 3.9? or i could keep the 4.56 and get bigger tires to match the factory final drive ratios?


stock 1994 Toyota 4x4 XtraCab v6 SR5 pickup