what diff to fit?

[dirty130]

I have a 1986 4runner with a 2.2 4Y engine which has G142 diffs which is a ratio of 4.875 i have some spare diffs which are G252 diffs which has a ratio of 4.556. My question is if i fit the other diffs how will this effect fuel consumption and acceleration?

Thanks Dave

[conversion man]

Unless you fit astronger engine you will be waisting your time because lower rpm does not always give better fuel consumption . If the engine is not strong enough to use the extra (legs) of the ratio you will have to gear back more often .First install a stronger engine .

[dirty130]

found my answer http://www.grimmjeeper.com/gears.html" onclick="window.open(this.href);return false; its very interesting.

[dirty130]

yes i totally agree with you. do you think that changing from 4.875 to 4.556 actually make alot of difference to fuel on the hi way? I live in Queenslands so we do alot of hi ways k's to get anywhere. around the city i think i will suffer. The problem i have at the moment is that the rear diff leaks and wines the front diffs driver side output flang has alot of play in it. My choices are spend $175 each per diff for seals and bearings and fit them my self then get the diffs centered by a professional or just swap the diffs to the spare ones i have which have no play or leaks. I was wondering if anyone had swapped diffs of the simlar ratio and engine size. I am looking a 2.8 turbo diesel conversion in the future but need to make the truck solid first. Thanks for your reply