synthetic is the way to go after a rebuild!!! by far!!! i did it and o my.... its a beauty but i wouldnt switch it mid life like that.
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1987 SR5 rebuilt 2.4ltr, custom front and rear bumpers, ball joint spacers, coil spring rear lift, 4.88 gears, 33x12.5x15 General Grabbers AT2's, bunch other goodies- SOLD.........
1997 SR5 4runner, 3.4, 5 speed, 4x4, 265/75/16's on Tacoma TRD rims, pretty stock....but not for long