1. psoi trac? no they never came with it from the factory. but you can do tests to see if the diff contains a locker or a LSD or some other traction aiding device...

2. yes...

3. to do what?

4. infamous head gasket recall. see if thagt was done on it. otherwise, this truck just needs the normal TLC...

5. look for AILINK, IIRC. i bought a set for my 4runner which uses coils instead of leafs for your truck. they do sell a coil spring assembly to bolt between the frame and the axle... check your local RV shop...

leo d.

90 4runner, v6, auto, WCOR CitB kit,
marlin duals, arb rear, tt front
4.88, blah, blah, blah...

Pres. of TEAM IFS! and
GETTING OFF 4WD Club member