i have a 90 4 runner with the automatic locking hubs. for some reason, it doesnt lock. now, me and my friend did drop a new 22re in it, and maybe we forgot to hook something up. ive been told vacuume, any suggestions?

 

You likely have ADD (or rather your 4Runner). That stands for Automatic Disconnecting Differential. It is all operated by vacuum. If your vac lines aren't hooked up or are wrong, it won't work.

 

yeah, i have the add on my 4runner. ok, so ill start crawling underneith and start looking for hoses.

 

no, don't even do that! remove the A.D.D. system, and bolt on MANUAL LOCKING HUBS!

 

its a little more complicated than that, you have to dig into the axle tube and lock the shift fork/sleeve assy to the inner axle shaft or some folks will swap out axle tubes etc to take things to back to a pre add set up. finding and correcting the vacuum line locations may be easier. just my .02.

lee