Jason, to be honest, I've only had the 4R since July, so haven't had to really tear into it, other than getting the truck on a maintenance schedule, given no records. The truck has had only 3 owners (I'm #3; #2 had it for only 2 months)--a real grocery getter.

I can say this, without a teardown:

No ABS light when keyed
No ABS sensor on rear axle
Doing a hard brake from 60 mph does not result in ABS activation
No associated relays, etc are mounted in the engine compartment

I'll try and source for you where I discovered ABS was an option for the 2.7L 4x4, and edit this.

EDIT: 3rd gen info There are a couple other personal sites which have the ABS-optional mentioned; but this is a good writeup overall.

Eighty-eight, yeah, I looked for the ABS components with some help from the FSM, that's one of the reasons I'm fairly sure I don't have ABS. BTW that hard stop from 60 mph I managed in less than 200 feet; I didn't baby it. <img src="/forums/images/graemlins/notooth.gif" alt="" /> Picture an 800 pound moose launching out of the willows....