A bit late but hope this is helpful.
For starts, the crush sleeve or solid sleeve don't set the pinion location, only the pinion depth shims do that. The crush sleeve/solid spacer or shoulder as I'll discuss only set the pinion preload, well and I guess ensure the pinion depth doesn't increase by keeping the lower bearing firmly in its race, aka preload
Technically, Toyota never offered a crush-slim eliminator nor a solid sleeve per say. Rather any of the early pinions (anything up to the late model 60 Series) had a built in shoulder that seated the upper/outer bearing, thus to adjust preload you simply shimmed the outer bearing (after setting pinion depth on the lower bearing to pinion or lower bearing race to housing). Most high quality R&P install kits still include the pinion preload shims as part of the kit, I know all the kits we offer do because its not at all uncommon for us to add a locker or rebuild an older 3rd that still utilizes the shouldered pinion.
On the flip side is the newer non-shouldered pinion used in ever late model application and every common aftermarket gearset pretty much across the board. It has the option of using a crush sleeve or if available a solid-spacer that is often produced aftermarket. We started making them for the Land Cruisers 2-3 years ago, and companies like Marlin & All Pro have been making them for the 8" applications for quite some time. These will add the shoulder for the outer pinion bearing much like a shouldered pinion, however the rest between the two bearings exactly like a crush sleeve. Essentially they are just a really thick crush sleeve.
Now, are crush sleeves bad? After all Toyota among countless other applications used them on all of their later builds including 80 Series, 100's, Hi-Lux, Tacoma, etc. Well I don't think they are that bad, especially when installed and setup correctly. While they are easier to setup for a trained diff rebuilder, they are also a bit easier to screw up for a novice mechanic. Also there are cases where the crush sleeve and "re crush" after installation thus leaving little to no preload and slop in the pinion. Another added benefit of the solid-spacer is the ability to replace pinion seals or pinion flanges without havng to be super delicate with the crush sleeve, rather you undo the pinion nut, replace parts an re-torque the pinion nut (checking the preload before and after to be sure). In all the diffs we set up for customers across the US (and outside) I can think of only a couple instances of crush sleeve issues, including on my own FJ40. For that reason I designed some spacers (first production ones for an LC to my knowledge) and put them to the test. Again, does everyone need them or should you tear your diff apart to install them? No. Are they a good peice of mind when setting up gears, sure. My suggestion would be to consult your ring and pinion installer and get his/her opinion on the matter as ultimately they have to set them up and stand behind the work.
