I am hoping to be running 36s on my FJ62 after I get the SOA. I am going to be running the stock 3F-EFI and auto tranny. My question is what is the best diff. ratio to run with this set up. I use this truck as a dialy driver. I am thinking 5.29s, but I have heard SCARY things about them like severe GRINDING! Is this true? Are they reliable? Any information is greatly appreciated.
Thanks

I think you'd be better-off with 4.88s. They will keep your speedometer close, and you should be low enough with the 4.88s. And that way you don't have to grind the hell out of it. If you really want to go with the 5.29s, just be patient and do a decent grinding job. Then you won't have many strength issues with the missing materials. Somebody had a picture of a super-nice grind a while back. Maybe somebody will re-post it or you can find it with "search".

Do the math first. 5.29 are a 28.7% reduction from the original 4.11's. If you take that adjustment to the original tire size (28's), you end up with 36" tires. That means that running 5.29's in the differentials will allow you to run the 36's at the same RPM's that you were running the stock tires with the stock gears.
Personally, I'd stay with 4.88's and address the crawl ratio through another method, say, an NP203 crawler box? Not only will you get the reduction when you need it, it also extended your drivetrain length and reduces the length of the rear driveshaft, which you'll notice (after the SO) is a little exposed. The prototype for the NP203 mated to the A440F auto tranny and split-case is already out there (being tested as we speak in CO), so it should be available soon.

Thanks for the help. I'm pretty sure I will take your advice and run the 4.88s, but that means I will be relying 100% on the production of the NP203 + AA40F. Hey Henery, who could I speak to about this adapter?
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i run a set of 5.29 with 38 sxs on my fj62. it is still pretty doggy on the road. and could stand to be lower off road. i ripped out my rear endlast month and just figured it had broke where i had ground the shit out of it. i was wrong, the ring gear had held up fine the spider gear[that were welded] broke free. hell i just welded the hell out of it this time and put it back together. the best thing would be to get a full float out of a 80 series and no grinding required. my speedo was pretty much dead on with a wore out set of 38x12.5 sxs. but i just got a new set of 38.5x14.5sxs for it. so it will be a bit slow. the main thing it get used to being slow, it can still out run the zuks but not by much. so theres my 2 cents mike

Wagondriver, the guy to talk to is Jerry Nichols, he was behind the development of the NP203 reduction box for the split-case and is closely involved with the development of the adapter kit for the A440F. He can also give you hard information on schedule, costs, etc... Drop him a note at:
Jerry Nichols: <clcrocks@pcisys.net>

HTH!