I'll check for those error codes this weekend. I'll be getting new front tires to match the back ones and building my own mode switch this weekend.

The howling was high pitched and got louder with gear change. It would go from silent to as loud as it got (loud enough to hear over quiet radio) until the switch to second gear and again go from quiet to loud through second gear etc.

I changed the Transmission fluid about a year ago because I thought that the pulsing might have been the transmission. I have never have put it in 4L. I only use it as a city driver and now that I think I might have a transfer case problem, i'm worried that I might break something.

I've read of guys on here fixing their ABS by changing the ABS module. I can't find anyone who even sells an ABS module. Does it go by another name? Or is this something I can only get from a dealership or junkyard?