The WJ's utilize 3 different T.C.'s. The 242 = Viscious Coupler(Select-Trac), The 247(Quadratrac-II)= Progressive Coupler, and The 249(Quadratrac)= Viscious Coupler.
Oh and... the Progressive Couplers DO burn out on the 247's, mine did and I had to replace it.
'99 4.7 WJ,
3" IRO/Addco rear sway bar/ 31x10.5 Pro Comp XMT's(Yes, I changed my mind and decided on these)/ Pro Comp Mountain Crawler soft 8's 15x7 w/3.75" BS
242 in my garage... still