Originally Posted by
82F100SWB
Twin I-beam is the 2wd front suspension, and you will still find it under 2wd S/D's and 250 and bigger E-Series vans.
TTB was an 80-97 only thing. The dates on the F350's having TTB are correct.
Indeed. One correction tho,TTB and twin I-beam is the same thing - TTB is the name of the overall design, and it can be had in I-beams (2wd) or hollow formed beams (4x4).