TTB is IFS Independent front suspension. If a hole is hit with one tire, and only one tire, it is affected, not the other side, which is same to the short and long arm design (A-arms so to speak) on the later explorers. How they specifically work is different, but they are both IFS! On a solid axle, if one tire hits a hole, the other tire is directly affected, as they are directly connected.
Simple as that, TTB is IFS in my book, always will be and both SLA and TTB are completely different than a solid axle...
and its AXLE not axel
Onward we go!