This may sound a bit odd, but take into account my last daily driver was a 90 tbird sc with the AOD tranny. anyone familiar with this will understand why I ask.

Is it okay to use D for daily road driving? or will you chance burning out anything?

91 XJ I6 auto stock (so far)

 

If you mean to drive around allthe time without overdrive,then the only thing you will break is your wallet on the extra fuel

 

D in an XJ is for Daily driving. If you have oversized tires, it is sometimes helpfull to use 3 when going up hills, just to keep it from kicking in and out of 4 gear (OD) all the time.