We are currently working on a web site and at Sierra off-road Services we are open to repairs on all makes, welding,engine,drivetrain and component repairs especialy the older cats,as for computer controls and E.C.M's we will be glad to discuss any issues you might have and will take on problems on a case by case basis as some problems can be very time consuming.We also have a small inventory of 540A tucker parts available for repair jobs if necessary. You can reach me at this time through E-mail at sosdwyer@ hotmail.com. Looking forward to helping you with any future problems you might have.