Low mileage 2011 f750 Cummins 6.7

[Waterloo]

The SCR doser crystalizes, I don't believe there is much that can be done to them other than replacing. If you do replace, make sure there is no core deposit on it, don't throw it out. The exhaust after treatment can sometimes be cleaned up, the spray pattern is the concern when it injects fuel into the exhaust. There is a parts core deposit on that doser, at least for the ones on our trucks. If your forced regen goes ok, and the numbers are good, the dosers are probably ok. I would think the exhaust doser is fine, it would be the SCR doser I would be concerned about due to the nature of Urea, as it is prone to crystalization.

I would EGR Tuneup, replace those sensors.

SCR Service, inspect or replace the SCR Doser.

Replace U-Joints in drive line, if there is a carrier bearing, replace it, change fluids in pigs, transmission and motor, all new filters. Keep an eye on the pinion seals, may want to replace those too when you do the u-joints if you see any oil weeping around them. Check the wheel/Axle seals too when you have those tires off.

Your issue will be the sitting, that Lot Rot. It does more damage than you can imagine, I know, my truck had it when I bought it.

I would not go anywhere in this truck pulling a trailer until all of these areas are gone over and inspected. It sounds paranoid to some guys, but unfortunately, lot rot is a very real condition that affects many systems on a vehicle.