Just wanted to let you guys know that are running the older diesels that your injection pump was designed to be lubricated by the sulfur in the fuel. Now that everyone is running on Ultra-Low Sulfur Diesel (ULSD), your old injection pump may not be getting the lube it needs. There are supposed to be additives in the ULSD to compensate for the lack of sulfur in the fuel. This may be fine for your newer diesels, but I would not trust it for older diesels (mid to early 90's or earlier), especially high mileage units. The solution?... Instead of shelling out lots of money on lubrication additives, I just dump in about 4-6 oz. of Automatic Transmission Fluid (ATF) in every tankful. The ATF provides the lubrication needed and burns pretty clean. Maybe your injection pump would be fine without the ATF, but for as cheap as it is, I will not go without it. You get peace of mind and save hundreds on a new injection pump and prevent your truck from being down.