Only Baldwin filter on my Mack is on the hydraulic return line...don't think Mack makes a hydraulic filter. Like I said, I use OEM filters whenever possible...ESPECIALLY if there is a warranty on the vehicle. My Fords even get the Motorcraft brand oil...same cost as any other reasonable option, so why not? Especially if there is a warranty. Otherwise, Ford would blame Pennzoil saying it didn't adequately lubricate the engine....Pennzoil would blame Fram saying it was inadequate filtration....and Fram would pass the buck to Ford claiming a manufacturing defect and NOBODY would want to pay for the repairs. This way, it's a Ford engine, Motorcraft (Ford) oil filter, and Motorcraft (Ford) oil. I don't care which branch of your company pays the bill, work it out amongst yourselves and fix my damned engine. I even tried the Bulldog (Mack) brand oil on one oil change. I could only get it by the gallon jug (I prefer 5 gallon buckets) and there was ONLY one place to get it. Not even all of the Mack dealers carry it. So, I ended up back at Rotella...them 5 gallon buckets are available dang near anywhere...Wal-Mart, Tractor Supply Co, Rural King, Bucheits, Orschelens, etc... When I get my shop built, I'll be able to get a 55 gallon drum (and have a place to keep it), as even the 55 gallon barrels are in stock. Brand loyalty ends when I have to make a special trip 40 miles one way to town just to get to the only place that carries the product in the brand name I'm looking for.