2015 Ranger 570 midsize. Since it was new it cranked over slow & got worse as time went on. Replaced battery once with an AGM battery that helped. Then replaced battery with a car battery that fits a 2011 Honda CRV. That got me more CCA but didn't solve the problem. Removed the starter & disassembled it. This is what I learned & would like to share. The starter doesn't have a drive. Its direct drive. While the engine is running it always spins. The starter has 4 brushes that energize the armature. One brush was stuck in its holder not making contact & another brush was partially stuck making poor contact. I purchased a brand new aftermarket starter for under $75.00 & installed it. Cranks over like a champ & starts great! OEM starter was over $350.00. Didn't want to buy OEM knowing the original was defective. Hope this helps.