We had been hearing gear whine from the tranny for a while, but hadn't taken the time to check the gear lube levels. With the transmission, transfer case, and rear axle low about a quart each, it was no wonder. We could see where the rear transfer-case output seal may be leaking, and we'll address that in the future. With Clampy back on the ground, Martinez replaced the oil filter and starting filling the engine back up. We decided to try Valvoline's Max Life 10W-40 engine oil. It's recommended for vehicles over 150,000 miles and we're 45,000 past that.