Hey guys I'm new to the diesel world and bought my first cummins last March. And sadly I have the dreaded 68fre transmission. Mine went out at 26,000 miles total failure stripped teeth off of 4th gear. I see alot of people talk about locking out gears but they always are related to towing. I've only towed once with my truck but I like in the mountains of wv and it seems like my truck is so fast to get to 6th gear. Now pulling hills it seems sluggish or lugging. My question is should I lock out gears if running empty as in no trailer? Few times I have I've noticed my trans temp will get up in the 180's. My truck is a daily driver and other than a s&b intake it's completely stock. Pretty sure mine has the 3:73 rear end any info would be appreciated I love my truck but don't want to keep going threw transmission's