Newbie needing advice

[Tim M]

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 live 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

 

[Sam 15]

First off, welcome to the forum. I have a forth gen with a 66fre with 6.4 hemi. My trans temp runs 170-180. I have always been told if the tramsmission starts "hunting" then lock out a gear whether you are towing or not. My understanding, 180 is not too hot...220 is when the fluid breaks down and damage the transmission. I'm not familar with diesels but have to think there is a big difference on how transmissions between the two act due to opperating rpm's.