So how many miles are we seeing out of the L8T/6L90 Powertrain?

[UltimateToolReviews]

Just curious if we are seeing any high milage examples, been seeing 150-200k+ on Youtube and a few other places. I think the mods (T-stat delete) and keeping up with the transmission fluid service seems to be key. How high of miles have you seen? Sounds like if you didn't get the 10 speed your golden.

[Another JR]

The 6L90 has at least 15 years of excellent service experience  even before this particular installation. My L8T uses less than a pint of oil between 3750 mile interval oil changes. I’m 61, and, barring an accident, I suspect my 2021 3500 will be the last truck I buy. My son already has claimed it when I’m done.  He’ll have to arm wrestle my granddaughter, though. She and I have already caught a lot of salmon while camping with that truck, so she has a legitimate legal claim. 

[No F-bdy Bs]

Provided you don't have one that has the torque converter eat into the housing, it should be a 350k+ truck easy. 

 

I think the 10spd is fine as well. The Allison issues seem to be very rare overall.