8 speed Transmission dead or something else?

[Ecobummer]

Hey y’all, I have a 2015 eco diesel with 260k miles. Just recently when coming to a complete stop I get a horrible clunk. Doesn’t do it in tow haul mode? Anyhow dealership says it has no codes but they suspect that the lower 1-2 gears are failing. “You should be happy that you got 260k out of it, they are only made for 150k.” Tech guy. Now a lot of people say these trannys are the best part of the truck. Second mechanic opinion said same thing. Dropping low gears. Would you spend the money to drop the fluid and check the valve body and dig a little deeper or just replace it. If you would replace it would you go after market, pull one from a junk yard? Suggestions thanks for your time, Daniel

 

[Ecobummer]

Hey y’all, I have a 2015 eco diesel with 260k miles. Just recently when coming to a complete stop I get a horrible clunk. Doesn’t do it in tow haul mode? Anyhow dealership says it has no codes but they suspect that the lower 1-2 gears are failing. “You should be happy that you got 260k out of it, they are only made for 150k.” Tech guy. Now a lot of people say these trannys are the best part of the truck. Second mechanic opinion said same thing. Dropping low gears. Would you spend the money to drop the fluid and check the valve body and dig a little deeper or just replace it. If you would replace it would you go after market, pull one from a junk yard? Suggestions thanks for your time, Daniel

Replaced fluid and filter at 120k.
light hauling
Temp 180-200. 200 being in tow haul mode.
Shifts through all the gears fine on the up shift. If I do a rolling stop or stop up hill I don’t get any clunking.
Note: today while driving it did make a strange shift and smelt something burning like trans fluid briefly?

 

[v4lu3s]

I would go see a reputable transmission specialist rather than a dealer for this. Given that you have done one service I would lean towards it is just wearing out. I have been doing trans oil and filter every 60k to hopefully see as many miles as possible and where I live it is considered extreme service.