Most Reliable Duramax

[AXE]

Always interesting to see thoughts on reliability, upgrades, and performance of the different Duramax motors from the experts. I've owned the LLY, LML, and L5P. All of mine have been reliable.

Lost a water pump.on the LLY at 100k, sold it with 150k. I liked the LML the best with the tuning and 6 speed transmission and it's still going strong at 100k+. I did have DEF emissions issues with sensors and 9th injector.

Probably too early to say on the L5P, but its certainly the best off the lot performance for power, power delivery, and smooth shifting transmission. If the fake Allison holds up and the oil cooler doesn't leak into coolant system, it's probably a winner.

 

[Paulie-G]

My vote. The LBZ series

 

[Truckie]

I had an LLY with an Allison 6 speed for 19 years and only changed the water pump, brakes, serp belt tensioner/pulleys, a rear axle seal and a couple of glow plugs. Regular oil and fuel filter changes. 235,000 miles later I sold it for $18,000 on Facebook Marketplace in 1 hour. I had someone else post it since I am not on Facebook. I can't argue about the reliability. Hope to get the same out of the L5P.

 

[AXE]

I had an LLY with an Allison 6 speed for 19 years and only changed the water pump, brakes, serp belt tensioner/pulleys, a rear axle seal and a couple of glow plugs. Regular oil and fuel filter changes. 235,000 miles later I sold it for $18,000 on Facebook Marketplace in 1 hour. I had someone else post it since I am not on Facebook. I can't argue about the reliability. Hope to get the same out of the L5P.

My LLY after 10 years and 150k miles. New water pump and idler arm/pitman arm, still had the original brakes and towed plenty with it. Pretty incredible rig.