I have two buddies that had issues with the 3.0 diesel. One had the emissions/def issues that took them a few times to get fixed but it’s fine now.
The other buddy had the rear main seal oil leak issue. It’s been 6 months and now they are replacing the motor completely after 3-4 seal replacements. He can’t decide to sell the truck after they fix it and get something else or keep it.
Yeah, how does a person know if new issues, that seem to have become consistent, are going to actually become "fixed"? I loved the 3.0 engine in that truck, had no reason or desire to get rid of it or trade it, but it had me in a real pickle as I had been working out of state already for 3.5 weeks, and it delayed me being able to drive the 1000 mile trip back to MT for 4 freaking weeks with the dealership unable to fix it or even really figure out what was wrong with it. It felt like they were blindfolded throwing darts at the issue.
I do really like this new AT4X, and the 6.2 is more fun to drive. It actually costs me less out of pocket for fuel with the current prices of diesel vs gas. Gas where I live is 65% the cost of diesel, and while the 6.2 doesn't get nearly the mileage, it is still less expensive in fuel costs than the diesel overall. My biggest issue is the 24 gallon tank leaves a range of 350 miles (could probably stretch it to 400 if driving to near empty), where the 3.0 diesel got 500+ range. It is annoying they put a 24 gallon tank in a truck that is gonna get 15 mpg on the hwy. Needed to be at least a 28 gallon tank.
But back to the 3.0 engine - great engine, but mine (and it seems some others on these engines) are having some of the same issues, making the truck unusable. I don't have any other vehicles to drive, for work or personal, besides my truck. I can't afford to be stranded and/or without a driveable vehicle because the on board computer system puts you in limp mode from what could be multiple issues that are hard to diagnose/fix from codes throwing a "service emissions system" thing. And being just beyond 36K miles, they weren't going to fix it under warranty. Even if they did, I can't afford to wait weeks or a month for my truck to be useable.
I hope others don't have the nightmare situation I did. My wife actually has a 2020 AT4 diesel truck (we bought them at the same time), and this problem with mine has got her thinking about getting rid of hers also. She wants a Tahoe/Surburban because we haul a bunch of kids around often and one of those makes more sense for her/us. She loves her truck, but I think we will trade hers off in the next year because of what I went through with mine.
