I'm a little late to this party but have a question for you. When you did the trans service, did you use all Mopar parts and fluid or aftermarket?
Just curious if that was a give away that something had been done.
Asking as I think I'm in a similar boat with my wife's Ram 2500. We did a trans service on it last summer (with all mopar parts and fluid) and hadn't had any trans issues until last week when it started kicking codes and not wanting to up shift. Currently dealing with codes P0731 through P0735. Her truck is a '14 Ram 2500 CC with the 6.4L, stock 4.10's and 37's (the last 3mos) and 34.5's for the previous 2.5yrs.
I'm hoping we're not too screwed. Local dealer we had the truck towed to automatically laid blame on the 37's for the trans issue. In a week or two planning on having towed to our preferred dealer to take a look at. They're a little more understanding of modded vehicles and have a lot better customer service.
I still want call this dealership a mahf... Anyway, I think if someone tried to determine if the tranny had been serviced previously they could have done so rather easily due to several indicators I had left behind. First indica tor answers your question: I did not use Mopar parts when I did the trans service.
second thing, I broke a pan bolt being lazy and using an Impact driver to reinstall the pan. I wasn't letting the impact hanmer away, the bolts are tiny but whatever i should not have used an impact.
Next, the pan gasket is and was PermaTex (or equivalent) and did I run a leak free perMatex bead but maybe they could tell from there.
If one were diligent those footsteps are not that big a deal to not leave behind, I Just never thought they would hang the issue on me.
I was in there because of the failing trans, the symptoms did not change with the service, good or bad, it Just continued to fail and they knew it would.
I should have never touched it and several said I should not have ever told them that I did. I could have even reinstalled Mopar filters right before I took it back, but I really never thought they would totally shank me with my Lifetime Warranty.
Variation in Perma tex bead and a pan bolt don't prove anything. They probably wouldn't have had anything towards such a claim had I not told them I had done it.
Biggest fail for me was not going into dealership and collecting evidence of" burned" smelling fluid. If I had done that and caught them lying right there, I think they would have paid for the new trans. I did not though, dammit and They never produced any burned fluid evidence, Just claimed it. I smelled the fluid the night before and It smelled normal to me.
In your case I think they have to prove Your 37s were the cause, not just suggest it. There are enough trucks rolling on 37s that you have proof that the trans does handle them and handles them well.
My trans failure was eminent as I imagine yours was to. so Win that ****.
2016 RAM 2500 pw | 392ci w 6spd | CAI w ARH long tubes & Solo | Diablo T2 w HF tune | 5.13 AAM w 35" Mickey MTs | Custom Graphics w illegal tint | Dodge Off-Road