New Cummins owner here, with some basic towing questions.

I have never towed much before, besides small boats, utility trailers short distance.

I am also a first time diesel owner.

I just bought a brand new leftover 18 Cummins 2500 in February, and a 29FT Travel Trailer last month. About 8K lbs. loaded.

The wife and I took our first longer trip with it last weekend, 400 miles.

Before we take some more trips this summer I wanted to check in with a few questions I have.

The truck is deleted with EFI Live, and 4 power levels, +30 +60 +90 and +120HP.

I have been daily driving it in +60, and just left it in this setting for the last tow. Is this where I should be?

I just read on this forum some mention of locking out the 6th gear when towing, which I did not do on my last trip.

Was this a mistake? My trans temp when commuting to work is around 160-165. When towing it was up to 170.

I put 35" tires on the truck with the factory 3.42 rear end. I'm thinking this is a less-than-ideal setup for towing?

Should I make it a priority to upgrade to 3.73 or 4.10?

Also, fuel economy commuting has been between 20-21 MPG. The trip with the camper was 12.5, are these pretty typical figures?

I am pretty impressed, but also I am new to this and I'm not sure what is normal.

Finally, not completely towing related, but driving around this truck tuned at +60HP has me a little nervous.

I love the power and fuel economy from the delete, but I have been driving it really easy out of caution, especially with a load.

Should I be this worried about transmission life?

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