I own a 2005 Dodge 3500 Quad Cab Laramie 4x4 diesel/ automatic trans. This is strictly a towing vehicle, and it does an amazing job at it. We've only put 24,000 miles on it so far, but I have noticed the transmission shifts very strangely, almost as if it 'double shifts' between gears? I pull a 39 foot, 3 horse Sundowner living quarters trailer with it and it pulls just fine, but when it shifts from 2-3 it will basically shift twice very rapidly (Like it hits a sub gear for a split second). Then once in third gear you must wrap the engine up to around 2,700-2,900 RPM then completely take your foot off of the accelerator for it to 'doublt shift' again into overdrive with a load. Once in overdrive it will drop your RPM's to about 1,700-1,800 and the true torque of the Cummins engine shows up and it pulls right on after that.
We've had 3 Dodge trucks so far and this one is the best pulling truck so far. The only modification I have done is I cut out the stock muffler and installed an Aero Turbine muffler to free up the exhuast a bit. I am just curious to see if anyone else has a similar truck that has noticed similar characteristics? I'm assuming it is completely normal, there are no clunks or rattles, just quick, noticeable shifts. This truck is perfect, except the four speed auto trans could use a gear or two more.... But for what it is, it does an outstanding job and it has outpulled numerous Fords down the interstate.