I have a new Quad Cab Hemi 5.7 4X4 with 3.92 gears, 5 speed electronic automatic transmission...The truck has 3,000 miles on it now. While towing trailers in the 2500-3000lb range which I consider relatively light, I use the Tow Haul mode as stated in the owners manual....The transmission seems to constantly search back an forth between 2100 and 2700 rpms...at 60 miles per hour which is about as fast as I can go legally on a two lane highway. Even the slightest knoll or small rise in the road seems to make the trani down shift into the next gear....it goes back and forth several times per minute, it seems even more frequent going into a stiff wind. I do not like this, it is annoying to say the least....I have to believe this may be causing extra wear on the transmission, Is this normal? I have not contacted my dealer yet, want to get some input here first.... I have been burning 87 Octane AMOCO or Mobil, which does not ping at all. Would the octane of the gas play a role here?

 

I had the same problem with my 04 4.7L pulling about 3000-4000 lbs. I wasn't happy at all. My rusty 14 year old GMC (350) with 150k miles on it toyed with this trailer. I expected the towing to at least be adequate on mostly flat interstate roads. But no... the truck switched between 2200 and 3000-3200 RPMs constantly. This was with the tow/haul selector on.

It seemed to be a little better after a couple of hours of towing so I decided to give it another chance before I really start complaing to the dealer.

 

I talked to my dealer today..they said it was "Normal" Normal my ***! They told me after 4,000 miles the "computer" will make an internal adjustment, and this will alleviate itself......For some reason I think this is a crock.....Anyone else have any input on this, I can't be the only Hemi owner with this symptom while towing?

 

my V-6 with the manual towing package has a blurb in it about not towing under any circumstances before the trucks hits 500 miles, and doing so will damage the truck and void the warranty, even if it is set up to tow. No bearing on your deal, I just thought the 4000 mile thing was interesting. There are some guys around the various forums that could confirm or deny that real quick.

 

I have a '02 4.7 reg cab 1500 and the thing would do the down-shift and back up when it was empty with cruise control on at sixty on the slightest hill. I put on a new exhaust and it fixed that. I also seem to remember someone mentioning onthe forum that the computer for the transmission has a "learn" characterists. Seems that the vehicles are getting too smart for their own good. I mentioned the shifting thing to a friend of mine that tows a 66 mustang with a hemi 2500. He said the same thing. Told him about the new exhaust and the way it changed my probs. He went out and got a flowmaster 40 dual system and says it cleared up his prob too.