Have a 4x2 QC hemi with anti-slip rear, tow package ,and 1600mi.

The truck makes an annoying humming noise at around 40-45 mph. I thought this was the rear end. Other guys have had this ring/pinion adjusted or rear axle replaced and this fixed the problem. I'm not so sure my problem is the same thing.

The problem is that when I am crusing at 40-45 and get into the gas, this increases the humming noise and its like the truck is reluctant to shift. THe rpms are around 1,500 at this point and it seems like the truck __doesnt have enough torque to pull__, but it doesnt want to shift either. Getting into the gas a bit more will just make the noise increase. I have to really get into the gas for it to shift and then the rpms get up to around 2,200 and the truck accelerates and the humming goes away. It feels like there is some extra resistance that keeps it from shifting, but this could be because there is not enough torque at 1500rpms.

The noise isnt really loud, but you can hear it over the AC running on full.

I dont remember this problem with the rental truck I had before buying this truck.

Is this normal?

 

i think you may have something wrong with your od kickdown. at 45+ i belive the trans is programmed to shift up into the od gears. it sounds like it is getting into the od gears, but has trouble getting out to drop down a gear. that would give you the feeling of lost power.
i'm no tranny expert though, so i could be wrong. i hate the trannys in these trucks. i wish it was a five or six speed.

 

1st gear tops out around 45 mph. It might be a stutter from a quick shift to 1st then 2nd.

 

I did some testing today. When I put the truck in tow/haul mode, the truck shifts alot quicker and stays up around 2K rpm. Doesnt seem to be a problem in tow/haul mode.

The problem is when im crusing in normal drive, the rpms will go really low. Cruising at 40mph, the truck is around 1,300 rpms! Guess im saving alot of gas, but i dont like it!