i have a 2005 QC 4.7l with I believe the 5 speed auto. Sometimes when cruising along at around 40-45 mph the tranny downshifts. The rpms goes from about 1600 to 2000. Then after a few seconds it will upshift and drop back to 1500-1600 rpm. Then sometimes when going up a hill(even a gradual grade) the truck will start too slow so I attempt to accelerate. Seems that it takes a bit for this to happen. Too me it seems to downshift kind of abruptly instead of smooth. My Ranger shifted smooth. Is this normal for these trucks or is this an issue? If it is normal is there a way to smooth it out such as a shift kit or having the dealer play with the computer? What kind of monies we talking? Not the most tranny literate.

Thanks,
PEPPERHEAD

TASTE THE HEAT AND ENJOY THE PAIN

 

You're probably just in the zone between overdrive and torque convertor lockup with the speed and RPMs you posted. What i mean is that the transmission is locking both halves of the torque convertor together to give you a 1:1 ration between the flywheel and the transmission. When this happens it means the transmission is not slipping and your fuel mileage will be maximum. Whenever the transmission feels a slight load, it will rev the engine and unlock the torque convertor to provide more torque to pull the load. Around this 40mph, the torque convertor had just locked up and the RPMs are at the minimum and out of the maximum torque range which means it's very easy for the torque convertor to unlock under the slightest load. To solve this problem you should do one of 2 things. Either #1 manually take the truck out of overdrive or #2 speed up. The reason the ranger probably didnt shift out could have been a couple of things. Some torque convertors arent "lockable". Also the ranger was lighter and they tend to put fairly low gearing in them too. The engines are smaller and get better fuel economy so they can afford to put a lower gear to help with power. My friend's 4 cylinder had a 4.10 gear in it. My other friend had a 4.0 v-6 with 3.73 gears. Also if the ranger did downshift it was probably smoother becasue the transmission slipped more. A slipping transmission creates heat. Heat destroys a transmission. The ranger can get away with it because of its light weight. For a heavy truck like a ram, you want nice crisp shifts.

 

If you have the towing package, use the Tow/Haul mode in hilly or mountainous terrain to prevent overworking the transmission.

 

Thanks for the info. It does have the tow package. I have been running a lot lately with the overdrive off due to pretty icy roads around here. Seems to work smoother. Sounds like I'm just running at too low an rpm to have the overdrive on. We live and we learn.