I have a 2005 Lariat Screw 4x4 with 20" wheels and Perelli tires. Between about 35-50 mph the truck ride feels rough..especially if you slightly excelerate. However, if I press the OD lockout button the ride is much smoother. Above 50 the ride is fine. Does this sound like a tranny problem or could it be because the tranny shifts into 4th at to low of a speed? Do you think a tuner like the 1745 would help this? Thanks.

 

What you are feeling are it shifts into 4th at a low speed and locks the torque converter. A locked up TC will create more power. But an unlocked TC will provide a better daily drivability without hindering the transmissions performance.

Contact JusnesModified.com, I'm sure they can create an *ultimate drivability* program for you w/ a bit more power too!