FlatbedHemi
Senior Member
Made the plunge several months ago for the 4.88 gear swap, and let me tell you that it makes a world of difference. I made a run towing around 8K lbs over the weekend, and it towed it right along at 80mph without any trouble. Most of the time I didnt even run it in T/H mode, mostly because it locks out 6th gear, which got me to thinking. Is there a way to reprogram the 66RFE behind my 6.4 to shift into 6th when in T/H mode? The trans seemed to do fine, but I would like to have the advantages of the firmer shifting, grade braking, etc. available i T/H mode, but I just dont need it to lock out of 6th because of the lower gears. My truck basically runs 6th gear like a stock 3.73 truck in 5th anyway. Anyone now if this is possible? I know the Cummins guys dont have 6th locked out in the 68RFE. Just wondering if the 66RFE would be programmable to be the same.