I bought a peterbilt 335 a few months ago. It has an Allison auto in it with a C7 cat. It goes good but I don't like the down shifting. I prefer the manuelly downshift myself. All my other trucks have 8LL trannys. I haven't looked into adjusting the Allison at all yet but was wondering if swapping it out for the 8LL would be worth the effort? What are your thoughts Thanks
The Allison tranny is a good transmission but you can never beat the feeling of being able to shift yourself.
Do you mean that it lugs the motor too much? Contact your local Allison house and ask for their engineer to recalibrate the shift points for you. Much cheaper than replacing the whole tranny. If you have it set to go all the way to 6th gear now, you will need to change rear axle ratio or you will lose a lot of top speed. I like shifting, too, for about an hour and then it gets real old. I much prefer the automatics and I do about 50/50 nowadays.