Allison auto transmission O/D lockout
If you have the fine Allison 5 sp. auto transmission in your '01 or '02 Chevy/GMC truck, you have noticed that you do not have the ability to lock the Overdrive out and just use the 4th gear. GM has fixed this for'03 by installing an overdrive disable switch from the factory. Check to see if the O/D switch is available through your dealer yet. If not, it should be soon.
'01 2500hd ext. cab, 8.1 litre gas, 5 sp. Allison auto
3.73 rear end
Mag-Hytec rear diff cover
Amsoil Dual by-pass oil filtration system
Amsoil synthetics all around
265 watt AM Solar, Inc. system