1984dually
Full Access Member
- Joined
- Aug 31, 2013
- Posts
- 247
- Reaction score
- 57
- Location
- Malin OR
- First Name
- Danny
- Truck Year
- 1984
- Truck Model
- C30
- Engine Size
- 8.1L
1984dually, 8.1l/nv4500/ Doug Nash underdrive. Current 70hd has 4.56 gears and want to go to 3.54. underdrive unit will drop the ratio to around 4.56 when towing. Can change the carrier and gears in the hd but have a 70u from a ford that is 3.54. Anybody use a 70u? Know it uses dana 60 carrier/pinion bearings and possibly a smaller size pinion. Opinions on strength of u vs hd rear ends. Moving pads etc not a problem.
