The auto trans is a GM trans, not an allison. The allison is behind the duramax. The trans in this will be a 4l80e, which is a very good trans.
The manual option will be an NV4500.
1993 K3500- 4x4, single cab/long bed, single rear wheels, 4.10 rear end, F vin, GM3 turbo, Nv4500 manual with Luk clutch and single mass conversion, factory red interior.
A few mods: 3" straight pipe, Bosch boost gauge, Bosch glow plugs.
Gone but not forgotten: 2001 silverado 2500hd CC/SB, 4x4, 6.0 vortec, 229k miles when I traded it.