If you don't have any power to the trans shift solenoids, you should have 3rd gear as both the Solenoid A and Solenoid B are unpowered for 3rd gear on the 60e. For the 80e unpowered results in 2nd gear.
Shift solenoid strategy for the 4l60e/65e/70e
1st gear
Solenoid A=On Solenoid B=On
2nd Gear
A=Off Sol B=On
3rd Gear
A=Off B=Off
4th
A=On B=Off
Reverse
A=On B=On
On gears 2, 3, 4th and Reverse, the 3-2 shift solenoid is On, for Park, Reverse, Neutral 1st gear, it is Off.
For the 80e
1st gear
Solenoid A=On Sol. B=Off
2nd gear
A=Off B=Off
3rd
A=Off B=On
4th
A=On B-On
Reverse
A=On B=Off
The difference between the 2 transmissions is that the Solenoid A strategy is shared and the Solenoid B strategy is inverted.
This makes swapping between the 2 is rather easy wiring wise.
So with the above info you can see if the TCM is actually commanding the shift solenoids, or if its a problem in the trans. Scan tools like the Tech 2 can actually bi-directionally command gear selection and TCC lock/unlock as well.
Any 60e/65e tune should control any 60e/65e trans.
peace
Hog