Questions about transmission swap out

[608KEB 797]

I have a 1975 C-120. I'm going to put in a transmission from a 1973 16 automatic. I am going to go thru the C-120 transmission, needle bearings, seals, new keyways, etc. The 16 auto has a hydro lift. I am not going to use the hydro lift. I read thru the manual and understand that I should switch the springs around in the 2 plugs to reduce pressure build up. Then where do I get 2 more plugs for the eliminated hydro hoses? The instructions in the manual said to remove the cones from the hydro plugs. I don't know what these are I didn't see these cones when i removed the plugs. What do these cones look like? Where can I get 2 hydro plugs? Where or what are the cones that the manual discusses? also if I drain all 6 quarts from the 16 auto tranny of ATF fluid. Can I run 10W-30 oil in this transmission?

[kpinnc 15,689]

You should be able to get O-ring plugs from any hydraulic supply store. Northern tool and Tractor supply may even have them. They are not tapered like pipe thread, so be careful not to use pipe thread plugs.

You can change over to motor oil, just be sure you get ALL of the ATF out of the system. The fluids do not mix.

[608KEB 797]

Thanks for the input. I switched the transmissions with no problems. The next issue is the hydro lever. It is stuck. I had to weld the brace that bolts to the frame. When I fixed this problem, The lever would not move until I loosened up the nut that is on the shaft with the spring. Where would I heat this to free up the lever?

[608KEB 797]

Would I heat up the threads that are in the picture?

[kpinnc 15,689]

If you can get the DCL assembly out, then the area you want to take apart and clean is right where the yellow wire is going- it made a good pointer in this case.

That is a cone-shaped part that sets the friction of the DCL, though it isn't obvious without seeing it apart. They sometimes rust and freeze up, which results in the problems you're having.

Here's a better view of the assembly:

Parts 6-56 and 6-58 tend to rust together over time, so taking them apart and cleaning that up is a good idea.

Good luck!

[608KEB 797]

I heated it up til it was free. I oiled it the best I could from each side. I also backed off the tension on the spring. It works really well! The movement on the lever is smooth. I have a B-100 auto that I'm restoring and I took that lever apart, so I could understand how it works. Thanks KB