I have a 1977 f-150 with a rebuilt 400M, np 203 transfer case, C6 transmission. Everything is either new or rebuilt on this truck. C6 is on a fresh rebuild, as well as the 203 tcase. My problem is after finally getting everything finished up yesterday, took it for about 6 mile drive to check everything. Ran perfect, no leaks, no issues. Today I pulled it back into the shed to check timing and after setting all day tried to back it out and nothing. Will not move at all, fluid is fresh and at the correct level, linkage seems to be working as it should, I just can't get it to move and I am lost.

 

Did the transfer case get pushed into Neutral?

If that is ok remove a cooler line at the rad and fire it up.

If there is good flow the pump is ok.

Next would be to drop the pan and have a look at the linkage.

 

After a long sleepless night it seems the problem is in the transfer case, somehow it is stuck in neutral and I can get it shifted out. The transfer case is has about 6 miles on a rebuild, so I guess my next plan is to remove the linkage and see if I can get it out of neutral.

 

Found the linkage bound up. Thanks everyone