D20 not engaging

[jraynolds]

Need some help troubleshooting. My 79 J-10 with 258 and T-18/D20 runs and drives fine in 2wd. Cannot get it to engage in 4hi or 4lo. Hubs are engaged and levers and linkage in shifter are connected and snug (has the factory "U" shifter for the D20). Rods move when shifter is moved. Not sure how to troubleshoot this. Thanks.

[bufurd]

You know you gotta be moving some right? Try unlocking hubs and while your driving don't try to put it in gear but lightly pull back on lever, you should feel it lightly grind the gears. I do this all the time to make sure my Lock-O-Matics are disengaged, I also do it with the hubs locked to see how out of sync my air pressure is front and rear, you'll feel the gears slowly ride over each other, if your air pressure is perfect the gears will both be the same speed making it much easier to get out of 4WD. Point is you can check function while driving, and helps understand that sitting still can make it near impossible to get in 4WD. Your 258, T18, D20 combo is a good one, near my favorite

[jraynolds]

My 79 Chief engages fine sitting still. For the J-10 I have tried engaging sitting still and rocking back and forth, still nothing.

[wiley-moeracing]

could have sheared the lock pin/clip on the shaft, need to pull it apart to inspect.

[78J10honcho]

You could try locking the hubs, lift the front tires and spin them to ensure the shaft spins with them. Then try it with the transfer case engaged and see what it does