NP205 - 700R4 Shift Sweet Spot

[beanious]

Hello all, I've been looking for smoother shifting from my NP205.

First I swapped from straight gear oil to Valvoline Synchro mesh gear oil. Which helped, but I still experienced grinding while the engine is running, transmission in neutral and shifting from neutral on the transfer case into high or low.

I had a suspission that the 700R4s experience output shaft rotation when the transmission is in neutral and the engine is running.

I drove to a flat spot, on a dirt road and diisconnected the rear driveshaft at the transfer case. I left it in 2 high, hopped in, started it and put it the transmission in neutral. To my surprise the speedo read 10-11 mph! The speed was RPM dependent, so if I revved the engine above idle the mph on the speedo went up. My best guess is that there's fluid turning in the trans, in turn spinning the output shaft.

After I got the Driveshaft installed all tightened back up, I went out for a drive on the dirt road. I drove at 10 mph, shifted the trans into neutral, then firmly shifted in and out all the gears no problem! The hubs were locked in for the test.

I guess I found the sweet spot for this truck-engine-transmission-transfer case combo. I wanted to pass along what finally worked for me to the community, hopefully it helps out you automatic folks.