Ok working on my 2000 GMC Jimmy it was making noise so jacked up rear wheels stuck in drive and got under it noise was coming from front axle so removed front drive shaft the noise. Stoped so it in front axle with engine of when I rotate input shaft its trying to lock in. Will spin freely one way but if spin other way will spin a bit than acts like it wants to catch or lock in

 

Ok after reading some post I believe it the 236. 4 button system I think the front axle is not. Releasing / disigaging completely what parts would cause this to happen