Thanks guys....... Jordan, funny you mentioned that. I was just telling Dean how I have to remove about 2.5mm from the transmission cover so that the sprocket won't bound to it when tightening onto the drive shaft, an another 2mm off the idler mount so that the idler would be inline with the boggies. The thing is that the boggies, tracks, sprockets and idlers are all from Mato, so the problem clearly is between Heng Long chassis and Mato parts.
Don't really know why. Is not like Mato makes their own PzIV, so the parts should work with Heng Long. I have a feeling that Heng Long had different versions of their chassis and Mato was only design to work with one type of them. I am pretty sure Heng Long changed their chassis between the PZ IV D and the F2.