Finally completed my swap and now I'm having a transmission issue.

 

In first third and fifth I get a grinding noise while decelerating. Its fine while normally accelerating unless I push the shifter. When I decelerate it grinds a bunch. Not sure what's going on as I have no idea about transmissions.

Could be the linkage rubbing the driveline

Not sure I know what you mean or how to fix it but I'll look into it! Seems like a pretty weird thing to be happening.

Found it today. When the engine rocks back when engine breaking the u joint of the driveshaft rubs on the shuft linkage. Its been grinding away think i might just let it. Well see how bad it gets. Also should help when I build a pitch stop.

lol, scott nailed it.