I just wanted to follow up with this thread so that it may help out someone else in the future. I spent this weekend pulling my engine to address the grinding noise occurring whenever I downshifted or shifted into reverse. As recommended I purchased a triangle file as well as Mobil 1 Synthetic multipurpose grease (rated to 350F).
Once I had pulled the engine out I closely inspected the input shaft, I found no visible damage to the splines but sprayed them with degreaser to clean them than sprayed with a light coat of spray lube to keep them slippery. Next I pulled the clutch and upon careful inspection found the pilot bearing to be rather dirty and dry, also on the input shaft on the end the smooth bit was showing a bit of burning. I cleaned the pilot bearing, with spray lube and a rag (as well as Q tips) and when the Q tips stopped coming out black I packed the bearing with A LOT of grease.
A month or so ago I had replaced a section of the clutch tubing and I had a hunch that I had left the clutch tubing to long therefore bending the Bowden tube at to extreme of an angle. After carefully reading the Bentley manual I discovered that a dragging clutch (grinding noises) could be the result of having to much of a bend in the Bowden tube. So I cut about ½ inch off the end of my clutch tube and reinstalled the Bowden tube. It was much easier to get in and this time the clutch cable actually stuck through the eyelet of the clutch arm about ¼ of an inch, just enough for me to get the wing nut on the end.
After re-installing the engine, and checking and maintaining a few other odds and ends I took my bus out for a drive. No more grinding while down shifting and no grinding when shifting into reverse also overall shifting feels smoother.
Two things to note is that at first I could not get the bus into gear when I first tried to drive it. I put it in reverse (with the engine off) and backed up for about 20 feet, after that no problem. I have no idea what caused this but I have not experienced any problems since. Also I have a 1969 1600 SP (fully stock) and the Pilot Bearing is behind the Gland Nut, to remove the pilot bearing you have to pull the gland nut (you will need a torque multiplier
www.aircooled.net has one that you can rent for CHEAP if you don’t want to buy one)
Thank you to everyone that offered up advice and encouragement it is greatly appreciated.
Isaac T.
Love & Good Road