I rebuilt the transmission in my '38 special. Ninety five percent new parts including spacers, detent springs, reverse idler gear, counter gear, sliding gear, and the first and reverse gear, input and output clutch gear and mainshaft bearings. Pre-lubed everything on installation and checked freedom of movement into each position. Finally re installed the transmission in the car and filled it with 140 weight gear oil. Without running, I shifted all positions several times, then started engine and shifted all positions. Drove the car back and forth 15 or 20 feet several times. Drove easy for half a mile while slowly shifting all positions. All seemed fine. Smooth and no noise. However, when having to start from a standing position on a hill, naturally had to give it more gas/rpm as I started off. As I started off I heard a loud whining. But upon shifting into second, all was fine, no noise, as was third. I brought it to a stop, and started off again with foot heavy on gas. It again whined in first, I shifted into second and all was fine. It was fine in third also. Just to recount; In starting off slow and easy I heard no whining. It whined when more power was used to start off. (I suspect whatever is creating the whine is there at all speeds while in first, but just not so prominent at very low speed to make noise.). Back in the shop, I drained the transmission oil. It was very dirty. The oil I had put in was new and clean, (Honey colored). The oil that came out was dark gray, appeared dirty.. No chips, no pieces, but certaintly it appeared dirty. I put a magnet in it, but nothing was attracted. I pulled the shift lever and cover off the top, and could not see any damage. Nothing was loose. Nothing missing, and no scoring was seen. I was able to move both shift shafts and gears normally. My thoughts are that the oil should not be dirty with less than two hours running, and the noise,(I never had a whinning like this before), could the noise be from a gear getting pushed against another object, or the housing when shifted into first ? Any comments or thoughts?