Loud clanking sound and lights dimming with sound

This was an inexpensive part with high probability of needing it, so I ordered it before beginning to take the washer machine apart based on "noisy" symptom. The fabric softener cup pulled straight up easily with no tool. Then, the agitator pulled straight up easily with no tool. The bolt was easy to get to with socket set and the coupler pulled up using 2 small pieces of wood as levers to pull it up evenly and straight. This didn't solve my noise problem, but was an easy and inexpensive fix to try. FYI...when I continued trying to troubleshoot, I took the belt off and the noise stopped, so I think the transmission is my problem. I tried for 2 days with WD-40, then with C-L-R to get the hub nut to move, and couldn't. I then tried to split the nut using a screwdriver and a hammer and it appears to be split in 2 places, but the nut still won't budge. I listed the washer on craigslist today too frustrated with the hub nut to continue the repair job. The cost of a repairman plus the transmission would have been over half of a new washer machine, and I still would have had a 8+ year-old motor, and I ran across a great deal on a scratch and dent model at Sears, so I am replacing the washer instead of repairing it.