I started the 78 Elk again today and put it on the road. I didn't go over 45 mph due to that was the speed limit. I chose that route due to when I checked the lock up before it struggled at 25 and the rpms would drop when I flipped the switch on. This trip over 40 the rpms didn't drop and it didn't stumble at 20 mph like it did before. The cruise control worked great at 25, 35 and 45 mph. They are on the same fuse. Any ideas of what is going on?