I've got a bit of unique vehicle and drivetrain combination and I need some help troubleshooting an issue. I have a 1931 Model A tudor sedan with a drivetrain from a mid 80's 2WD Toyota Pickup. The car belongs to my Father-in-law and was already modified before he bought it and he brought it to me to make it run right. I was able to tune up the 22R and make it run smooth without a lot of trouble, it smokes some and probably has a lot of miles on it, but makes good power. My problem now is the five speed transmission, a W55 or W56, I'm not sure which. The drivetrain makes a loud whining noise, only in 4th and 5th gear and only at light load. There is no noise when accelerating or coasting in 4th and 5th. I flushed the gearbox and was able to get the noise to settle down some, but it still does it. Have any of you dealt with this type of noise and what can be done to fix it?