My DB has a replacement A112 with 70hp. It was raced in the 70s and 80s.
The gearbox is a 600D but with 11/39 (3..54) final drive. I had it installed to increase top end speed which was lacking with the existing 9/39 (4.33) final drive.
I have noticed whining in 3rd and 4th gears above 4000 rpm.
Of course, knowing these boxes were designed for much less HP and torque, I am wondering if this would be an expected result. I do drive with this in mind. Not agressive starts, or maximum acceleration.
I try to minimize strain on the drive components.
Anybody else have this issue?
Thank you.
Scott
Joe, thank you. A relief to hear. Scott
Scott, I was 115hp at the crank on my A112 in the race car. I never broke the box. I would shift between 7 and 8k. I never hammered the shifts, but I wasn't gentle either. I ran the add on 5th gear as well which is an overhung design which is not strong. Never broke that either. Tough little box!
The whining is really mostly a function of the gear mesh. I don't think it hurts anything.