50 ford overdrive question

[JHFORD51]

My Borg Warner OD unit whines while in the locked up, overdrive position. Engages and disengages fine and quiet as a church mouse while in freewheel mode (overdrive electricals removed temporarily). Today I removed the trans and knocked the tailhousing off. I don't see anything wrong. Rollers are smooth, the three little planetary gears look good and turn smooth, no shavings in the drained gear oil. I was running 90W oil. The tailshaft drum where the planetarys ride in also seems fine and where the rollers ride in the drum is smooth with no pits.

Any ideas?

 

[rotorwrench]

A rear axle with backlash problems can make a whine when power is applied to the drive and stop when you let off the power. Low gear can make some noise but 2nd & high should be relatively quiet whether power is applied or not. Is the noise only when shifted into overdrive electrically from high gear or is it same noise in both high gear and in overdrive under power? I take from your description that it gets quiet when you let off the power in OD (free wheel).

Free wheeling was a necessary addition so that the overdrive could function properly but it does allow for some friction or braking action when you let off the throttle with the OD operational. Actual full engine braking only occurs when the overdrive is in the locked out position with the cable pulled out. As far as the electrical system, it's hot when ever the car is running even if the overdrive is locked out. The rail switch will keep the operating solenoid from functioning when locked out unless you have a later unit that doesn't have the rail switch. The shift rail will block the operating solenoid pawl when locked out but the solenoid is still functional electrically on those later units.