[6pack] A Overdrive

[Tom Rand]

Hell Group. I don't often ask for help but here's one.
My over drive quite abruptly driving down the road in 4th gear. Just back shifted and didn't work.
I've cleaned the operating valve, and I'm only seeing about 100 PSI. When it shifts into over drive in actually drops another 25 PSI.
I guess my next step is taking it apart and check the non return valve and accumulator?
Hard to believe this all quit with only 12000 miles on the rebuild. It was working sweet.
1970 TR6
Poland Spring, Maine