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Those of you with BN-1's or center shift transmissions may not be interested in this. I have been troubleshooting overdrive problems for the last couple of weeks. I have had the oil pump and the non-return check valve out a couple of times, and each time I've taken it for a test ride (with a pressure gage installed at the operating valve)it has operated properly, but not developed as much pressure as it should. More than once I reinstalled the cover and carpet, only to find that after a longer drive I had the same problem. The on-line article by Nelson Riedel is a real gift to all of us. My problem is that when cold, the pressure will build to about 300 psi(I know this is low) and everything works (30W non-deter). Gradually (over 10 to 15 miles) the pressure drops and I end up at about 100 psi and can get stuck in overdrive (if I let it cool off it will disengage and work again), or fail to engage. I've done all the easy stuff like change the accumulator o-ring, checked the operating check valve and the non-return check valve (replaced the ball bearings and lapped the seats, the springs are on order), set the operating valve lift with a dial indicator, etc. etc. I finally had what I think is a bright idea and here-by offer it (probably to find that everyone except for me has already done this). To reduce the time and effort it takes to get the transmission cover off by more than half, I took a saws-all and cut the transmission cover in two, just aft of the shift lever hole. I can now remove only the back half and have access to the operating valve cap, solenoid, and operating lever cover without doing the hokey-pokey with the cover to get it over the shift lever and around the hand brake.
It seems to me that if I'm looking at the pressure with the overdrive off and it drops to 100 psi, there has to be a leak in the non-return check valve or the operating valve. It also does not hold any pressure when I park and shut the motor off, it drops right to zero. I'm signing off until I figure this out. Did Rube Goldberg work for Laycock?
It seems to me that if I'm looking at the pressure with the overdrive off and it drops to 100 psi, there has to be a leak in the non-return check valve or the operating valve. It also does not hold any pressure when I park and shut the motor off, it drops right to zero. I'm signing off until I figure this out. Did Rube Goldberg work for Laycock?