AS far as the pressures: Did you replace the actuating piston seals and still had the slipping afterward? If your slipping was a result of pressure loss around the seals and you upped the pressures, all that will happen is at some point the seals will blow and NO OD will result. Max pressure within the D type should be no more than what you are currently achieving. Lower is better if the seals can hold it. About 440 to 460 psi.

The reason I mention this is the pump can create much higher pressures than are used by the OD. And the pressure can be high at the measure port and still be lower at the actuating piston area if blowing past the seals and allow slippge. Due to the deisgn of the piston, if the pressures go up the seals should roll slightly and seal better as the pressure goes up.

If I were to rally for 4 hours in the dark, I'd spend the time to make sure the actuating piston seals are new. I'd also tend to keep the pressures at or near design range of 440 to 460 PSI.

I'd also make sure the solenoid is adjusted properly and the operating piston cam is locked on the shaft and not bent out of position. This can cause a lower than normal pressure. If after the above is at spec, raising the pressure by 20 to 40 PSI to prevent slipping would be acceptable. I would not go above the 500 PSI you now have.

Regarding the two different pressure type housings. I am familiar with only one in the D type and that should drop to 40 or lower when not in OD. I would tend to think in the other that does not drop, there is something sticking and not allowing the pressure to bleed off.

The fluid should flow past the operating piston until it is pushed up and the flow blocked. At that point the pressure will build until the relif pressure is met. During that rise the actuating pistons move the sliding member into the brake ring stopping the sun gear and allowing the planetary gears to drive the annullus to over drive the Sprague clutch.

I did survive the weather. Cold weather camping skills are usefull. Not many trees remained intact though. Estimates as high as 80 percent of the trees were damamged. At the worst over 300,000 were without power. As of Sunday night it is estimaed that about 90,000 are still without power.

Duane