93 F150, just rebuilt it. Upgraded the pump and the accumulator.

Gauge shows about 40 lbs at idle, will peak to 120, but won't stay there. Drops to zero when shifting into any gear. Wheels-up test, pressure goes to about 60 lbs max in D.

Symptoms are:
-no reverse
-no 1st or 3rd, best I can tell

Bad front pump?

 

Could be in the valve body, acc pistons 1-2, intermdiate clutch and or intermediate one way clutch. You are def. losing pressure somewhere.
park is 55-60 idle
reverse 75-99 idle
1st 75-99 idle
drive 155-175 @ stall

 

I hate when that happens.

Thanks for the info.