No two clutch shifts makes me even more curious about the 70 series PS configuration. Would appreciate it if someone would scan a cross section of the RPS34, or its update, out of a service manual and post it.
Typically, powershift tranny clutches operated in pairs or triples in order to provice a specific ratio.
Without seeing a cross section of the RPS34, I would have guessed four clutches working as pairs to provide the three PS ratios of LOW, MEDIUM, AND HIGH.
I was guessing that----Clutches A and B both are engaged to provide LOW but the master clutch picks up the load causing travel forward or reverse. I understand that releasing the master clutch puts the PS in LOW.
For MEDIUM, Clutches A and C both are engaged to provide MEDIUM-- the master and A stays engaged and B drops out and C picks up. This is what I call a single clutch load drop and single clutch load pick up and these tend to be smooth shifts.
My guess was that HIGH is provided by dropping two and picking up two--- A and C drop out and B and D engage. Here, two clucthes drop out and two clutches pick up. As I recall, upshifting into HIGH was the very rough shift on the tractor that I ran. It is tricky to juggle more that two clutches during a shift.
I interept that you are saying that only two clutches are juggled during either of the two shifts up or down--- one drops out and one picks up. I know that a countershaft PS can do this for two consequetive shifts but I thought it takes a complex planetary in order to do the one drop out and one pick up sequence for two shifts in sequence.
Looking forward to better understanding the 70 series PS.
PS My 8830 Ford has an 18 speed countershaft full powershift with 17 upshifts--all computer controlled shifts. For any one ratio, three clutches are engaged.
For 12 of the shifts, one clutch is dropped and one picks up the load--very smooth.
For 4 of the shifts, two clutches are dropped and two pick up--a tad rough.
For one of the shifts, three clutches are dropped and three clutches pick up--very rough even for the computer to handle.