Need experienced tech help for a strange problem with the Powershift (RPS) in our 2470 >>>>
History: We temporarily overfilled the oil supply in the RPS/Tranny/Hydraulic system in an effort to make a home-made 3-Point forklift fully extend. The unit has a one-way cylinder, 6 inch dia x 8' long so it takes alot of oil to fully extend it. Then we modified the plumbing and seals on the big cylinder to make it into a 2-way so the oil required would be minimal and the tractor control valves and hookups would work properly. Did all this last fall and forgot that the hydraulic oil supply in the tranny may still be overfilled.
While heavy discing this spring the hydraulic oil became over heated, per the dash panel gage. Powershift did not malfunction at all during the overheat. Realized the excess heat may be because of the overfill so I drained the excess. About 5-6 gallons.
Now the RPS delays engagement into 1st or Rev. gear when the "inching pedal" (clutch) is let up. When it finally engages it does it too-fast and hard especially if the throttle is up a little. The trans pressure gage shows too low (in the red) during the delay but jumps to green when it engages. Also, intermediate (2nd) powershift gear won't engage after roll out. Per the gage the oil pressure drops off? But it will engage High (3rd) powershift gear once rolling, if the lever move thru 2nd gear quickly.
Investigation So Far:
Filters are OK, even per the filter pressure gage.
Front & Rear Steering and Remote Hydraulics also work normal.
Oil level is now just above Full with implement cylinders extended. Disc 22 acres of light ground where the machine can pull High (3rd) RPS gear and all was normal. Never overheated or lost oil pressure.
Studied the Service manual and found:
The C1 & C2 clutches are engages for Low RPS gear.
The C1 & C3 clutches are engaged for 2nd RPS gear.
The C2 & C3 clutches are engaged foe High gear.
Now I'm confused because it seems all clutches are operating because Low & High work OK.
I suspect somehow the control circuit must be stuck somewhere.
Any advice guys?