Have a 7800 that bolt broke in bottom control valve on transmission, started to leak but still would drive, removed control valve, removed broken bolt, put back together with new gaskets and plate, now won't move. Have had off and on 4 times. I'm sure I have the shift linkage engaging spools properly. I have pressure to the 1-4 gears no pressure at fwd or reverse, transmission system pressure is at 250 psi and lube is 18 psi. Checking pressure at port marked clutch I have 30 psi with clutch pedal up 0psi with clutch pedal depressed. I took front cover off transmission, removed clutch spool and found spring broken inside and a hole wore in clutch spool. Replaced those pieces and removed and inspected all valves, assembled and no change in pressures.
Last edited by krawler; 10-27-2016 at 12:44 AM.
Reason: missing info
There is a serial number break on the plate and gaskets. Are you sure you have the correct ones? The difference is in the casting number of the valve housing. If you have valve housing R129280, you need gasket and plate RE57465. All other housing number use AR166680 plate and gaskets. There seems to be a conflict in the serial number break, so I would check the casting number instead.
I will double check with casting number as we did use transmission serial number to order gaskets. I'm pretty sure I have the linkage engaged into the fwd/rev spool. The neutral start switch functions properly starts in neutral not in fwd or rev. I purchased the o&t and repair disks. Can't find anything that says the test port marked "clutch" is actually pressure from clutch spool that would be going to fwd/rev spool. Usually when you take something apart and theres a new problem when you put it together its something you did lol.