1987 trojan 1900z transmission works great in 1st and 2nd gear, but no 3rd or 4th gear in forward or reverse. 3rd and 4th gear goes to neutral basically when shifted to them. anyone have any insight as to what to check on the shifter to verify correct voltage, and where to check on transmission for voltage at the solenoids? if i have correct voltage at the correct solenoids, can i ohm the solenoids to verify failure?
Hi 87Trojan, I'm not sure wether there is an issue on electric system. I'd rather check the hydraulical/mechanical side of transmission. Is K3 able to transmit torque? Check pressure in K3 in 3rd,4th Forward, 3rd Reverse.
ill check it later this week when the rain lets up. i was originally thinking an electrical issue since 3rd, 4th forward and reverse 3rd use the I on the switch to energize if im reading that correctly? i can check pressure at 58 and see if its gettting pressure if im getting pressure, its probably the 3rd clutch has failed? and should i have 12v at 5 or 6 at the connection box?
i was able to run out and test it at port 58. i have 165 psi roughly in 3rd, 4th forward, and 3rd reverse.
Hmmm, 165 psi is not very much, but should be able to transmit some torque. I'd expect around 210 psi at low idle. How is pressure at port 65 in the other gears? With no voltage to control valve there is pressure on K3 as soon as you start engine. Filter is clean?
yes, 165 in neutral as well. i checked port 65 and it shows about 170 psi. we replaced the remote filter, is there a screen that wee need to check as well? do i need to check converter pressure to see if it is higher than control pressure? thanks for the help.
Cut open the old filter to check the paper for debris. I'm wondering why your transmission moves in 1st and 2nd, no drive in 3rd and 4th where K3 is active. Does KV drop in pressure in 3rd? Basically two clutches need to be pressurized for drive. Check of converter pressure doesn't make sense from my point of view. So check pressure in KV (and K3) in 3rd, K4 and K3 in 4th.
pressures in kv and k3 in 3rd were both 165 with no drop. k4 and k3 were both 165 in 4th with no drop. i havent cut open the old filter, but after we replaced the filter and topped off the fluid, we have 3rd and 4th gear. im wondering if the pressure should be higher as well. 3rd and 4th gear ran good on flat ground, but on a slight incline we noticed some slipping and clutch smell. im thinking maybe the pressure control circuit maybe leaking off some pressure in the valve body possibly?
i saw on another forum you responded to about the transmission fluid. ours has red transmission fluid in it. would switching to a 15w40 engine oil maybe cure our issue? thanks again.
The red fluid is ATF (automatic transmission fluid), which is not the stuff ZF recommended. Friction coefficient in clutches is okay with ATF, but rather thin (not positive for lifetime of bearings). So please go for engine oil, 15W40 is fine. Another thing as system pressure is rather low. See image valve top right (pressure control valve) Possibly one of the springs is broken. Take away flat rear plate from control block. Attention: There is some spring force on plate, loosen bolts evenly, flat gasket might be damaged. Hope you got some paper gasket sheet to cut a spare. I'd add 1 or 2 mm on big spring to increase pressure. Or try to get new (similar) springs.
Thank you. I'll look at it this week, and let you know what I find.