What would be the first things to check out? It does not want to shift into gear no matter the throttle input. Oil pressures are fine and inside the specifications. If anybody has a workshop manual and could find relevant pages, that would be of great help. Any advice is appreciated.
Be certain that the battery is fully charged and the alternator is working. Electric shift on these machines.
Just had one do this make sure battery charging system is good check to see if you got power to the shifter make sure oil level is good if all that checks out check trans main pressure the one I worked on had a bad shifter but be ready to pay through the nose $1900.00
Thank you all for these suggestions. I will update as the situation develops.
Alright, all pressures are fine and battery and alternator are fine too. Now the machine is able to shift into first gear and into reverse gear, but fails to do so into higher gears. This, I assume, would rule out the gear selector being bad. It is possible that the transmission is broke altogether, but I would rather rule out 'cheaper' problems first .
Often a transmission that will not shift other than 1st speed forward can be a speed sensor issue. Because if the control can’t detect the ground speed then it can’t give an instruction to upshift. I don’t know how the Volvo transmission gets its shift commands but I suspect it’s the same.
Check your speed sensor and engine speed sensor of you getting any accurate readings
check both input and output speeds on the transmission, if it "see's" a difference it won't shift up as it thinks there is slip happening
I got a25c only shift 1 fwd no output speed sensor test ok wiring test ok
are you saying you have no output speed sensor? then that is your problem, you need the transmission ECU to see no - small difference between the input and output speed senors otherwise the ecu will limit shifts because it thinks you have a slipping transmission
Hi can anyone able to tell me how many wires connecting to a BM volvo A25 C transmission. I see there is a wire harness for the retarder and a main wire harness for the transmission. Is that all the wiring I need to check for faults
Something coldcreek reminded me about, the A25C is a very temperamental when it come to the ignition switch. It needs to be a genuine Volvo one ( as a parts supplier we have tried all the Aftermarket ones and they just give problems ) and have no " extra " wiring for example a radio power supply wired into the battery supply to the switch. On the wiring side of things the load sensor that is connected to the fuel injection pump also has an input into the transmission shift and could be worth looking into