We have a 1997 214S Loader Backhoe and the machine is not shifting into 1st or 2nd from 3rd or 4th once the machine has been running. In order to select 1st or 2nd gear the gear must be preselected when the machine is shut down and let set overnight, then when started up in the morning the machine will function in the preselected gear. We have changed the shift control on the column in the cab and also changed two of the transmission shifting relays located on the transmission. Both the layshaft relay and the forward hi/lo relay have been changed. Relays all have 12volts. Fluid and filter were changed and inspected the screen all were clean and free of debris. Onto the other electrical issues the transmission temperature warning light would activate when transmission was not hot. The horn operates intermittently. The tachometer is intermittent and sometimes the needle bounces erratically. The 4 wheel steering stopped working, after changing 4 wheel steer module the wheels will steer in the selected function but the rear wheels will not center up with the front wheels. Also the wheels will only operate in 4 wheel steer regardless of the selector position. Any input is appreciated, as multiple JCB dealers/service centers are scratching their heads.
I would have a look see at all the earth points from the battery and to the chassis of the machine and have a good look at the wiring harness for damage or rodent attack.Was there any debris to the screen as its odd why selecting the gear the night before makes it work next day as the oil in the box would drain from the clutch pack the only way this would be if the solenoid block on the top of the box is playing up i have had troubles with the solenoid spool its self causing issues may be worth swapping these over on the box or may be get a new gasket and take the valve body off and take a good look see.Just check under each solenoid that you dont have any rust / oil or swelling of the coils between the coils and the spool on each one of the solenoids on the gearbox.I dont think yours will have a speed sensor on the gearbox if it has this would cause issues with changing but i think yours is to old for this(these are either on the output end of the box or just on the side of the box near the back. So i guess you have had gauges on the transmission and all ok . Does the coil for 1 st and 2nd energize ie have power to them when trying to engage as this will help you fault finding which end to look see at you can do this by just having ign on hand brake off and chock wheels to test save having engine running this will enable you to see whats not working. The other issues electrical all points to bad electrics or earth point issues the steering could be a sensor on the axle very common and if the back wont lock out it will be the front switch should have the little led light up if the switch is working you can flash a spanner under it to see if that works quite often the blue part of the end cap gets hit and damaged then they fail and check the electrical plug on the chassis for damage on the switch fly lead. Check alternator as this can reap havoc with the dash panel and also if you have no steer mode lights on dash from memory there is a 3 amp fuse for this. Check the gearbox harness over the top of the gear box its self and does yours have a transmission ecu fitted to the top of the box be a oblong box bolted down to the solenoid area these can causes troubles and also if they have been over tightened .
I have very little knowledge with JCB but some machines take the tack reading from the alternator. Erratic tack needed can be caused by a bad alternator or bad connections. If your alternator is bad your battery voltage may be low. You should be getting 14 to 14.8 volts at the battery terminals when engine is at idle. You should have 12.3 to 12.8 volts at the battery when engine is off after it has sat unused overnight with key and all switches off. A low battery condition could be the cause of all your shifting and some other electrical issues.
Watching I have the same problem with mine first and second works when it wants