I have wheeled excavator Case IH Poclain 888BP 1994 model. There was a problem with switching to high speed, before it turned on from the first time, then from the tenth, now it stopped altogether. Although when high speed was turned on, the excavator drove normally, but it was difficult to turn on. This is a problem with the solenoid valves that switch the hydraulics, and the question is where they are located and what they are controlled by and can something interfere with the switching?
Sorry as I don't have any parts or service information for these machines but the hydraulic motor may be rexroth type. these motors often had both electrical speed change and also had auto speed change. sometimes the motor can get contamination marks in its head cover and stop the motor from changing its displacement and therefor no speed change to high. Best regards
I inspected the transmission with the hydraulic motor, there are no electronics there, only hydraulic hoses and tubes, maybe it's a mechanical problem with me, because when there was a problem that after a few times it would shift, there were noticeable sounds in the transmission as it tried to engage, and then when it did engage, the rabbit light would come on, but there was a similar problem when a high gear was already engaged, it was hard to shift to a low gear, I heard that there is something in the transmission that can get dirty and because of that the gears don't shift. What could it be, where should I look? Maybe there is some hydraulic filter that is clogged and doesn't have enough pressure to engage P.s Sorry for my bad english. Best regards
No problem, your English is very good. I would think the same as you and there may be a pressure related issue but its hard without any information like parts breakdowns or diagrams. I will keep any eye out and if I find any information that could be useful I will post it to you. Best regards
I forgot to write, I solved the problem, I took a multimeter and bought a Unit UT682D wiring tester, checked if there was a signal from the speed switch button, then the main board, everything was fine. After that, I decided to remove it, it turned out that there was no electronics on the board, only kilometers of wires, and I also saw several large relays behind the board, I took my new Unit UT682D tester and found one of the relays to which the signal from the button goes. I removed it and it had 6 contacts. When I removed it, I applied 24V to it from the battery, nothing, silence. I disassembled the relay housing and it turned out that the coil had burned out and at the same time I understood how this relay works. It only needs a pulse to the coil to switch between modes, and there was a button that stuck in the on position, which is why the relay burned out. When I started the engine on the excavator, I pressed the contact in the relay with my hand to switch, and suddenly the speed switched to bunny with a corresponding sound in the gearbox, when I pressed it again, it switched to turtle immediately. It switches modes now well, below I will attach a photo of this relay