I have a 2003 Caterpillar GP25K forklift, and recently I've encountered a technical issue with it. Everything starts off normal - the startup is smooth, and it operates correctly for a few minutes. But after a short while, I run into difficulties moving forward. It's frustrating because otherwise, the forklift works perfectly.

I've tried investigating the problem, and I've checked the electrical contacts leading to the solenoid valve responsible for changing the direction of movement. Everything seems fine there. I decided to dismantle the solenoid valve and clean it, hoping that would fix the issue. Unfortunately, it didn't make any difference.

I'm now thinking that the issue might be with the solenoid valve coil. There may be a defect in the coil, which only manifests after the forklift has been running for a while. It would explain why it initially works and then stops moving forward.

Now, the problem is finding a solenoid valve compatible with this forklift model. I've already searched online, but I haven't found clear information about spare parts for this older model.
Can anyone help me to find where I can find this kind of solenoid valve ? I called the dealership, and they said they no longer sell parts for this model.
Please help me.