There are HP test Ports next to the HP relief valves on the pumps, Its a tiny port, 3mm or 4 mm allen key
Remember HP test is carried out with the brake applied manually using a screwdriver

i have same problem with 393/2004 at 17.080 hours;
have checked quite all besides high pressure, (there aren't pressure test points on HP exits - haven't found point 1 and 2);
low pressure is ok at all test points;
forward starts at little bit higher current - 520 mA;
reverse tarts at 440 mA;
any clue?

17000 hours is alot and that is just the start of problemns. Dont waste your money on it.

It would be the HPV pump. Its not building enough pressure going forward. Im guessing a internal leak. I have a hard time just leaving it. Maybe i commit to taking it apart.....its no good anyway.I could look up drawings.... see if there is rebuild kits.

Are you saing that one of the drive motors at the wheels are bad or the HPV pump that bolts to the engine? I have rebuilt quite a few of the drive motors for the 39X Linde. It is a very simple fixed displacement hydraulic motor. I would be curious as to what would be wrong with it that it works in one direction and not the other. I have not ran across this with a drive motor.

Thanks for your reply. The forklift ended up going to Williams machinery( Linde repair/sales shop) they have done a bunch of testing and it looks like the hydrostate motor is done.The part is $12,000. cnd plus instal. the forklift has 17,000 hrs. Im kinda feeling that the forklift is not worth investing $20,000 to get it working properly.

You could swap the wire connections for the forward (1Y2) and reverse (1Y3) solenoid on the servo cover of the HPV pump. Of the three solenoids this would be the front and back one. The middle solenoid (1Y4) is for the release valve. This would at least let you know if it is an electrical problem prior to the solenoids plugs or a hydraulic problem.