Cat Lift Trucks (& Caterpillar) DP25K:
Transmission Gremlins

Hello all,
We have a Cat DP 25K, serial AT18B05792, Dec., '02 mfg day.
We seem to be having an interesting Transmission gremlin, that comes and goes. We guess it is an electrical issue, and was hoping for some insight on where to look before cutting the loom.

The forklift will randomly not go into forward, and try to creep backwards in neutral. We have changed the solenoid, pulled the valve body, cleaned, made sure all valves moved, no broken springs or bits. We cleaned trans SST filter and magnets. new fluid and some lucas "Trans fix". Worked great for @ a month. Then same problem. I drove it back to the shop, in reverse, and decided to try forward. What do ya know. Operating fine!!

Any advice would be much appreciated, because both myself and my 30+ yr supervisor are both stumped.

Thanks in advance.
  • Posted 16 Nov 2017 00:54
  • Discussion started by DieselJeep
  • Ohio, United States
Showing items 1 - 2 of 2 results.
If truck has any accessories like back up lites, alarms, etc, Try disconnecting them to see if trans operating properly. Has a machine do same thing because of taillights. Current from brake light circuit was bleeding to back up light which would partially energize reverse solenoid.
  • Posted 1 Dec 2017 01:24
  • Reply by Bacon123
  • Pennsylvania, United States
What pressures are you seeing? Maybe put a gauge set tied into the main, fwd and rev and see what the variation is between the different problems.
  • Posted 16 Nov 2017 10:22
  • Reply by BillG
  • Wisconsin, United States

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