Hello, We recently acquired a Caterpillar 955L. It moves in all gears, but as it starts moving, it loses power. We have performed the following checks and replacements: Inspected the transmission pump, and it does not seem to have any issues. Replaced the oil with new fluid. Changed all oil filters. Replaced some clutch pack discs. We are wondering if there is a specific point where we can measure the pressure with a gauge to rule out more potential issues. Next, we plan to check the seals on the clutch packs in the transmission. We don’t believe the problem is the torque converter because when we engage the gears (all shift correctly), the machine starts with power but then begins to lose strength to the point where even turning becomes difficult. It clearly lacks the necessary force to move the soil. Has anyone experienced a similar issue? Any ideas on what could be causing this problem?
I think the first thing you will require is a Service Manual. This will contain information on how systems operatre as well as how to test/adjust them. It will also have an Operation & Maintenance Manual with info on recommeded fluids and for all the periodic tasks to be performed. For a 13X-prefix machine the manual is Caterpillar Publication reference SENR7672. Although there are used paper copies up for sale on various internet marketplaces at this time the best value appears to be a genuine OEM manual in pdf format on a CD for $156 from HERE . Meantime attached is the transmission test & adjust from that service manual to get you going.
Is the engine bogging down?
You need to take pressure readings in and out on the same torque converter p1 and p2 pressures and main pressure did you clean the magnetic strainer
The condition of that strainer could give you valuable insights into the condition of the entire powertrain. Make sure you drain the oil before you pull the strainer otherwise you will get a soaking.