Have had a long term problem with the steering clutches not fully releasing at lower rpm on my D6. I finally put together enough test gauges to check the pressure ports on the trans hydraulic system.
Some background:
* the steering clutches have had new seals on the release pistons
* replaced bevel gear bearings (since I had it apart)
* adjusted steering clutch valve linkage
* magnetic screen for pump checked/cleaned
* Torque converter screen checked/cleaned
* No heating problems with engine or torque converter
* Visually checked for leakage on steering clutch line where it Tees into top RH rear of trans - No visible oil leaking into trans case
* Disassembled trans pump to check condition - no visible wear, .003 side clearance on gears (No spec. given for clearance between top of gear teeth & housing? May have to check that)
1) Took pressure readings and found Pump pressure (Low Idle readings were low) & (High Idle readings a little high)
Torque Converter Inlet pressure was a little low (cold oil @ 55°F)
2) Adjusted High Idle pump pressure down to get it in spec.
Adjusted Converter Inlet pressure up to spec.
3) Re-checked pressures: Low Idle pressures well below spec.....High Idle pressures OK
See marked up pressure chart
Looks like either the pump is weak or something has an internal leak......
Would my Cat dealer have equipment to bench test the pump for pressure & flow?....or would it cost as much as replacing the pump?
Any Suggestions on how to proceed?
Sorry...Don't know why the .pdf is coming in so large.
Chart.pdf
Some background:
* the steering clutches have had new seals on the release pistons
* replaced bevel gear bearings (since I had it apart)
* adjusted steering clutch valve linkage
* magnetic screen for pump checked/cleaned
* Torque converter screen checked/cleaned
* No heating problems with engine or torque converter
* Visually checked for leakage on steering clutch line where it Tees into top RH rear of trans - No visible oil leaking into trans case
* Disassembled trans pump to check condition - no visible wear, .003 side clearance on gears (No spec. given for clearance between top of gear teeth & housing? May have to check that)
1) Took pressure readings and found Pump pressure (Low Idle readings were low) & (High Idle readings a little high)
Torque Converter Inlet pressure was a little low (cold oil @ 55°F)
2) Adjusted High Idle pump pressure down to get it in spec.
Adjusted Converter Inlet pressure up to spec.
3) Re-checked pressures: Low Idle pressures well below spec.....High Idle pressures OK
See marked up pressure chart
Looks like either the pump is weak or something has an internal leak......
Would my Cat dealer have equipment to bench test the pump for pressure & flow?....or would it cost as much as replacing the pump?
Any Suggestions on how to proceed?
Sorry...Don't know why the .pdf is coming in so large.
Chart.pdf
D6c Trans/steering clutch pressures (revisited)
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