Will doze for up to one hour ,then suddenly stop,no overheating but low pressure at speed clutch test port at rear of transmission.100 psi Priority valve pressure OK hot or cold,470-500 psi.i think there is pressure loss somewhere The whole drive train i overhauled early this year. Planetary,convertor,trans pump,resealed steering clutches and brakes. I renewed all undercarriage wearing parts back last year, can anyone help. Thanks
Any Diagnostic Codes showing ...?
Hi Nige This dozer details D5M LGP Serial Nr 3DR00331 Has only the basic warning, panel,NO E C M MODULE. There is a wiring harness connector rectangular near the fuse box,but the warning panel has been inoperative for long. I have CAT SIS INFO SYSTEM AND CAT DATA LINK COMMUNICATIONS ADAPTOR 11 PART Nr 275-5121,but no rectangular plug .If you need more info ?
If this is lever steer not finger tip steer check the park brake linkage for debris in it. Might not be closing the valve in brake off and leaking Priority pressure. Later Bob
Sorry, misread your post, if priority is staying up and P1 is low something is wrong in the pressure control pack of the trans valve. 100 psi is initial pressure and the valve is not modulating up to full pressure. Modulation is controlled by the orifice that controls the rate oil gets behind the load piston and compresses the springs to get full pressure. Later Bob
Hi Bob Re parking brake it has a fault,brakes stay off even if brake lever is up or down.Foot brake works normally,pressures ok. I have had the selector and pressure control valve out several times during sorting out this pressure problem.The last thing i did was fit a new Spool assembly relief behind the load piston.Shims in load piston ok total 3.25mm, Tested dozer again same problem.Priority valve normal pressure ,supply port rear cover low pressure 350 psi , P1 pressure 350 psi ,engine speed 850 rpm, cold oil. After one hour dozing Prority port 470 psi Supply port 110 psi P1 port 110 psi Engine rpm 2230 If more info needed let me know, j d a
I trust these pressures are the same in all gears? I think you should start with the brake valve, get the control of park brake right first. The oil flow from pump goes to brake and steering first and a brake oil leak will cause your trouble. Later Bob
Ok Bob Will work on brake valve first,check pressures again and get back to you again j d a
Hi Bob Have rectified park brake fault,linkage rods adjustment,pressures brake/steering clutch valve all correct.As per pressure charts in Cat SIS. Priority valve normal pressure,but supply and P1 ports at rear worse ? Gear in neutral ENGINE RPM - 850 850 2230 PRESSURES PSI - BRAKES ON. BRAKES OFF. BRAKES OFF. L H BRAKE 0 380 380 R H BRAKE 0 380 380 L H CLUTCH 310 310 385 R H CLUTCH 310 310 325 SUPPLY PORT 0 ? 110 ? 350 ? P 1 PORT 0 ? 110 ? 350 ? CONVERTER IN 30 30 120 CONVERTER OUT 40 40 90 Start up, oil cold J D A
Your problem is in the pressure control part of the trans control valve. Modulating relief valve is not functioning right. Later Bob
Ok Bob will look into the control valve again Thanks for the help J D A
Hi Bob Have checked the modulating relief valve orifice's also differential, ratio valve and small filter,all o k. The modulating relief valve was renewed a few weeks ago. Have tested dozer again twice the same result after one hour dozing. Priority. At 850 rpm - 410 psi .At 2030 rpm 510 psi. P 1 - - At 850 - 0 psi .At 2030 - 120 psi Transmission temperature normal. I am thinking if there is leakage somewhere in the Planetary,one of the clutch housings may be cracked and has not been detected at previous times transmission had been out and disassembled ? If you have more comments on this ongoing problem please let we know j d a.