Question about GMC Sierra 2500HD
Transmission model is AX4N.The reason that the car/trans only acts up after long drives is the heat.As metal components heat up,tolerances and clearances that were marginal or borderline before with moderate heat,become excessive clearances when really hot.More than likely there are internal transmission components with excessive wear.Many problematic areas inside the AX4N trans is the pump,where the oil pump driveshaft bearing wears out,the seal is torn,and hydraulic pressure falls off,common failure point in these units.The other areas are typical to all automatic transmissions,the clutch packs and bands wear and lose clearance.as well as some of the bushings inside the unit.I just rebuilt recently a trans exactly identical to your car,V8...4.6Ltr Lincoln,and it had minimal damage inside,but enough to throw the check engine light on with a Torque Convertor Clutch trouble code.The TCC was slipping excessively,and the vehicle computer recognized this,and illuminated the CEL.Chances are good that the damage inside your trans will be minimal,but now is the time to consider rebuilding it and restoring all the hydraulic circuits integrity,and resetting all the clutch pack and band clearances with new clutches,steels,and bands.A remanufactured torque convertor should also be installed along with rebuilding the trans.Be careful as to who does the work on the trans should you decide to rebuild it,as some people's definition of a rebuild doesn't quite qualify as anything more than a patch/repair job.A complete rebuild consists of tearing the trans completely down,loading it into a parts cleaner,and thoroughly cleaning it.From this point,the rebuild begins,including a banner overhaul kit,new steels,bands,seals,thrust washers as required,Electronic Pressure Control solenoid,all new bushings,set clutch pack clearances to factory specifications,along with setting unit endplay,and a remanufactured torque convertor.Good luck.
Posted on Dec 06, 2008
SOURCE: p0740 code on 2000 Honda Odyssey
Code p0740 is a problem in lock up control solenoid assembly, Check whether scan tool indicates another code. Does the scan tool indicate another code? YES - Perform the Troubleshooting Flowchart for the indicated Code(s). Do not continue with this troubleshooting until the causes of any other DTCs have been corrected. Measure the line pressure. Is the line pressure within the service limit? Repair the hydraulic system as necessary. Replace the Lock-up Control Solenoid Assembly set lock-up control solenoid valve/shift control solenoid valve A assembly and the A/T clutch pressure control solenoid valve A/B assembly. Turn the ignition switch OFF, and reset the PCM memory by removing the BACK UP fuse in the passenger's under-dash fuse/relay box for more than 10 seconds . Using the scan tool, check to be sure that the engine coolant temperature is 176°F (80°C) or above . Drive the vehicle at 55 mph (88 km/h) for more than one minute . Recheck for code P0740. Does the OBD II scan tool indicate code P0740? YES - Remove the torque converter and inspect for a missing torque converter O-ring. If the O-ring is damaged or missing, replace the transmission and torque converter. NO - The system is OK at this time.
Posted on Jun 11, 2009
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