I have a 96 tahoe (6 inch lift on 35's). When its cold the trans slips second to third until i let off the gas and the rpms come back down. When it does shift/grab its very smooth. Also (not sure if its related) My front diff does not engage. I did replace the sensor as well as solenoid on the front axle. Also swapped relay and fue which were in good condition. I have the typical 4x4 light blinks on switch. If my trans going bad as in bands or something, or could this all be related to a sensor? Thx
Trans 4x4 issues
- Thread starter thrashin
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Doubt it , SOunds like your Tourque converter maybe having problems locking up. Hows the trans fluid looking ?
Recently swapped trans pan and gasket. Fluid looked fine and magnet was clean.
Now has new pan,gasket, fluid, and filter. Same issue.
SunlitComet
OBS Jedi-Do Good
does engine respond well to throttle cracking when not in gear?
Engine response is perfect. Starts right up and runs like a top EXCEPT when cold the throttle does sometimes bounce slightly when sitting in gear holding the brake causing surges. Didnt think about that before. TPS? Can that have an affect on the trans shifting?
SunlitComet
OBS Jedi-Do Good
it can. but if it responds well and there are no codes i would not typically worry about it right now. but if you get surges in gear with brake depressed and you are not touching the gas pedal the iac could be acting up or a sensor may me giving false reading that the pcm would interpret as a throttle request by changing commanded iac position or injector pulse width. and yes that sensor could be the tps. if you had a way to test for its consistent smooth signal transition that would be great. hate to see people just throw parts at the problem. usually the tps malfuntion creates hard shifts and a soft or flaring 1-2 or 2-3 above part throttle is a sign that a tear-down inspection is in your future. at any rate because of the engine speed and tranny issues test you tps before doing anything else.
Throttle Position Sensor-3 The Throttle Position (TP) sensor is a potentiometer connected to the throttle shaft on the throttle body. By monitoring the voltage on the signal line, the VCM calculates throttle position. As the throttle valve angle is changed (accelerator pedal moved), the TP sensor signal also changes.
At a closed throttle position, the output of the TP sensor is low. As the throttle valve opens, the output increases so that at Wide Open Throttle (WOT) , the output voltage should be above 4 volt .
The VCM calculates fuel delivery based on throttle valve angle (driver demand). A broken or loose TP sensor may cause intermittent bursts of fuel from an injector and unstable idle because the VCM thinks the throttle is moving. A problem in the TP sensor 5 volt reference or signal circuits should set either a DTC P0122 or DTC P0123. A problem with the TP sensor ground circuit may set DTCs P0123 and P0117. Once a DTC is set, the VCM will use an artificial default value based on mass air flow for TP sensor and some vehicle performance will return. A high idle may result when either DTC P0122 or DTC P0123 is set.
Surges/Chuggles
Symptom Related Diagnostic Procedures
Throttle Position Sensor-3 The Throttle Position (TP) sensor is a potentiometer connected to the throttle shaft on the throttle body. By monitoring the voltage on the signal line, the VCM calculates throttle position. As the throttle valve angle is changed (accelerator pedal moved), the TP sensor signal also changes.
At a closed throttle position, the output of the TP sensor is low. As the throttle valve opens, the output increases so that at Wide Open Throttle (WOT) , the output voltage should be above 4 volt .
The VCM calculates fuel delivery based on throttle valve angle (driver demand). A broken or loose TP sensor may cause intermittent bursts of fuel from an injector and unstable idle because the VCM thinks the throttle is moving. A problem in the TP sensor 5 volt reference or signal circuits should set either a DTC P0122 or DTC P0123. A problem with the TP sensor ground circuit may set DTCs P0123 and P0117. Once a DTC is set, the VCM will use an artificial default value based on mass air flow for TP sensor and some vehicle performance will return. A high idle may result when either DTC P0122 or DTC P0123 is set.
Surges/Chuggles
Symptom Related Diagnostic Procedures
