4l60 third gear problems
07-16-2015, 09:33 PM
#1
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4l60 third gear problems My car will not sift into third gear unless you have it floored from a dead stop
I've tried replacing the throttle position sensor and shift selenoids a and b, it had a old code p0122
I've tried replacing the throttle position sensor and shift selenoids a and b, it had a old code p0122
07-17-2015, 12:49 AM
#4
I'll throw out a guess that the 3-4 clutch pack is probably fried. There's a few different causes, but one of the most common is the 3-4 piston seal is worn out, letting hydraulic fluid blow past the seal. This prevents the 3-4 clutches from fully engaging and they basically rub together until the friction material wears downs to the metal.
Was the transmission fluid dirty looking the first time you dropped the pan? It should be bright pink and clear. Broken down friction material from a clutch pack will make the fluid look dirty.
Expect to need a rebuild if the clutch pack is worn out. The 3-4 clutch pack and the piston/seal would need to be replaced, and if you tear down the transmission you might as well do a rebuild and refresh.
Let bbond105, mrvedit, or one of the other experts opine too. I'm an amateur.
Was the transmission fluid dirty looking the first time you dropped the pan? It should be bright pink and clear. Broken down friction material from a clutch pack will make the fluid look dirty.
Expect to need a rebuild if the clutch pack is worn out. The 3-4 clutch pack and the piston/seal would need to be replaced, and if you tear down the transmission you might as well do a rebuild and refresh.
Let bbond105, mrvedit, or one of the other experts opine too. I'm an amateur.
07-20-2015, 08:49 PM
#5
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A more detailed and clearer description would let us help you more.
While a fried 3/4 clutch is the most common 4L60E problem here, that might not be the immediate problem here. When the 3/4 clutch shot, the trans will not shift into 3rd under WOT and the engine will hit the rev limiter instead.
Since you have to go WOT to get it to shift, I suspect low line pressure, possible due to a bad PCS (Pressure Control Solenoid, also called Force Motor) or other engine sensor (TPS, MAF, MAP).
Hooking up a trans pressure gauge is necessary to diagnose this further.
While a fried 3/4 clutch is the most common 4L60E problem here, that might not be the immediate problem here. When the 3/4 clutch shot, the trans will not shift into 3rd under WOT and the engine will hit the rev limiter instead.
Since you have to go WOT to get it to shift, I suspect low line pressure, possible due to a bad PCS (Pressure Control Solenoid, also called Force Motor) or other engine sensor (TPS, MAF, MAP).
Hooking up a trans pressure gauge is necessary to diagnose this further.
07-20-2015, 09:13 PM
#6
A more detailed and clearer description would let us help you more.
While a fried 3/4 clutch is the most common 4L60E problem here, that might not be the immediate problem here. When the 3/4 clutch shot, the trans will not shift into 3rd under WOT and the engine will hit the rev limiter instead.
Since you have to go WOT to get it to shift, I suspect low line pressure, possible due to a bad PCS (Pressure Control Solenoid, also called Force Motor) or other engine sensor (TPS, MAF, MAP).
Hooking up a trans pressure gauge is necessary to diagnose this further.
While a fried 3/4 clutch is the most common 4L60E problem here, that might not be the immediate problem here. When the 3/4 clutch shot, the trans will not shift into 3rd under WOT and the engine will hit the rev limiter instead.
Since you have to go WOT to get it to shift, I suspect low line pressure, possible due to a bad PCS (Pressure Control Solenoid, also called Force Motor) or other engine sensor (TPS, MAF, MAP).
Hooking up a trans pressure gauge is necessary to diagnose this further.
If a 3-4 clutch pack is bad, would the fluid pretty much always show signs of clutch material? I know my fluid was pretty nasty looking.
Of course, your suggestion to test the line pressure is always just about the best place to start when diagnosing a problem.