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Discussion Starter · #1 ·
68rfe the older comp transmission. When tranny temps reach 185-190 it starts shifting hard and at about 200, when your at a stop and pull out it holds first longer and shifts hard to 4th. Dont always throw a code but when it does its p0700 trans control sys mil request and p0871 trans fluid pressure sensor/switch C circuit range 1 performance. Any sugestions? When its normal temps, it shifts fine. This is not towing anything, just around town.
 

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Diesel Filled Veins!
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Sounds like you need a new pressure sensor. First I'd try cleaning the connections to the sensor and if it's still giving you issues to change the sensor. 1st to 4th gear change is your limp in mode because there is a problem. Hopefully Trans Engineer will chime in.
 

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Discussion Starter · #4 ·
I called and talked to there 68rfe tech. He told me the temps were normal and to lower them get a b&m cooler. He was real quick with me, not a big help. Has anybody had any similar problems with the pressure sensor?
 

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I called and talked to there 68rfe tech. He told me the temps were normal and to lower them get a b&m cooler. He was real quick with me, not a big help. Has anybody had any similar problems with the pressure sensor?
Temps are normal. Sounds like a sensor failure. Need a scan tool hooked up to monitor some readings. This will let you know if it is indeed a sensor.

South bound on my DROID.
 

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You are getting the behavior that the ECM/TCM command when there is a mismatch between shaft speeds the computers want to see and what they are seeing. In some cases bad clutches and in other cases low pressure. Could be valve body or pump or clutches. Did you have the codes in the TCM read? The P0700 code usually has more detailed codes stored at lower levels.
 

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TECH SPECIALIST
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The problem is likely the valve body. The P0871 code (that happens when trans gets warm) is very likely the 'ol worn SSV bore. So you probably need a new VB assy.

The worn SSV bore allows line pressure to leak into the OD clutch passage. The warmer the trans gets, the thinner the fluid is (and the more leakage you get). When you leak enough in there to trip the OD pressure switch (which happens at about 20 psi), you blow the P0871 (OD Pressure Switch Rationality) fault, which put you in full limp-in (4th gear only).
 
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