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my jeep grand cherokee 2001 limited 4.0/6cyl - mileage:129.000

the problem with transmission    
the 2nd gear slipt to 3rd immediately and it doesn't shift to 4th gear!
I change the solenoid without any success.
pls,tell me what to do?  

those transmissions are computer shifted... read the codes...


look at the data stream through a scan tool....    there are various sensors inside and outside the trans...

pick up an atsg techtrans manual for it...  that will help.. they are like 20 to 30 bucks...  

ya!
i forget to tell you about the codes!
the transmission has one sensor which is output speed sensor,and the code was P0720.
I checked the resistance for OSS and it was 567 ohm which is accepable "OK".
then i checked the harness and i fuond the cable shorted so,i change the wire from OSS to PCM, by this way i eliminate the fault code P0720 by checking it with scan tool!
Elimnating this code doesn't solve transmission trouble which is 2nd to 3rd gear upshift occurs immediatly "sliping" and no upshift from 3rd to 4th gear at all  
waiting your reply.
                            "thanks"  

Did you take any readings from the governor pressure solenoid? All shifts are controlled by the G.P.Solenoid and the transducer.  

I already change the G.P. & T.P. solenoieds with new one without any success!
I think my problem is that there is no power from P.C.M to the transmission.
I missed elecrical diagram for this part
any one can help !  

When you replaced the GP switch and the transducer you didn't take voltage readings at the solenoids? The voltage to the GP in park with key on should be 12 volts, at the transducer it should be 5 volts, and check for good ground( continuity )to the PCM.And the TCM.  

100% I'm agree with you and in parallel I'll test the O/D solenoid , switch and O/D circuit if there is a fuse blown or short/open.
But unfortunately i haven't the wiring diagram!

                                      "Thanks"  

post your email address and i will send you the wiring schematics.
Don't forget you also have what is called a TCM- transmission control module, should be locater rear if instrument panel , left of steering column.
You also have a TCR-transmission control relay, and fuse #5 a 30 amp fuse,this fuse powers the TCM and part of the PCM. they are both located in the power distribution center right front of engine compartment.  

First: I would like to thank you for your interest about my issue.
This is my e_mail: ja_grain@yahoo.com

second: I thought I have only PCM in my car which is located in the engine compartment,because other models has the both TCM & PCM in the engine compartment !
                          "Thank you in advance"