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Discussion Starter · #1 ·
Hello guys, I got a 2005 Jeep grand Cherokee 3.7 L with 220,000 miles. For the past couple months it has been stuck in third gear and I’ve noticed I can shift it without pushing my brake pedal in and I change my brake light sensor. The last time I had a code checked it was saying something about a stuck A solenoid. And I’ve also changed the transmission speed sensor several times and nothing has worked I change the fluid and nothing I’m at a loss and stuck between a bad wiring issue or bad solenoids. Any help would be appreciated thank you
 

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Step 1 -
Use a scanner to access ALL codes, post them here someone will advise how to proceed.
 

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could you SHARE the codes?
 

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Try cleaning or changing the solenoids and conductor plate inside the valve body. Since this trans is used in lots of vehicles there are several Youtube videos on this process. Here is one:
 

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Discussion Starter · #6 ·
Here are my error codes as of right now.

P0752 - shift solenoid A stuck on.
P0753 - shift solenoid A electrical.
 

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can you confirm this is a NAG1 trans- we are assuming* so checking is advised.

p0753 is a circuit issue I would start there


*based on spec sheets
 

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Discussion Starter · #8 ·
can you confirm this is a NAG1 trans- we are assuming* so checking is advised.

p0753 is a circuit issue I would start there

*based on spec sheets
Yes, I already confirmed this with the dealer and I've already swapped out the speed sensor 4 times (the conductor plate) 3 of which were used. Two worked for a rough 2-3 months then quit. So I bought the 4th and final one from AutoZone for 260$ It didn't even attempt to work. That threw me off by a mile. Which brings me here.
 

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I would recommend carefully inspecting the transmission wiring and connectors for damage or corrosion. The wiring diagram provided by jtec should be helpful.

Do the transmission solenoids check out for resistance (ohms) and move when energized with 12 volts? I have seen the resistance specs somewhere so you should be able to search for them.
Edit: The resistance specs are included on the jtec diagram.
 

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Discussion Starter · #10 ·
I would recommend carefully inspecting the transmission wiring and connectors for damage or corrosion. The wiring diagram provided by jtec should be helpful.

Do the transmission solenoids check out for resistance (ohms) and move when energized with 12 volts? I have seen the resistance specs somewhere so you should be able to search for them.
Edit: The resistance specs are included on the jtec diagram.
Okay, I'm going to be doing my solenoid checks friday as the weather warms up.
 

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can you confirm this is a NAG1 trans- we are assuming* so checking is advised.

p0753 is a circuit issue I would start there

*based on spec sheets
FWIW, the 3.7l ONLY came paired with the NAG1 transmission.
 

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that is what the specs say, a confirmation is always suggested- gone down the wrong rabbit whole and learned. *** U ME
 

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Discussion Starter · #13 ·
Help fellas, changed my Speed sensor and still nothing good. Changed the solenoids and still the Jeep is in limp mode. I’m literally lost as to what this thing issue is.
 

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WHY are you spending money? :confused:

Did you even read the attachment I added - do any of the tests?

Is it above comfort level to check wiring?
 
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Discussion Starter · #15 ·
WHY are you spending money?


Did you even read the attachment I added - do any of the tests?

Is it above comfort level to check wiring?
I've had this part for a little while. The weather hasn't permitted changing this part. I'm going to be doing wire test. My solenoids also got replaced. So my assumption is, there's a wire issue or a PCM issue.
 

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I'm going to be doing wire test. My solenoids also got replaced. So my assumption is, there's a wire issue or a PCM issue.
FYI, your Jeep with the 3.7 engine, has a separate TCM located under the dash near the steering column. The PCM is located under the hood.
 

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We have experienced the P0753 (HISTORIC now) p0730 (historic), replaced solenoid 1/2,4/5; tested pins at harness and tcm, checked out. Put new conductor plate, transmission plug, fluid, filter,ran and then as driving had to put it in reverse, went into limp mode, and now pending P0752 code. Shut car off, measured fluid, was at 65 mil at 200 degrees, added fluid, at 75 mil now, ran, not in limp mode, no code. Don't trust it is fixed because seems erratic limp mode. Drives beautiful then gets stuck in first or second. Could it be tcm or pcm? The resistance on all solenoids checked out when we did conductor plate; resistance from harness to tcm checked out; plug never leaked, tcm was dry. Does computer need to relearn? Could historic faults be doing this erratic issue? Or does it take 4-5 drive cycles to learn? It's a nag1 in jeep cherokee. No metal in pan, seems like an electrical issue but chasing it. Advice welcome.
 

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AA thought - from my side notes the NAG1 trans pass thru connector is problematic bad electrical connections AND IIRC an updated connector - with all your time going into trans DID you change the connector maybe even sold with new plate?
 

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Hello,yes all new connector plug and conductor plate and shift solenoid A. We have methodically been going through process of elimination. Plug was always dry, no leaks. Resistance checked well. It is really becoming a mystery. Any way to directly test tcm and PCN? We tested p0753 circuits via the harness and tcm following schematics; also tested solenoids. Thanks.
 
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