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Unread 03-17-2010, 02:34 PM   #1
06cherotect132
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HELP!!! PO750 Engine code WONT SHIFT FROM 3RD

I was driving down the road and heard a clunk. The jeep wouldn't shift from 3rd. I've been driving it like this for a day and i KNOW its not good for the tranny. I looked online and it said that i just drop the pan and replace the solenoid A which I'm not sure which one it is.

How easy is this job?
How much would it cost for a solenoid?
How much would a new pan cost? (there is a heavy leak)
What solenoid is solenoid a?
Any diagrams?

Thanks, I really appreciate it. I'm unemployed and looking for the least expensive fix. i'd hate to get rid of it, but if the repair is too high, i may have to...

Its a 2005 WK Hemi with 106k miles

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Unread 03-18-2010, 09:18 PM   #2
06cherotect132
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please any jeep experts on this one???
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Unread 04-09-2010, 08:58 PM   #3
gingerdenise77
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I actually had the same EXACT problem with my 2006 Jeep Grand Cherokee. First, I am a woman and so I hate to play into stereotypes but I really don't know ANYTHING about cars. Secondly, I am a single mom so I don't have any options other than taking it to a mechanic for help. I have attempted to get information online but haven't gotten any help yet. I had the problem with my Jeep about 2 1/2 weeks ago. I was driving about 25 mph, felt a small hesitation and then a few seconds later, the check engine light came on. I didnt hear anything strange from the engine or anything and was about 5 miles from home so I just continued my drive and just before arriving home, I realized instead of being in Drive, I was in 3rd. To make a long story short, my Jeep has been in a local garage for the past 2 weeks and they have supposedly checked everything that they can think of. They stated they have also spoken with Jeep specialists and to no avail. They changed the switch solenoid (spelling) and I was told during the test drive, it ran perfectly for about 10 to 15 miles and then dropped back into 3rd. I was told by someone in another Jeep forum to check the Input/Output Sensors ??? and I relayed the info back to the mechanic which they agreed could be a good idea to check. So, I purchased this part and after it was installed and during the test drive...the same exact thing happened. It seemed to drive perfectly for a few miles and then shifted back into 3rd. I just picked up my Jeep from the garage today and now have to take it to a Jeep dealership which I guess I should have done to start with but like I said, I am a single mom so I was just hoping that it would be something simple or at least minimal. Doesn't seem to be working out that way. I have no idea what it could be and wish that someone had some ideas.
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Unread 04-09-2010, 09:51 PM   #4
345jeep
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I think your Jeep transmission went into 'limp home mode' due to some kind of failure that it experienced. Tranny is computerized and and I don't know if you will be able to avoid having it properly diagnosed (realizing that there is cost to that).

In the meantime, you might want to disconnect the battery and connect it again to see if it will reset the computer and allow the tranny to resume normal shifting. Good luck (on employment and the Jeep)
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Unread 04-10-2010, 01:57 PM   #5
90grandoneer
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First, where are you folks taking your Jeeps for this maintenance? Second, when is the last time the fluid/filters have been changed? Have you checked the fluid level? What does the fluid look like...color? Should be red/pink. What does it smell like? Burnt smell? (If in doubt what it should smell like, go buy a quart of ATF+4 so you'll know in the future.) Also, you would have gotten DTC's if it had overheated. Has the PCM/TCM been flashed to the most current CALID's? There are some TSB's on the early units. What happens when you start with the shifter in 3rd and manually shift to 4th? Does it go, not go, shutter/chatter, or nothing? It could be the solenoid pack, or possibly clutches. I'd drop the pan and check for debris, specifically clutch material (usually looks like rag lint), aluminum, brass, or iron shavings. Watch the tech. and ask to see it as soon as they pull it. If everything is clean, no burnt fluid, fluid level was adequate, I'd go back and double check the solenoids and associated circuitry. Could also possibly be the TCM itself. Let's hope not, (mega $$$) as it is part of the PCM for this transmission. Also, just for info. sake, bare in mind that third gear in the 545RFE is basically "high" gear. Fourth and Fifth gears are overdrive gears. Limp mode puts it in 2nd or 3rd gear depending on the issue. Are you absolutely sure they changed the solenoid(s)? Did you ask to see the old one(s). Since everything had been working fine for many miles, it's pretty uncommon to have wiring harness problems, unless it has been tampered with or damaged in some way. Keep us posted on the progress. Ask to see, and take all changed parts (they're still yours), and have them give you a detailed explanation of what/why they're doing each particular action. Don't let them be parts replacers without accurate troubleshooting diagnosis. In other words, none of this, "I think it's this, or it might be that, so let's change it and see." Be wary if they "hem haw" around or are not willing to give you a complete explanation. Transmissions are a big mystery to most folks, and you're pretty much at the tech's mercy unless you have some understanding of how they work. The 545RFE has been around for quite a while and is a fairly reliable (although not the smoothest shifting) transmission. They normally do not completely fail without some of the above evidence showing up. Solenoids are more common.

Here's the shop manual's explanation of DTC P0750:

When Monitored:
Initially at power-up, then every 10 seconds thereafter. The solenoid circuits will also be tested immediately after a gear ratio or pressure switch error is detected.


Set Condition:

After three consecutive solenoid continuity test failures, or one failure if test is run in response to a gear ratio or pressure switch error.


Note: This DTC is strictly an electrical fault and does not apply to any internal

transmission failures.
Possible Causes
RELATED TCM POWER INPUT DTCS PRESENT
(T20) LR SOLENOID CONTROL CIRCUIT SHORT TO OTHER CIRCUITS
(T20) LR SOLENOID CONTROL CIRCUIT OPEN
(T20) LR SOLENOID CONTROL CIRCUIT SHORT TO GROUND
TRANSMISSION SOLENOID/TRS ASSEMBLY
POWERTRAIN CONTROL MODULE
Always perform the 45RFE/545RFE Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to
21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
Theory of Operation
The Transmission Control System uses six electronically controlled solenoids that allow hydraulic fluid to be applied to various friction elements (clutches), which enables the gear requested. The continuity of each solenoid circuit is periodically tested. Each inactive solenoid is turned on for a few milliseconds, then off. Each active solenoid is turned off for a few milliseconds, then on. This pulsing of voltage to the solenoid causes an inductive spike which can be sensed by the Transmission Control System. If an inductive spike is not sensed by the Transmission Control System during the continuity check, it is tested again. If the test fails three consecutive times, the appropriate Diagnostic Trouble Code (DTC) is set. If the solenoid test is run in response to a gear ratio or pressure switch error, one failure will result in setting the appropriate DTC.


Note: This DTC is strictly an electrical fault and does not apply
to any internal transmission failures.


Last edited by 90grandoneer; 04-10-2010 at 02:51 PM..
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Unread 04-10-2010, 02:50 PM   #6
90grandoneer
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Sorry, I just re-read "06chero's" post. If you've bashed the pan and it is leaking, I'd stop driving it until you can get it fixed. The solenoid is a "pack" with all six solenoids integral, as well as the transmission range sensor (TRS). It is mounted on the valvebody. You have to remove the valve body to get to it. If you're not checked out on this sort of thing, I'd take it to someone that is knowledgeable. You may be able to find a pan at a local wrecking yard (doubtful though), or maybe a local tranmission shop. Otherwise it's a dealer item.

Ginger, which engine do you have in your 06 Jeep? How many miles on it? Depending, you may have a different transmission, but most of the preliminary checks will be the same or similar.
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Unread 04-10-2010, 11:07 PM   #7
06cherotect132
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they fixed it with the changin of a transmission solenoid assembly... i bought the part, thought i could do, it but not enough room to get under the truck, even with jakcs and ramps so yeah.... 520 dollares later its fixed, but now i have the Input output circuit too high P0073 and P0113, bot now both of those are gone, and now i have service 4wd system... i dont get it, but at least it shifts
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Unread 04-11-2010, 08:58 AM   #8
cmassey_2006
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Quote:
Originally Posted by 06cherotect132 View Post
now i have service 4wd system... i dont get it, but at least it shifts
That message could be erroneous and having the dealer flash your FDCM module with newer software could fix it. See this TSB:

http://wkjeeps.com/tsb/tsb_wk_2101406a.pdf
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Unread 04-11-2010, 04:37 PM   #9
90grandoneer
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So, where was the "heavy" leak coming from? Was the pan bashed, bent?
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Unread 01-03-2012, 07:21 AM   #10
GCoopII
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Just an update to this thread to add my my experience with the P0750 code along with 3rd grear limp mode:

Changed out the shift solenoid on Friday. All in all not really a bad job. If you can change your tranny fluid you can do this repair.


Quick outline of what I did: (refer to your FSM for complete steps and Torques)
  • Like others have said -- After the pan is dropped the primary filter comes off.
  • Once the primary filter is off (Secondary filter can stay in place) there are literally 6 hex scres holding the valve body in place.
  • Before removeing the last two center screws holding the valve body in place be sure to unplug the harness from the tranny. I had to drop the front driveshaft where it connects to the transfer case to access the plug. Probably not necissary if you are familiar with how the plug works but I didnt want to break anything...
  • Remove the last two screws holding the valve body in place and carefully drop it down and out.
  • Once out, remove the old shift solenoid. Something like 15 torx screws holding it in place.
  • Install the new solenoid and put everything back together.
  • Refill with fluid.
That is really it. I got a brand new OE solenoid off ebay for 190 shipped. 327 new @ dealer. The fluid was another $65. I reused the existing filters because I had just changed the tranny fluid less that 5 thousand miles ago. New filters are around 50 IIRC. So for 250 dollars I did what the dealer was going to charge 900 - 1000 for. Really a no brainer.

It is still to early to tell if this has indeed cured my limp mode P0750 issue but I can say that the tranny is shifting better. After 50 or so miles I havent had any rough shifts like what would precede the CEL and limp mode before. I will update after a little more time has past.


Hope this helps.

-Gary
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Unread 01-10-2012, 07:51 AM   #11
GCooperII
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Quote:
Originally Posted by GCoopII View Post
Just an update to this thread to add my my experience with the P0750 code along with 3rd grear limp mode:

Changed out the shift solenoid on Friday. All in all not really a bad job. If you can change your tranny fluid you can do this repair.


Quick outline of what I did: (refer to your FSM for complete steps and Torques)
  • Like others have said -- After the pan is dropped the primary filter comes off.
  • Once the primary filter is off (Secondary filter can stay in place) there are literally 6 hex scres holding the valve body in place.
  • Before removeing the last two center screws holding the valve body in place be sure to unplug the harness from the tranny. I had to drop the front driveshaft where it connects to the transfer case to access the plug. Probably not necissary if you are familiar with how the plug works but I didnt want to break anything...
  • Remove the last two screws holding the valve body in place and carefully drop it down and out.
  • Once out, remove the old shift solenoid. Something like 15 torx screws holding it in place.
  • Install the new solenoid and put everything back together.
  • Refill with fluid.
That is really it. I got a brand new OE solenoid off ebay for 190 shipped. 327 new @ dealer. The fluid was another $65. I reused the existing filters because I had just changed the tranny fluid less that 5 thousand miles ago. New filters are around 50 IIRC. So for 250 dollars I did what the dealer was going to charge 900 - 1000 for. Really a no brainer.

It is still to early to tell if this has indeed cured my limp mode P0750 issue but I can say that the tranny is shifting better. After 50 or so miles I havent had any rough shifts like what would precede the CEL and limp mode before. I will update after a little more time has past.


Hope this helps.

-Gary

Well it hasnt come back after a few hunderd miles so I say the new solenoid did the trick. Hope my experience helps someone else.
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Unread 12-28-2013, 01:23 PM   #12
four2score
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GCooper everything still running ok?
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Unread 02-03-2014, 07:52 AM   #13
NOFATCHIKS
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Quote:
Originally Posted by GCoopII View Post
Just an update to this thread to add my my experience with the P0750 code along with 3rd grear limp mode:

Changed out the shift solenoid on Friday. All in all not really a bad job. If you can change your tranny fluid you can do this repair.


Quick outline of what I did: (refer to your FSM for complete steps and Torques)
  • Like others have said -- After the pan is dropped the primary filter comes off.
  • Once the primary filter is off (Secondary filter can stay in place) there are literally 6 hex scres holding the valve body in place.
  • Before removeing the last two center screws holding the valve body in place be sure to unplug the harness from the tranny. I had to drop the front driveshaft where it connects to the transfer case to access the plug. Probably not necissary if you are familiar with how the plug works but I didnt want to break anything...
  • Remove the last two screws holding the valve body in place and carefully drop it down and out.
  • Once out, remove the old shift solenoid. Something like 15 torx screws holding it in place.
  • Install the new solenoid and put everything back together.
  • Refill with fluid.
That is really it. I got a brand new OE solenoid off ebay for 190 shipped. 327 new @ dealer. The fluid was another $65. I reused the existing filters because I had just changed the tranny fluid less that 5 thousand miles ago. New filters are around 50 IIRC. So for 250 dollars I did what the dealer was going to charge 900 - 1000 for. Really a no brainer.

It is still to early to tell if this has indeed cured my limp mode P0750 issue but I can say that the tranny is shifting better. After 50 or so miles I havent had any rough shifts like what would precede the CEL and limp mode before. I will update after a little more time has past.


Hope this helps.

-Gary
I had the same problem, 05 Grand Cherokee wouldn't shift out of 3rd gear with code PO750, Shift solenoid. Searched the forum here and read this post by GCOOPII and decided to make the attempt at replacing the shift solenoid myself.

Had to use my VIN # to find the correct one. $265.00. Followed GCOOPII simple instructions and the jeep is running awesome now.

I will add, the plug you will need to undo before you drop the valve body.
It is located on top of the trans, drivers side on other side of the shift linkage. I was able to access it without removing the front drive shaft (but it was very tight).
There is a grey handle on the plug that has to be pulled down to disengage and the valve body came out with little force.
Plugging it back in was the tricky part, I placed the center 2 hex bolts in a few threads so there was some up and down movement, positioned the plug into place with finger tips and gently used a long crow bar to pry the plug down while pushing up on the valve body (be careful not to damage the wires) I then pushed the grey handle up with a long screw driver. Finished bolting up the valve body and the trans pan, filled it with 6.5 liters of ATF+4 trans fluid through the trans dip stick hole and its running great now.

A big thank you goes out to GCOOPII for posting this on here it saved me a ton of money.

Thanks again Gary for your post it was a huge help
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