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Trans won't shift right after changing valve body and solenoid pack

9K views 11 replies 6 participants last post by  cdplayer 
#1 ·
I recently bought back a 1999 Limited 4.7. When I first sold it, it ran great. When I bought it back, the Jeep wouldn't move in any gear. It had codes P0731, P0732, P0733, P0734, and P1734. Not being extremely knowledgeable on how to troubleshoot, I dropped the pan and pulled the valve body/solenoid pack and replaced them with good used parts out of another '99 transmission. After buttoning it back up with new filters and fluid, it would now move but the trans often slipped when starting out and only shifted once instead of going through all of the gears. From reading other posts, I suspected I installed the filter seal wrong so I dropped the pan and replaced both filters with WIX filters, being sure to carefully tap the seal fully into place. I also replaced the speed sensors with the ones off the donor transmission. The problems with slipping and shifting still persist. Are there problems elsewhere in the transmission? The donor Jeep moved OK with the trans I used for parts (before the engine threw a rod). I'd love some expert advice before I pull the entire trans and tx case out. I'm 70 years old and while not afraid of work, it takes me a lot longer than it used to to get things done.
 
#7 ·
Valve body swap

Wondering if your old black plug solenoid pack was replaced with the newer designed white plug. If not you may just have swapped a bad solenoid pack for another.
If you did swap in a white plug solenoid pack, did you also install the updated
shift plate with it?
Picture attached shows the white plug solenoid pack on the left and the original black plug on the right.
The Q tip was used to point out for another member that the shift plate, among other changes, has a deeper well (seen at the tip of the Q tip).
Since the back up light switch is built into the solenoid pack, installing the white plug pack also brought back working back up lights. A nice plus!
 

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#8 ·
Now that I think about it since you installed a replacement solenoid pack. Did you torque it down to the correct specs and in the proper order. It also most sounds like the pack is not sealing to the valve body. Also did you make sure the accumulator plate was tight and that all the springs inside were not broken. Also over torqueing the solenoid is just as bad if not worse. Using a used pack could also be the problem with it not sealing correctly onto the valve body also over tighening it could have warped valve body. Just another idea.
 
#9 ·
I replaced it with a '99 unit (black plug). And I pulled the valve body and solenoid pack as a unit and replaced them as a unit. I didn't separate them from each other. I didn't drive the WJ that they came out of all that far but the trans was solid and didn't slip.
By the way, after I was done with the job, I erased all codes. The check engine light stayed on for some reason but when checking codes again there are no codes now.
 
#10 ·
I'm starting to wonder if the donor solenoid pack is defective. I only drove the WJ it came out of from the street to the driveway and back a few times. So I can't say if it was shifting properly then, just that I don't remember it slipping. What baffles me is that no codes show up now with my cheap Bluetooth code reader but the check engine light is still on. I read the initial 5 codes with this same code reader. Anyway, I don't want to invest in a new solenoid pack without being certain it is needed. Any thoughts?
I do have a complete 545rfe out of a 2001 WJ. I assume if I used part or all of it, I'd have to replace the TCM in my '99 or have it reprogrammed. Is this correct? I didn't think to save the TCM out of the '01.
 
#12 ·
White plug solenoid pack

White solenoid pack has been redesigned to resolve the shifting flaws the original black plug pack had.
One of which most WJ owners have experienced. No back up lights.
So if your WJ does not now have back up lights, installing the white plug pack will resolve that problem.
The back up switch is on the solenoid pack. The pin switch sticks over time.
It is highly recommended you acquire the shift plate(the one that goes with the newer design white plug pack) with the white plug pack.
If you try to use your old shift plate on the white plug pack, your shifting issues will continue.
 
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