P0700 and P0740 codes after WranglerFix PCM install

dtroth91

dtroth91

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As title states, experiencing p0700 p0740 codes after replacing the PCM with one from @Wranglerfix. 97000 miles

This did fix my hard shift from 1-2 that I was experiencing. Also fixed my occasional sluggish start from stop (feeling like I was in second gear).

Checked fluid few times and its full. (suppose it could be quarter to half a quart over).

Few months ago, to make a long story short, I dumped all my tranny fluid through one of the hoses leading to the radiator. It went into limp mode and i called the lady to pick me up and get some atf4 to refill it.
No problem, patch up the hose.

Then drove it 400 miles to Sacramento with no issues. Spent a few weeks there, and then on the way back approx. 175 miles or so i get a p0700 that i check with the key trick. I keep driving and it turns off shortly after and doesn't reappear until a few weeks after finishing the trip.

After developing (or noticing for the first time) some driveability issues I check the reader again and have a p0740 in addition to the p0700.

I did some of research and decided to just buy and replace the computer since messing with the transmission myself isn't quite feasible.

It fixed my driveability concerns, ie the hard shift and less than ideal start from stop.

I read p0740 is the TCC malfunction. I'm no expert on transmission but converter seems to lock up. However I suppose I am not sure if I am not noticing a slip or if I would know what the symptoms would be besides slipping.

The research I have done makes it seem like since the codes are still hanging around its likely the converter is on the way out.

I realize I will probably have to take it to a transmission shop to know for sure but, does it seem likely a rebuild is in the future?
 
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dtroth91 said:
As title states, experiencing p0700 p0740 codes after replacing the PCM with one from wrangler fix. 97000 miles

This did fix my hard shift from 1-2 that I was experiencing. Also fixed my occasional sluggish start from stop (feeling like I was in second gear).

Checked fluid few times and its full. (suppose it could be quarter to half a quart over).

Few months ago, to make a long story short, I dumped all my tranny fluid through one of the hoses leading to the radiator. It went into limp mode and i called the lady to pick me up and get some atf4 to refill it.
No problem, patch up the hose.

Then drove it 400 miles to Sacramento with no issues. Spent a few weeks there, and then on the way back approx. 175 miles or so i get a p0700 that i check with the key trick. I keep driving and it turns off shortly after and doesn't reappear until a few weeks after finishing the trip.

After developing (or noticing for the first time) some driveability issues I check the reader again and have a p0740 in addition to the p0700.

I did some of research and decided to just buy and replace the computer since messing with the transmission myself isn't quite feasible.

It fixed my driveability concerns, ie the hard shift and less than ideal start from stop.

I read p0740 is the TCC malfunction. I'm no expert on transmission but converter seems to lock up. However I suppose I am not sure if I am not noticing a slip or if I would know what the symptoms would be besides slipping.

The research I have done makes it seem like since the codes are still hanging around its likely the converter is on the way out.

I realize I will probably have to take it to a transmission shop to know for sure but, does it seem likely a rebuild is in the future?
Click to expand...


Did you figure it out? My LJ throwing the same codes
 
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The 0700 is a generic code saying something is awry on the transmission side of the vehicle.

0740 leads back to:


Wiring harness to transmission damaged, loose connection, open or shorted circuit

Torque converter clutch (TCC) solenoid

Transmission control module (TCM)

Enclosed are two common wiring failure photos on the 05/06 TJ’s.

I would recommend checking the black plug which controls the transmission. Spray the connector with contact cleaner (not dielectric grease.) Also, make sure the red connectors are snug. Some customers wind up zip tying the connectors due to play.

Please let me know what happens once you look over my suggestions.

Thanks,

Mark

3261743C-B617-4E44-914F-ECC72C9E9509.png


8813CC67-D543-4F82-B6DB-772E29DF07B9.jpeg
 
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Took it to a reputable transmission shop near me and they recommended that the torque converter be replaced and the transmission overhauled. Had it done a week ago and my CEL has gone away. Also definetly noticed improved drivability because the torque converter was functioning properly finally.
 
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If you will turn the overdrive off more or all the time I believe you you will extend the life of the transmission...I say that based on how badly the tall overdrive lugs it and shifts too much.
 
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AndyG said:
If you will turn the overdrive off more or all the time I believe you you will extend the life of the transmission...I say that based on how badly the tall overdrive lugs it and shifts too much.
Click to expand...
My LJ is regeared with 5.13s and 35s, so the OD works like it has stock tires. I'm beginning to suspect my torque converter isn't locking up and is causing the trans to overheat. We flushed and installed a cooler last week. I'm going to check the stuff Mark suggested and finish installing my temp gauge so I have a better idea of what's going on when I test drive. Also, when I dropped the pan there was very fine like smoothie fine metal shavings stuck to the magnet probably a quarter's size worth. What does that mean?
 
Can't speak to the metal shavings but I can say when I took it in to get overhauled it had thrown an additional over heating code, due to the transmission working harder on my commute. Can't remember the other code but I knew it was related to overheating/high temps


Sounds like an overhaul is in your future
 
minimull said:
My LJ is regeared with 5.13s and 35s, so the OD works like it has stock tires. I'm beginning to suspect my torque converter isn't locking up and is causing the trans to overheat. We flushed and installed a cooler last week. I'm going to check the stuff Mark suggested and finish installing my temp gauge so I have a better idea of what's going on when I test drive. Also, when I dropped the pan there was very fine like smoothie fine metal shavings stuck to the magnet probably a quarter's size worth. What does that mean?
Click to expand...
minimull said:
My LJ is regeared with 5.13s and 35s, so the OD works like it has stock tires.
Click to expand...
That means it’s terrible. I can’t fathom pulling a 35 with that Transmission’s overdrive with any gear ratio. No wonder you are having a lot of shavings. It’s eating itself up.
 
AndyG said:
That means it’s terrible. I can’t fathom pulling a 35 with that Transmission’s overdrive with any gear ratio. No wonder you are having a lot of shavings. It’s eating itself up.
Click to expand...
Pulling a 35? What are you talking about?
 
AndyG said:
I can’t tell what post I’m getting tire sizes from sir...I’ve worked 29 hours in two days and I probably don’t need to be on here.
Click to expand...
no problem, I was just confused as to what you were referring to. Hope you get some rest asap (y) that sounds like an exhausting schedule
 
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dtroth91 said:
Took it to a reputable transmission shop near me and they recommended that the torque converter be replaced and the transmission overhauled. Had it done a week ago and my CEL has gone away. Also definetly noticed improved drivability because the torque converter was functioning properly finally.
Click to expand...
I went through the same thing.
 
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minimull said:
100% that's why I wanted to understand what he meant. After reading through hundreds of threads trying to research in this forum, I know I should listen to AndyG.
Click to expand...
I’m just not a big fan of the overdrive in the 42RLE with any tire size...because any time a transmission is geared that way and shifts that much, it is going to generate a LOT of heat, and heat kills automatic transmissions. The slipping plates generate the heat and cook the fluid ....and as a general rule, the less any transmission shifts...manual or automatic, the happier it is internally.

The engine, the transmission and most other drivers are going to be happier with it off....I realize it puts you in the higher end of the engines’ peak rpm power, but that isn’t a bad place to be altogether.

The on by default setting was a bad call by FCA, and that is why @Jamison C and I persisted til we solved that ...it needs to be able to be only turned on intentionally as needed. We essentially found out how to reverse its’ function ...it is on the resources thread.
 
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AndyG said:
I’m just not a big fan of the overdrive in the 42RLE with any tire size...because any time a transmission is geared that way and shifts that much, it is going to generate a LOT of heat, and heat kills automatic transmissions. It burns the fluid up and that glazes the plates, and as a general rule, the less any transmission shifts...manual or automatic, the happier it is internally.

The engine, the transmission and most other drivers are going to be happier with it off....I realize it puts you in the higher end of the engines’ peak rpm power, but that isn’t a bad place to be altogether.

The on by default setting was a bad call by FCA, and that is why @Jamison C and I persisted til we solved that ...it needs to be able to be only turned on intentionally as needed. We essentially found out how to reverse its’ function ...it is on the resources thread.
Click to expand...
Thanks for the info. My LJ and TJ both came with an overdrive off switch from the factory. I'll start driving with it off unless I'm on the highway. I've already got the derale cooler to add to the TJ this weekend, but I wanted to wait on the LJ until we knew if the tranny was kaput, so I just added a little $50 hayden. When it gets replaced or rebuilt whether now or later, I'll add the derale to the LJ as well. I've only had the LJ since November and probably haven't even put 1k miles on it, so I was probably doomed from the start.
 
minimull said:
Thanks for the info. My LJ and TJ both came with an overdrive off switch from the factory. I'll start driving with it off unless I'm on the highway. I've already got the derale cooler to add to the TJ this weekend, but I wanted to wait on the LJ until we knew if the tranny was kaput, so I just added a little $50 hayden. When it gets replaced or rebuilt whether now or later, I'll add the derale to the LJ as well. I've only had the LJ since November and probably haven't even put 1k miles on it, so I was probably doomed from the start.
Click to expand...
I had a Diesel Ford van with an E40D transmission that had 440,000 plus miles , never rebuilt, and towed a lot of loads.

The key was dropping the pan and changing the fluid and filter, an aftermarket cooler, responsible driving, and using tow mode when needed (overdrive off).

Basically the transmission you have (and I have one) has such a high final drive it works like it is towing just to move the TJ around. It is in no way the right final drive even for stock tires and is light years away from the earlier 3 speed that would pull a 33” tire with stock gears.

It isn’t a terrible transmission, and it is on par with other similar electronically controlled transmissions. Even the E4OD by Ford, which is stout, has a 175,000 mile expected service life.
 
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