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code po740

Jlanesey, I drove the Jeep in 3rd for a couple of days and I got the Check Engine Light to go off! This morning I went into Smog and the tech failed it saying that he couldn't figure out what was going on... lol He said that the P0740 Trans Code is still on the computer, but the Check Engine Light is not on and when he returned the Jeep to me the CEL wasn't on. He thought I might have bypassed the light. He said he would pass the Jeep if I could get the codes stored on the computer resolved. I am picking up a TC tonight and will be replacing it over the weekend and going back for a re-test on Monday. He didn't charge me anything this time since he claimed it was his fault he went ahead with the test thinking there were no codes. How is it possible that the codes are still on the computer, but no CEL? The driving in 3 trick must only work for removing the CEL.
 
Did you clear the codes before you tried the driving in third trick? Have to do that so there are no codes stored in the computer.

The monitors take longer to set then I expected but I think you should have been in the clear.

I would invest in a scan tool that can read emmissions readiness monitors and the tcm. I don't think you would ever regret it, can use on tons of cars and really makes diagnosing problems easier.
 
No, I didn't clear the stored codes. I made the assumption that if the CEL light went off that meant that the monitor for the code was clear and then the stored code was clear. My bad...I am changing the TC tonight and tomorrow anyway. Hoping to retest Smog on Monday or Tuesday. I will have a scan tool available to me this weekend also. I will clear codes with the scanner after the TC replacement and then drive for a couple days to reset the monitors.
 
Yep, I know you said you said you already had trans out but the biggest tip I could give anyone is to remove the exhaust before it crosses over behind the oil pan, makes it so much easier
 
That's exactly where I unbolted the exhaust last time and it worked great. The thing that took me the longest (I am not kidding) was removing and installing the fluid filler tube. I honestly tried KY lube on the rubber o-ring and that couldn't even pop it in. Finally, after hours of frustration I put a jack-stand under the fill tube attachment on the pan for support and took out a section of cut 4x4 post and gave it a pop on the top and it went right in. Unbelievable.
 
Jlanesey said:
Did you clear the codes before you tried the driving in third trick? Have to do that so there are no codes stored in the computer.
Click to expand...
Exactly right!
Jlanesey said:
I would invest in a scan tool that can read emmissions readiness monitors and the tcm. I don't think you would ever regret it, can use on tons of cars and really makes diagnosing problems easier.
Click to expand...
I fully agree, it's the most-used diagnostic tool I have.
Jlanesey said:
The monitors take longer to set then I expected but I think you should have been in the clear.
Click to expand...
Once you learn how the tests work it is pretty simple to get all of them to pass in a short drive.

What works for me is the route to and from the freeway is about a mile and includes several signals, so I get to stop, idle, and start again, and by the time I get to the freeway the engine is almost fully warmed up. Then I drive at 55-65 mph for 4-5 minutes, turn around and drive 55-65 which takes about the same amount of time, and by the time I'm home all the tests have completed. All done in 13 miles!

Here's what I did today:

Code: 
1:22pm 133508 ignition on, engine off (and cold!) -- reset the scan codes
1:23pm 133508 Started engine and checked monitors. The following monitors
               had already completed their tests:
                  Misfire
                  Fuel System
                  Component
1:24pm 133508 Left Jeep idling while I opened the gate, then drove the Jeep out
              to the driveway where I left it idling, closed the gate, locked up the
              house, and drove to the freeway.
1:39pm 133511 On the freeway going 64mph -- man, the traffic and signals getting
              to the freeway were slow!
1:44pm 133515 At the undercrossing to turn around and go back.
1:44pm 133515 Turn off engine for 9 minutes and unplug scan tool -- doing some
              errands
1:53pm 133515 Start engine again, plug in scan tool and the following monitors
              have completed their tests:
                 Misfire
                 Fuel System
                 Component
                 Catalyst
                 O2 Sensor
14:03 133521 Turn off engine -- more errands
14:07 133521 Start engine, plug in scanner, and all monitors have completed their
             tests.

Total elapsed time: 43 minutes
Total distance: 13 miles
I suspect less time and mileage would have worked just as well, but I was doing errands to make good use of the time and mileage.
 
I think what takes me so long is the un-interupted cruising at 45+. Where I live is far from highway and hard to maintain that kind of speed.
 
So I had my transmission completely removed from the Jeep with the torque converter off in about 2 hrs. When I was just about to install the new TC I saw that it was missing the TC shaft bearing (separate part) so today I went to every part store in my town and the soonest I can get a replacement is Tuesday since mine is worn as you can see in the photo.



Immediately noticed that when I spin the inside shaft of my old TC it grinds like heck and apparently is supposed to have fluid in it. I didn't see much fluid. The new TC after I filled it with fluid is buttery smooth and noiseless when I rotate the inner shaft.

Does anybody have a quick pick or assembly procedure of how the fittings are assembled for the trans cooler lines that go into the transmission? This time when I pulled the lines out a small plastic cup and o-ring came out with both lines. Don't know what order these go back together.
 
Jlanesey, I installed a new bushing like the one pictured above, new front fluid seal, and new TC. Took it on a short test drive last night and instantly noticed near perfect shifting, scraping/grinding noises are drastically reduced almost to nothing, and there is no slight smell of burnt fluid anymore after driving. I have driven it for about a total of 25 minutes of time with about three ignition on/off cycles and I still had the same code present, but swung through a shop this morning and had them clear it and I am driving in 3 to make sure to get through Smog tomorrow. I wont know for sure if this problem is resolved until I do more driving and shift through all gears at higher speeds. Thanks for all your help!
 
Last night I had a good friend hook up a $4,000 Snap-On scanner and made sure all my codes were cleared from the computer and then I continued to drive the Jeep in 3rd (for certainty) right up to the point of the Smog station today. On my 4th attempt to Smog in about three weeks the Jeep PASSED! Afterwards I put the Jeep in OD and headed down the freeway to work at 60+ mph, so far no CEL. As of right now my conclusions are that the Jeep is running great and the computer checks out as cleared and ready.

Thanks Jlanesey for your help! I need to extend a special thank you to Kastein and Digger87 who were also a huge help in the early diagnosis and knowledge of the transmission. Much appreciated and I learned a ton!

With over 215,000 miles on my other XJ, yr 92 (photo below) I am thinking about rebuilding the transmission here in a similar fashion.

 
Hello I am having the same problem. The noise is pretty noticeable even in park. I just cleared the code and will drive it to get it ready for emissions. I do have a question. I was going to replace the torque converter like it was suggested here, but is that safe to do without a transmission rebuild? Is it safe to replace the converter by itself. I've been working on cars for a few years, but honestly the extent of my transmission knowledge is limited to R&R. Just want to make sure I'm not wasting time and money, or ruin a new converter by replacing just the converter.

BTW.... thank you all for all the information posted here.
 
PHP:
Code:
pimpollo41 said:
Hello I am having the same problem. The noise is pretty noticeable even in park. I just cleared the code and will drive it to get it ready for emissions. I do have a question. I was going to replace the torque converter like it was suggested here, but is that safe to do without a transmission rebuild? Is it safe to replace the converter by itself. I've been working on cars for a few years, but honestly the extent of my transmission knowledge is limited to R&R. Just want to make sure I'm not wasting time and money, or ruin a new converter by replacing just the converter.

BTW.... thank you all for all the information posted here.
Click to expand...
Probably should have mentioned mine is a 2001 RWD. And when hot, it sometims slips in reverse. I found a connector disconnected in the back of the transmission that I can't figure out where it goes
 
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