Unusual issue with WA580 box - P0741
 

Drove from Adelaide to Fraser to meet the family in Sunny coast last month for a 2 week holiday. Fun times with the Jeep and Family.

So just out of Tamworth going up and down the hills I notice my revs are definitely not matching my speed with the trans slipping from 80 kays and I get an error popping up on Engine Link advising me of the PID P0741 and I can see my Trans temps shooting up to 115 degrees. So I pull over to investigate.

Check the box and see there are some weeping around the return line of the cooler.
First thought is check the fluid, no dipstick so I make one out of zip ties and there is plenty of fluid and its clean and not burnt.
Car is still running to bring the temps down and I consider my options.

30 kay out of Gunnedah so if I can limp it I will otherwise I will get a flatbed from insurance.

Drive along the verge and can manage around 40-50klm's without too much slip so off I go. When I arrive I choose the local diesel service shop and he runs the scan gauge on it and gets around 30 codes coming back including the P0741. He also checks the fluids and says no problems.
There is one that stands out which is a Low Voltage so we check the battery and the optima is dead. Replaced it and cleared the codes, go for a drive and low and behold the code is gone. Actually all of them except for a Steering Angle sensor which I think was from when I replaced the steering box and I have a slight 2-3 degrees off center steering which throws the ABS light and no cruise.

So off I drive to Sunny coast, pick up the fam and drive back to Adelaide 2 weeks later. Problem solved.

Last weekend went to the Murray Mouth on Goolwa Beach had lunch and a bit of fishing with the kids then drove back home except when I get onto the freeway I am getting the same problem I had on the way up to Fraser and bang there is the code again.

So I get home and go over everything again. As well I decide to disconnect the throttle booster which I have been using for the last year. Take it in to get looked at and watch the temps and all good. They drive it and use the scanner to measure slippage and all good. Checked the fluid and again all good. He clears the codes I drive to work and then up the Adelaide hills and all good. No codes as of right now and stuffed if I can tell wtf is going on.

Yes the throttle booster is off but running it for a year and also the time in between codes I was driving from Rainbow Beach/Noose/Inskip so lots of sand driving.

Anyone else had the same code and not had to get the box replaced?

Hey Rollas

Just had an issue with a W5A580 in my WH Grand
Your code P0741, is not listed in any of my workshop manuals
The P074x codes refer to Torque Converter Clutch (TCC) slippage and pressure
The W5A580 have issues with their lock up clutches

First check for a worn or jamming pressure regulator valve in valve body
Secondly check for a sticky TCC solenoid (top right)
https://lh3.googleusercontent.com/me...wD_jvICCjkHWvA
Finally it might be the actual TCC itself, which would require a reco torque converter

Maybe try some snake oil additive for trannys first
Cheers,
ren0vator

So just an update on what has happened.

I have the Jk booked in for a service next week so will get the auto serviced again (new filter/oil) at the same time.

So far I have done over 700 km's since the issue came on.

No codes raised since with 200 km's of freeway driving at 100 km's.

Checked oil and again is bright red, no smell and if I was not having an issue would be fine.

I guess time will tell.

Ren0vator thanks for your advice and the links, I really hope I don't need them but if I do then I know who to call.

Will update the post if anything else happens which will probably be around Christmas when I tow the boat for 3 hours to Innes National Park from Adelaide.

Update so far.

Gearbox was flushed, new trans oil and filter and taken on test drive.
No slippage and temps still ok. Old oil had no contamination and was not burnt.

Added a Derale hyper cool oil cooler in line with the existing transmission cooler.

Temps are now when driving sitting on 75 degrees average, with some driving seeing a max so far of 80 with the trailer hooked up. Engine oil on the other hand is still climbing up to 95+ but the Coolant is able to maintain it and bring it down with the additional cooler now plumbed into the system. Coolant will sit around 5 degrees lower than oil.

85 - 90 degrees seems to be the operating temp for the Engine oil and 75 - 80 for the Transmission.

I am now getting an error of P2783 which is the Torque Converter Temp to high.

After discussions with the Trans specialist and Jeep its believed to be (and yet to do the flash) a software issue.

To do the flash means I have to redo my axle ratios/tyre sizes etc so waiting till I can go in an do it on the spot.

I am now about to install an oil cooler bypassing the OEM unit and removing it from the coolant which will again drop my temps. Issue is where to place the cooler as I have no more room at the front. I have ordered a new RH front guard and looking to add a vent and cooler in the kick panel area. Should be fun.

Just updating where it is now.

Still getting the P0741 error and can replicate it.

Any time I put the gearbox under load by towing the boat or going up a steep hill.

I can actually replicate it to the point of saying where it will happen going up a particularly steep hill.

Diesel use is fluctuating between 13 and 16l/100kms.


No overheating and still sitting at 75-80 but it does feel like the motor is pushing harder than it should in "certain" circumstances. Stop start city driving, under load towing and uphill.

There is a number of cases where the valve body has failed and there are a number of torque converter failures which could be as a result or a separate item all together.

I have a couple of choices here, drop the pan and replace the valve body and regulator and connection plug which are all seen as a cause of the issue. Or drop the box and put in a 2nd hand unit from a wrecked later model petrol or diesel. Cannot find any info to say they are interchangeable between petrol or diesel or if anyone has actually done it.

New valve body and all associated such as new fluid, filter is around $600 home job.

2nd hand trans is around $2500 plus new filter and fluid.

Sop what does the Ausjeep community think?

The transmission cooler does not run in the radiator on the CRD, the lower portion of the A/C condenser is actually the oil cooler.

You have most likely cooked the seals in the Convertor when you overheated it.
How many km’s ?



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I have 80K on it now, the issue was actually there before as well I just didn't get a complete shutdown only the code thrown.

I apologise, I should have said the OEM trans cooler in front of the radiator which you correctly pointed out is the lower portion of the A/C condenser.

So it could be the oil getting to 115 for a minute cooking the seals (I was watching the scan gauge as I was driving which is when it started to spike)

Wouldn't the oil then have had a burnt smell or discolouration? Which it did not have when we checked it or when the trans was serviced when I got back.