SES Code P0741 (Torque Converter) - I'm screwed..

[teklord69]

I don't usually cross-post from the other forums, but I would like to get more feedback on this issue.

Just as I thought the car runs flawlessly, cruising at 75-80 mph the other day, I felt the car suddenly "slipping" or quick hesistating at crusing speed. Ok fine so far..then another 3 minutes it happened again, and finally got the darn SES light (Service Engine Soon).

Got home did some research and it seemed like the symptoms is pointing to the TC (Torque converter)..I was hoping it isn't. Drove to PEP BOYS, they scanned the code for free and sure enough I got code P0741..F**K!

I have 88k on the car currently. Car is stock aside from Eibach springs and adtermarket wheels. The car runs fine..So far it is only during cruising speed is the issue. For example, when cruising at 80mph and I want to accelerate to 90..The car will go to 90 but it will slightly "slip" going there.

I am doing more research and readings into this and it seems like the TC is not locking up properly. I read the service bulletin on this and it seems like the solution is to replace the TC? Some questions I have:

- How common is this issue for people who have the 5-spd auto trans?
- Has this problem ever got resolved w/o replacing the TC ?
- How bad is it to continue driving the car with this condition?
- Has anyone DIY'd this problem with the TC ?
- If anyone had this professionally fixed, how much did it cost (dealer or Independent).

Update:

After spending the whole morning reading archives from here, Bimmerforums, and Roadfly, (searching code P0741) -I am now almost convinced that the problem is the seals of my Torque Converter. The tranny seems fine as it shifts in every gear and reverse perfectly. I can handle most issues with these cars but my biggest fear is anything to do with the tranny, partly because its almost always going to cost a lot of money and doing the work is not exactly a DIY.. Like the VANOS seals, the suspect is the seal material used in the TC. What puzzles me is that other cars with the same part and tranny can go way past 100K without the seals deteriorating.. Here is a picture from bimmerforums that shows the bad seal:


Since Audi uses the same tranny, I found this article that describes exacly what I am experiencing right now:

You are driving down the interstate on the way to visit an old friend. While you're listening to the radio and enjoying the open highway you suddenly feel something a little strange, perhaps like a slight engine surge. It does not happen again over the next half hour or so- you dismiss it as your imagination.

A little further along in your journey, you feel it again- this time it is accompanied by your check engine light illuminating. You feel a bit concerned, but the car isn't driving too badly, it just has this very occasional odd engine surge. Naturally, you decide to have it checked as soon as you get to where you are going. Here's what may be found...

As Audi's A4 and A6 models are starting to become a few years old, there are few problems that are being experienced with their transmissions. By far, the most common problem that is being seen at this point in time is an issue with the transmission's torque converter.

The problem typically starts with a check engine light coming on. While sometimes the actual drivability symptom is subtle, your vehicle's computer is able to detect it by comparing engine RPM with transmission input shaft RPM.

Often times, in addition to the light coming on, one will also notice an increase or fluctuation of RPM's at speeds above 45 miles per hour or so.

If access to a scan toll is available, either a VAG or Snap-on type with the correct European vehicle software, codes can be retrieved from the vehicle's computer in most cases.

Some of the codes that are normally found in the system include a code 18032 which is a MIL light request. This code simply means that the vehicle's computer has detected a problem and has illuminated the malfunction indicator light to let the driver know that something is amiss. This is a not so subtle warning to get the vehicle checked out.

The next two codes give a better indication of what the problem actually is. The first code that is often seen is a code 17125- torque converter clutch circuit performance. This code is set by the computer commanding converter clutch application but not seeing the appropriate drop in RPM that is associated with proper converter apply. Quite simply, the torque converter's clutch is slipping.

The second code that is usually observed is an OBD P0741- torque converter clutch stuck off. Similar to the previous code, excessive converter slippage is seen by the vehicle's computer. This code, however, usually results in the computer disabling the converter clutch's application altogether in an attempt to protect the transmission from further damage. All of this is usually going to require replacement of the torque converter.

Here's the nuts and bolts technical explanation of the root causes: ZF and Audi's original converter design utilized two rubber seals inside of the torque converter that were of questionable quality.

The two seals are responsible for sealing the hydraulic pressure that allows the torque converter clutch to engage and hold. One of the seals is a "lip" type that seals on the transmission input shaft and the other "o" ring type seal seals against the piston.

The material originally used was not up to the task when it came to dealing with the tremendous heat and pressure that occurs inside of a torque converter. Although Audi did release a second design input shaft lip seal, failures have been observed with those as well.

When the hydraulic pressure that is required to allow converter clutch application cannot be contained because of the faulty seals, the clutch will start to slip and usually destroy itself before too long.

When looking for a replacement converter to purchase from a remanufacturer, it is often helpful to ask them a few questions about their rebuilding procedures.

First off, you will want to find out if they are installing the latest design level seals as part of their torque converter rebuild- using original type seals will work for a while but will eventually lead to another premature failure. There now aftermarket replacements for these components that seem to be far superior to the factory parts.

Secondly, you will surely want to ask if the clutch itself is getting replaced. Believe it or not, this is not a given with some suppliers. The clutches in these particular units are of a multi-disk configuration. Replacing this entire multi disk set up is quite labor intensive and requires not only special tools but also a high level of skill- make sure your converter rebuilding company has both!

Naturally you will also want your rebuilder to replace any other components that normally wear out such as washers, bearings, one way clutches, and spline inserts. Most of the quality converter manufacturers will also pressure test and dynamically balance the unit once it is in the final stage of the rebuilding process.

Taking the time to find out that the job is getting done correctly is absolutely critical. As with any type of rebuilt or remanufactured automotive component, there can be varying levels of quality. With over 11 hours of labor involved in removing and reinstalling your A4 or A6's ZF5HP19 FLA transmission to replace the converter, it is surely a job that you will not want to do or have done more than once.

[RandallPhoto]

I haven't seen this issue tooo much in my time here (but I have seen it before) and you're right about some cars running perfect forever, then another car that's virtually exactly the same has problems like this creep up..

I have 176k miles on my car with a mostly original cooling setup and the transmission works perfectly. If you can get your hands on a rebuilt torque converter, it's shouldn't be toooo difficult to replace, but it will probably be time consuming. I've never dropped the trans out of my E39, but I've done it on other cars and expect it to take at least a solid weekend..

[rf900rkw]

Just to add to your searching misery, there are four totally different families of 5sp automatics in the E39 range. If this is about the car in your sig, then you have a 5HP19. In this family (the '19) BMW has two totally different torque converter designs, each in multiple stall configurations. So does Audi. In addition, the Audis have the converter cantilevered farther out, with a longer input shaft due to the differential. This seems to change the harmonics or something... Audi converters fail much more often than BMW.

But yeah, a 741 by itself is usually (say 90-95%) a torn turbine seal inside the converter. It does seem that the multi-disc 530s are more prone than the single disc 525s, but I don't know of anyone that has really kept score.

[delmarco]

I have some more intel.

How to diagnose your P0740 code to see if it is the Torque Convertor Clutch seals:

There is a method for testing if your ZF's P0740 error code is the Torque Converter (TC) Turbine Shaft seals. Get you car up to 80 mph on a flat stretch of road and your RPM should be at 'locked' 2750 rpms and not drifting to 2900 rpms. If it is 'slipping' then your rpms will be at 2900 or between 2750 and 2900.

This is how you lose the MPGs. :idea:

BMW says the only remedy is to replace the entire TC but people have replaced only the seals to clear the SES P0740 code and fix the slippage. :tsk:

SPECIAL NOTE regarding P0741:
People that replaced the TC or TC seals mainly did so because their TC failure was severe. In some of their cases the dreaded code p0741 occurred with P0740 which is worse than just getting the P0740 by itself. With a P0741 your gear cog warning lamp will be lit and your tranny may regress to limp mode and you will definitely feel something is wrong. At this stage the entire TC or tranny must be replaced. P0741 is very interesting and important to note because technically P0740 is thought of as a precursor to P0741 - as the TC condition worsens - but it doesn't seem to work that way. Most people that get P0741 always get it either simultaneously with P0740 or with one of the P073x (where x is 1 thru 4) codes or by itself with the gear cog warning lamp lit.


With SES P0740 by itself the car drives fine and people have safely driven their cars (normally) up to 60,000+ miles/5+ years and beyond with the SES P0740 continuously lit up and reported no issues at all other than slightly poor mpgs.

The reason behind this is P0740 slippage on the ZF is such that it occurs at extremely high speeds/driving condition. At slower sub 60 mph speeds the slippage is so slight that in may not even set off the SES.

This theory comes from the fact when the SES P0740 code is cleared the SES has been observed to only return after the car has been driven in conditions of high speeds or during continuous 60+ mph hwy driving.


Torque Converter Clutch Replacement
Most people reporting their TC replacements have either done it under some sort of warranty, done so with other service to the tranny or DIYed it at home/at a friend's shop-garage so the labor costs aren't clear for the P0740 but it should be somewhere between a tranny flush ($150) and full tranny replacement ($2500). By replacing the TC or seals you must also include the tranny fluid/filter/gasket service to the labor time/cost.

Based on the location of the shaft seals as seen in the ZF parts diagrams the Tranny and the TC both have to be dropped and/or removed to access the seals. Because of this the labor costs for replacing the seals is going to be high regardless of if you replace the entire Tranny, the TC or the seals.

Shaft seal BMW P/N 24121423529 priced $26.13 (pic #2)
TURBINE SHAFT O-RING 24121422247 priced $1.59 (pic #3)




The MOST IMPORTANT FACT I learned was the new reman/replacement TC and seals that the dealership sells are identical as the worn ones you are replacing and it has been proven to fail again after another 40,000 to 70,000 miles down the line. This is another reason people just live with the TC SES P0740 and drive the car until the tranny drops out.

What I plan to do:

I will do nothing for now. I ordered my PA Soft 1.4 and will clear the SES P0740 and just keep an eye on if it returns and how it returns.

I am also very curious on the labor for a TC replacement. The remanufactured TC part costs between $200 and $700 but the labor can be anywhere between $1,000 and $2,000. Which would be a waste if you are just replacing a defective TC with a newer soon to be defective TC that will fail 40,000-70,000 miles down the road. For the long term that leaves replacing the Tranny as the best and the most cost effective solution to clearing the TC SES P0740 code.

Thank you for the information! I figured the issue was a seal. What is your plan on fixing your transmission? How difficult do you think this would be to fix? I live in SoCal, so I could always go to that guys shop like you mentioned in your thread post.

[rf900rkw]

Your information is not very accurate.

Early GM units set a code P0740. This is a generic TCC system fault. Due to the primitive design, the system can not diagnose any deeper than that.

Later GM and all ZF in E39s do not set P0740. They have the smarts to narrow it down, and will set P0741 (slip) or P0743 (electrical failure)


Also, the dealer does not sell the torque converter seal. Nor does ZF. You have to go to a specialty manufacturer to get that seal. And replacing it requires cutting the torque converter open. replacing the seal, then welding the converter back together with less than .001" runout. Then balancing. This is out of the realm of the home mechanic, and almost every shop. The picture you show is of the pump seal and turbine oring for a GM. It has nothing to do with a P0741 in a ZF. Teh seal that fails in a ZF is deep inside the converter.

[cwelty]

I fixed the P0741 by replacing the torque converter with a rebuilt one. It seems that ZF used some defective seal material for a while. I bought rebuilt torque convertor from Eriksson Industries (authorized ZF distributor in USA). They convinced me that the seal they used to rebuild the torque convertor will not have same issue. I did this repair in November 2010 and everything is still fine.

My original thread is here:

http://forums.bimmerforums.com/forum....php?t=1566841

[kimokk]

Just to add to your searching misery, there are four totally different families of 5sp automatics in the E39 range. If this is about the car in your sig, then you have a 5HP19. In this family (the '19) BMW has two totally different torque converter designs, each in multiple stall configurations. So does Audi. In addition, the Audis have the converter cantilevered farther out, with a longer input shaft due to the differential. This seems to change the harmonics or something... Audi converters fail much more often than BMW.

But yeah, a 741 by itself is usually (say 90-95%) a torn turbine seal inside the converter. It does seem that the multi-disc 530s are more prone than the single disc 525s, but I don't know of anyone that has really kept score.

I have an '02 530i with the same SES P0741 code. If it was the torque converter turbine seal would there be signs of tranny fluid leaking out of the bell housing vent port? Or are there other signs besides pulling out the torque converter to confirm?

How do you know if its a solenoid or the module? Thanks.

[rf900rkw]

The 530 is the exact version that has the classic seal failure. The seal is internal., and separates apply pressure from release pressure. It does not seal pressure from the outside, so there will be no visible leak.

[o2sys]

2002 530i Auto here with same code, been driving over a year now.

I'm not going to do anything about it...its just a ticking time bomb for now.

[kimokk]

The 530 is the exact version that has the classic seal failure. The seal is internal., and separates apply pressure from release pressure. It does not seal pressure from the outside, so there will be no visible leak.

Thanks!

[Higgpigg]

Thank you,Randy

- - - Updated - - -

It's now 2017. How long we're you able to drive the car? What did you finally do?

[Higgpigg]

Randy are you still driving same car with no problems?