P0741 - Seriously...again?

[93SixtySpecial]

This actually isn't my Cadillac. But I have had plenty of Cadillacs with this code. 4 out of 6 Cadillacs I have owned have had this code. My father-in-law just bought a 2003 Deville with 90k on it a couple of weeks ago and they are now plagued with the code as well. Why didn't GM switch manufacturers of the solenoid if it was causing that much problems? Couldn't they have used a solenoid that actually worked from one of their other trannys? This is seriously an annoying issue and every transmission shop that I've talked to knows about the dreaded code and usually will tell you that nearly all Cadillacs will come in for that code.

Sorry for the rant, but I just think it's asinine that they couldn't figure out a decent solenoid.

This post does have a question though. Is there a "safe" year for Cadillacs between 2000-2005 where they changed the solenoid? Or are they all the same?

Also, what would you recommend for a suitable replacement solenoid? AC Delco? If it's apart, might as well put in the dangdest, bestest one out there so you don't have to do it again.

[CoupeDTS]

That was the reason I sold my precious 00 DTS

[Ranger]

It's not the solenoid. A solenoid will have P0741 & P1860. P0741 alone is a seal.

http://www.cadillacforums.com/forums/northstar-performance-technical-discussion/149834-information-p0741-p1860-1998-a.html

[93SixtySpecial]

Really? I thought it was the solenoid. So all of the Cadillacs that I've had fail are all seals? But in the bulletin it says there is more than likely a chuggle or surge. None of my Cadillacs have had that. Except for my current 99 Deville, but that's a completely different story.

[Ranger]

I too have the occasional P0741. Car runs just perfect. No chuggle or surging. I KNOW it is not the solenoid because I can feel the lock up at 41 MPH under a very light acceleration.

[Cadillac Jim]

I go by watching the tach and speedometer needles. When you let the car go to constant speed over 41 mph, the needles will fall into lock-step with no noticeable shifting feeling. But throttle pressure will accelerate the car with the needles staying in lock step; the tach will not waver with the gas pedal. If you press too hard, the TCC will drop out and you will get the torque converter again and that feels like a little downshift.

[KHE]

The P0741 code alone is caused by the torque converter exceeding the slip parameters set by the PCM. The slipage of the torque converter can be caused by worn seals in the TCC apply circuit. The trans. needs to be dropped and the seals replaced. Most shops will also replace the solenoid while the trans is out of the car.

[KevinW]

It is possible for transmission solenoids to fail intermittently, and this problem is not specific to any manufacturer. When current is applied to the coil, the resulting magnetic field moves the armature (steel plunger), which in turn redirects the flow of transmission fluid. Over time, fine magnetic particles accumulate in the area around the armature, causing it to bind at higher fluid temperatures due to thermal expansion. I suspect that strategic placement of high-strength magnets (neodymium) may help to prevent this mode of failure.

[93SixtySpecial]

I took his car for a spin last night trying to get the code to come up and I wanted to see if the TC was locking up. I went over a few hills going about 51 MPH and it seemed to be unlocking and locking. It didn't throw a light, but I did check the codes and the P0741 code was current, but no light. I'm assuming it detected a little bit of slip, but not enough to throw a light? So if one was to fix this, GM recommends replacing the TC solenoid, the input solenoid (what exactly is that), the TC, and input seals? Has anyone done this themselves? Has anyone taken it to a shop? If so, what did it cost?

[Cadillac Jim]

The shift solenoids can be changed by removing the oil pan cover and a valve body plate (it's not a job for the faint-hearted!) but this will fix most P0741 codes. If you get as deep as replacing the torque converter, you are really looking at a rebuild.

[KHE]

The shift solenoids can be changed by removing the oil pan cover and a valve body plate (it's not a job for the faint-hearted!) but this will fix most P0741 codes. If you get as deep as replacing the torque converter, you are really looking at a rebuild.

I think the shift solenoids you are referring to control the actual shifting of the trans from 1st through 4th gear. They are accessed bu removing the bottom oil pan and valve body. The solenoid that controls the torque converter clutch is behind the SIDE cover of the transmission.

If the torque converter is exceeding the slip parametersit will set the P0741 code. When only the P0741 code is set, it is most likely the seals in the apply circuit are worn out, allowing trans fluid to bypass the lockup circuitry. A Tech 2 scan tool can monitor the slip parameter with respect to the status of the apply solenoid.

[KevinW]

I took his car for a spin last night trying to get the code to come up and I wanted to see if the TC was locking up. I went over a few hills going about 51 MPH and it seemed to be unlocking and locking. It didn't throw a light, but I did check the codes and the P0741 code was current, but no light. I'm assuming it detected a little bit of slip, but not enough to throw a light?

The 2002 DeVille FSM notes the following in respect of MIL activation for P0741:

"The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met."

"The PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes."

[Ranger]

Kevin is correct. If P0741 is set it WILL illuminate the MIL. That code had to have been historical.

Has anyone taken it to a shop? If so, what did it cost?

If it was the solenoid alone, it is a $50 part, buried $2000 deep in the trans, but if you read the link I posted you'll see that it is more likely a seal and a new TC. Either way it is a big dollar repair. Ignore it and it'll cost you about 1 MPG. Much cheaper.

[93SixtySpecial]

I have had current P0741 CURRENT with numerous Caddys and it doesn't throw a MIL. I can take a picture/video of it if you want to see. I'm not sure why it's doing it, but I know for 100% that it's not history.

It's a lot more than 1 MPG. I know for sure from experience in comparing Cadillacs that have working TC and ones that don't. It can be around 3-4 MPG less or more. I'm not sure how long he is going to be keeping it, but it may be worth the fix.

[KevinW]

I have had current P0741 CURRENT with numerous Caddys and it doesn't throw a MIL. I can take a picture/video of it if you want to see. I'm not sure why it's doing it, but I know for 100% that it's not history.

A current P0741 suggests the DTC conditions for failure were met at one point during the previous or current 'trip', and no such failure has been detected (yet) in the current 'trip' if a failure event had occurred in the previous 'trip'. The MIL is triggered once a P0741 failure is detected during two consecutive 'trips', at which point it becomes a historical code. It is certainly possible to have a current P0741 and not observe the MIL if the failure is intermittent. Your observations are consistent with what is noted in the FSM, so there's no need for any video. BTW, I would not expect a seal to leak intermittently, but the DTC slippage threshold is proportional to the calculated torque output of the engine, and driving habits and conditions may vary day to day. If the latter variability can be ruled-out as a factor, I would lean towards a fouled solenoid - It wouldn't hurt to experiment with some high-strength magnets, as it is likely that the deposition is dynamic due to armature movement, and trapping roaming particles may eventually lead to a reduced accumulation in critical areas.

[Cadillac Jim]

I would fix the TCC solenoid if I drove the car on the road a lot, particularly if my driving included a lot of grades. The reason is that the TCC stops nearly all slippage during highway cruise and this makes the transmission run a whole lot cooler. As for the MPG, I never had the problem so I can't comment on that.

I've seen magnetic drain plugs for sale for oil pans for engines and transmissions forever. Back in the days when I drove a 235 CID Chevrolet six, I used a magnetic drain plug because that ancient design (finalized for the 1937 model year, with minor mods - aluminum pistions and hydraulic lifters in 1954 - until the next generation of inline six-cylinder engines replaced it in 1963) put the oil filter in the bypass line. It was *not* a full-flow oil filter. Thus a filling station doing an oil change could strip out the drain plug, "fix" it with a self-tapping drain plug without telling you, and bring the engine down. I even had shavings from this "fix" lock up the oil pump and strip the distributor gear on one engine.

I thought that this wasn't an issue anymore with the SBC V8s until the very same "fix" was applied to my 327 cid tricked-out Chevy Impala station wagon. About 1,000 miles after the oil change - at the dealer! - I heard a main bearing knock and took it in. Yes, my tri-metal high-performance main bearings were scored by shavings, and yes, the dealer replaced them with plain bearings, and yes, the dealer replaced my high-flow oil pump with a stock one. I put a magnetic drain plug in it and had the oil changed elsewhere after that.

In an attempt to prove to me that the self-tapping drain plug had left no shavings in the oil pan, the dealer tech had left the oil pan on the floor exactly as it had come off the engine. I came by on my lunch hour (I worked as a aerospace engineer in an office and was wearing a white shirt and tie) and was asked to look through the dirty oil for shavings. I rolled up my sleeve and picked up a pinch of shavings in the drain plug well and put them in his hand. The stunned tech folded them into a shop rag he was holding in his other hand and pretended that this had not happened. No, those weren't the only shavings I felt on the bottom of the pan; I picked up a long-and-curly one too, just for effect. I cleaned up and went back to work.

But, I digress. If a high-strength magnet has any effect whatsoever on your TCC solenoid, I would report it back here so we can all go to magnetic drain plugs on or 4T80E transmissions.

[Ranger]

I have had current P0741 CURRENT with numerous Caddys and it doesn't throw a MIL. I can take a picture/video of it if you want to see. I'm not sure why it's doing it, but I know for 100% that it's not history.

It's a lot more than 1 MPG. I know for sure from experience in comparing Cadillacs that have working TC and ones that don't. It can be around 3-4 MPG less or more. I'm not sure how long he is going to be keeping it, but it may be worth the fix.

The difference between a locked TC and an unlocked TC is only about 300 RPM. I could be wrong, but I would not expect that to result in a loss of 3-4 MPG. I'm still running at 22.5 (average), but mine is slipping a little due to the seal mentioned in the posted link as opposed to unlocked.

[KHE]

There already is a magnet in the bottom of the transmission oil pan. It is not very powerful but probably powerful enough. Every time I pull the pans on my cars, there is a silvery coating from the clutch material on the magnet.

[KevinW]

There already is a magnet in the bottom of the transmission oil pan. It is not very powerful but probably powerful enough. Every time I pull the pans on my cars, there is a silvery coating from the clutch material on the magnet.

That is correct. The 4T80-E has a 'common' magnet bonded to the pan; in the case of some older transmissions, like a 200-4R, they're removable, and usually become part of the mechanic's collection during service. I've observed a dark grey sludge-like substance on the ones I've cleaned. While they appear to be effective to some degree, the high strength magnets are capable of trapping a different class of particle. Add a couple neodymium magnets to the end of the dipstick and inspect them after driving 100+ miles.