Mercedes W5A580 transmission woes for Dave, Iguanaman and others

Throughout the WA580’s / W5A580’s life, readers warned that the transmission was extremely sensitive to fluid quality and would shudder badly when the torque converter clutch is applied with even a 0.5% water dose. The temporary fix was to flush the fluid thoroughly (Chrysler recommended a triple flush) and put in a new filter; the long-term fix was to apply RTV (form-a-gasket) to the base of the transmission fill tube to avoid future contamination (particularly on early models, made in 2003-2005), assuming that's where water got in. If the fill tube was incorrectly installed - that is, if the seal was not perfectly flush with the transmission housing, usually above it - then that must be fixed first, so it is completely flush. The procedure could take up to two hours and was covered in TSB 21-011-05 (it was covered by warranty at that time).
Another problem, at least through 2007, was the transmission filler tube o-ring leaking. Keith K. wrote that this was:
the “transmission cup plug adapter bushing.” The old ones had two white o-rings that were available separately; they all leaked and it looks like a pan gasket leak, there is a TSB from 2005 or 2006 about it. They superceded the O-rings to the whole bushing so you get a new plug bushing and O-rings, new black ones, already installed on it. The new design won’t leak.
Paul Knisely helped a reader whose W5A580 was making a vibration and low-frequency noise in drive, with the MDS activated between 18 and 50 mph. Four different dealerships had said that the system was working normally, and suggested driving in fourth gear to avoid overdrive. Paul checked the problem with Alldata and found a diagnosis that the clutch in the torque converter was not holding — showing it was, but not actually holding. This would cause the vibration.
For performance, “MoparMaven” reported hearing that one of the clutches in the WA580 transmission (not surprisingly) can't handle full power on the 4-5 shift from heavily modified engines (e.g. 700 horsepower and up). “Some clutch cannot take the rpm drop without mechanical advantage to break the tires loose, if only for an instant, because there was a declutching and reclutching. I’m guessing that the engine management system keeps the rpm from running away while this takes place... they recommend lifting for the 4-5 upshift.”
Some critics complained about the sometimes-heavy-handed torque management applied to keep the WA580 reliable, with the engine cutting power noticeably on shifts. Throughout the transmission’s life at Chrysler, critics also complained of its slow shifting. Still, as one forum poster wrote:
Chrysler may have overpaid for the NAG1 but it is hardly the slow shifting, unreliable transmission that the auto mags love to call it. Compared to a manual transmission, a human cannot shift faster than a NAG1. The NAG1 has powered some incredibly high horsepower LX vehicles with very little problems. Treat it badly and don't maintain it, and it will break like anything else. There are plenty of LX/Jeep owners who have ha absolutely no problems with the NAG1/WA580.
Early reviews of the transmission actually praised its relatively fast shifting, indicating that the “slow shift” issue may have come later, perhaps due to the torque management intended to prolong transmission life.
Chrysler WA580 5-speed automatic transmission flow video
https://www.youtube.com/watch?v=zQwN2-9mLME

Thats right !!! Good post Tom,it sure has a lot of valuable info.

very interesting. the autotrans is prolly the hardest thing to understand on a car!

My trans leaked last year...... o ring seal bad. Leaked over the winter in storage. Have extened warr. $100 is all i paid

Thanks for the post, Tom. I admit reading it makes my head hurt thinking about getting it fixed. Might be more inclined to run it into the ground, save up, and just get an SHR transmission if I'm going to keep the car a long time.

Iguanaman wrote:

Thanks for the post, Tom. I admit reading it makes my head hurt thinking about getting it fixed. Might be more inclined to run it into the ground, save up, and just get an SHR transmission if I'm going to keep the car a long time.

Maybe if you showed the dealer this article, they would just replace your nag1, as they should under warranty. If they refuse, I would contact Chrysler Corp. and file a complaint. If you persist long enough and often enough, they have to do something.

Illinois Chaos wrote:

Iguanaman wrote:

Thanks for the post, Tom. I admit reading it makes my head hurt thinking about getting it fixed. Might be more inclined to run it into the ground, save up, and just get an SHR transmission if I'm going to keep the car a long time.

Maybe if you showed the dealer this article, they would just replace your nag1, as they should under warranty. If they refuse, I would contact Chrysler Corp. and file a complaint. If you persist long enough and often enough, they have to do something.

I wish.

I told the extended warranty co. NOT to replace the trans before, because they were going to replace it with some trans out of a junk yard with close to my miles on it, and conventional wisdom was bad idea because you have no clue where that came from, sitting out rusting, etc.

Then when I contacted Chrysler engineering and opened a case, when I FINALLY got to talk to the case advisor, what came out of that was:

• They won't help me directly, I have to go through a dealer,
  
• They will not even LOOK at any info that isn't their own or from a dealer (I tried to steer them over to my LXF thread to see how many others were having similar issues),
  
• They contacted my dealership and the service manager told them I had aftermarket parts on the car (shaker and tips) so they were suspicious of my car anyways. (Yes, I know those have nothing to do with the issue).

JacksSRT8 wrote:

My trans leaked last year...... o ring seal bad. Leaked over the winter in storage. Have extened warr. $100 is all i paid

all I paid was $24 and within literally 2 mins it was replaced...It took me longer to jack the car and secure it on jackstands lol

HemiMag wrote:

JacksSRT8 wrote:

My trans leaked last year...... o ring seal bad. Leaked over the winter in storage. Have extened warr. $100 is all i paid

all I paid was $24 and within literally 2 mins it was replaced...It took me longer to jack the car and secure it on jackstands lol

lol, I remember that. Before I could ask you if you needed help you were done.

Just saw this thread on shudder. It seems the Europeans have been aware of it for some time now.

http://www.automaticchoice.com/new_parts.html

Illinois Chaos wrote:

Just saw this thread on shudder. It seems the Europeans have been aware of it for some time now.

http://www.automaticchoice.com/new_parts.html

that seems to be a completely different issue. i don't think i have heard of people having that problem. the early nag one problems are completely fluid contamination issues in the clutch packs and torque converter and the problems that result from that fluid contamination. (not miss diagnosed pressure regulator problems.)

hello all, just wondering if this could be the same issue or something completely different. i notice when i am driving and i start to break right around 20mph i can hear/feel it downshift hard. but only when it gets to about 20mph. nothing to bad but defintaly noticable. seems to be worse in the cold and when i am stuck in traffic and stop and go. any idea what it could be?

5.7daytona wrote:

hello all, just wondering if this could be the same issue or something completely different. i notice when i am driving and i start to break right around 20mph i can hear/feel it downshift hard. but only when it gets to about 20mph. nothing to bad but defintaly noticable. seems to be worse in the cold and when i am stuck in traffic and stop and go. any idea what it could be?

Mine used to do something similar to that. It would seem like the trans was having trouble figuring out which gear to be in when stuck in traffic.

Cool Joe thanks for the response. Hope all is going good for your house hunting. Since this only happens when I decelerate but not when I am accelerating is this something to worry abut or would getting a Diablo fix thus issue. Thanks

5.7daytona wrote:

Cool Joe thanks for the response. Hope all is going good for your house hunting. Since this only happens when I decelerate but not when I am accelerating is this something to worry abut or would getting a Diablo fix thus issue. Thanks

it could be something with the computer and its adaptive transmission. Perhaps, in an effort for better fuel economy, the computer "learns" your deceleration habits along with those of acceleration. So perhaps, when you reach 20mph or whatever, the computer is expecting to see brake pressure applied, and if you arent touching the pedal, the car engine brakes for you.... i too have noticed similar actions with my trans, but im just assuming thats what is happening.

All the above are symptoms I have had. Shuddering at low RPMs (around 25-40 mph cruising, usually under 2000rpm), the decelerating hard shift, all that.

Had a torque converter replaced, no improvement. Dealer checked another R/T in their used lot with around the same miles, same symptoms. They gave up.

Tom, I think the fix you found may be something to look into. Since my dad used to trade in the car when the ash tray was full, do we know anyone who could do the work that kit describes without killing me on labor?