42RLE torque converter clutch noise after service

[Tjbro]

Hey fellas,
I’ve got an issue I’m chasing. I recently had a failed solenoid pack, so I replaced it (new filter and fluid obviously). After reassembly I filled it with fresh fluid — Penrite ATF FS full synthetic multi-vehicle, as it’s listed as suitable for Chrysler ATF+4.
Since then I’ve been getting a chugging / shuddering noise that sounds like the torque converter clutch can’t maintain stable friction, especially at steady cruise. From what I can tell, the fluid is likely the issue.
I’ve now ordered Petronas ATF+4 to correct it. Just wanting to confirm I’m on the right track and see if anyone has any tips or advice — this is my first Jeep project.
Cheers.

 

[RS Hill]

When my solenoid went I used Valvoline ATF+4, non synthetic fluid. I didn’t experience any of the issues that you did. I think you’re on the right track with the fluid.

Hope you get it solved Sir.

 

[hear]

If you used only ATF+4 I would not expect the brand to give you any different results. I've used "name brand" and I've used Oreilly brand, walmart brand, and tons of it.

If you used anything other than pure ATF+4, I would love to hear feedback because I would expect problems. Multi-vehicle anything is a marketing way of saying "it looks like the thing you need but probably won't work in your car but we're happy to collect your money and there is a non-zero chance it will work if for no other reason than that the universe is non-deterministic at small enough scales and large enough energies. Who are we to say what will or won't work? Don't @ us."

 

[RS Hill]

If you used only ATF+4 I would not expect the brand to give you any different results. I've used "name brand" and I've used Oreilly brand, walmart brand, and tons of it.

If you used anything other than pure ATF+4, I would love to hear feedback because I would expect problems. Multi-vehicle anything is a marketing way of saying "it looks like the thing you need but probably won't work in your car but we're happy to collect your money and there is a non-zero chance it will work if for no other reason than that the universe is non-deterministic at small enough scales and large enough energies. Who are we to say what will or won't work? Don't @ us."

My consideration on this is the difference in synthetic fluids base stock ATF+4. Nothing more nothing less. I’ve had issues with transmissions prior when changing to synthetic oils vs standard base stock trans fluid. Some transmissions get an attitude lol

 

[Tjbro]

If you used only ATF+4 I would not expect the brand to give you any different results. I've used "name brand" and I've used Oreilly brand, walmart brand, and tons of it.

If you used anything other than pure ATF+4, I would love to hear feedback because I would expect problems. Multi-vehicle anything is a marketing way of saying "it looks like the thing you need but probably won't work in your car but we're happy to collect your money and there is a non-zero chance it will work if for no other reason than that the universe is non-deterministic at small enough scales and large enough energies. Who are we to say what will or won't work? Don't @ us."

Yes, that aligns with what I suspected. I used a multi-vehicle ATF because it explicitly states compatibility with Chrysler ATF+3 and ATF+4 specifications, so on paper it should have been acceptable. In Australia, genuine ATF+4 isn’t readily available off the shelf and usually has to be special-ordered.
That said, the 42RLE appears to be particularly sensitive to fluid characteristics, especially with torque-converter clutch operation. My hope is that replacing the fluid with a true ATF+4 via a pan drop and refill will allow it to dominate the remaining multi-vehicle fluid without needing a full flush. With some luck, that should resolve the TCC shudder.
I appreciate the guidance. Accurate information on this transmission is hard to come by locally in wa.

 

[Unique Username]

I doubt just changing the fluid will make any difference. ATF+4 is not going to break down as easy and will handle the day to day operation but a lesser AFT can make the transmission perform fine for a short time. I would suspect you have other issues and would consider you likely have other issues. Likely a failing PCM. Maybe hit up @Wranglerfix before tossing money at it. He would be the person who has a good understand of the operation on the 42RLE in terms of performance issues in operation.
ATF has done the job to move 42RLE down the road many of times when +4 was not available.

 

[Tjbro]

The only change after the transmission work was the use of a multi-vehicle ATF. Since the 42RLE seems to be a bit particular about fluid friction characteristics, especially with TCC operation, I’m going to swap back to a true ATF+4 as a starting point and see how it behaves.
I’m keeping the PCM possibility in mind, but they don’t usually fail in isolation without other symptoms. It seems sensible to rule out the simple variable first. The correct fluid should be here by the end of next week, and I’ll report back if the issue persists and reach out to the person you recommended. Appreciate the help.

I doubt just changing the fluid will make any difference. ATF+4 is not going to break down as easy and will handle the day to day operation but a lesser AFT can make the transmission perform fine for a short time. I would suspect you have other issues and would consider you likely have other issues. Likely a failing PCM. Maybe hit up @Wranglerfix before tossing money at it. He would be the person who has a good understand of the operation on the 42RLE in terms of performance issues in operation.
ATF has done the job to move 42RLE down the road many of times when +4 was not available.

.

 

[RS Hill]

As Unique User name says, the PCM is a possibility as well, that is some that escaped my mind.

The fluid side sometimes takes a bit to get the incorrect fluid out. If you had a drain plug, I would say do a couple drain and fills. Otherwise it’s the messy option by dropping the pan. No promises that this is the ticket but it seems closely tied from a time perspective.

I hope this get to the bottom of it for you.

 

[Tjbro]

As Unique User name says, the PCM is a possibility as well, that is some that escaped my mind.

The fluid side sometimes takes a bit to get the incorrect fluid out. If you had a drain plug, I would say do a couple drain and fills. Otherwise it’s the messy option by dropping the pan. No promises that this is the ticket but it seems closely tied from a time perspective.

I hope this get to the bottom of it for you.

Cheers. Once the ATF+4 arrives, I’ll swap it over and report back with the result at the end of the week.

 

[Tjbro]

Update: I’ve now received the correct ATF+4 and performed multiple pan drops to flush the system and dilute any remaining mixed fluid. The transmission is running noticeably cooler, which suggests the fluid side is now correct. However, the TCC shudder is still present. At this point, I’m leaning toward the torque converter clutch already being worn prior to the service, with old fluid contamination effectively acting as a friction crutch. The fresh ATF+4 has removed that compensation, so the TCC now has to operate on its true surface condition, making the slip/chatter audible. Given that the issue is isolated purely to TCC behaviour with no other shift or control anomalies, i think PCM involvement is unlikely. Im leaning towards replacing the torque converter. Any thoughts are appreciated thanks

 

[RS Hill]

Well, that’s a bummer. How many quarts did you refill after the drain? Sounds like there is bigger issue at hand.

Next thought is differentiating between a band issue or the torque converter shudder. When does this take place, is that at a shifting point or in top gear at steady throttle.

 

[Tjbro]

Well, that’s a bummer. How many quarts did you refill after the drain? Sounds like there is bigger issue at hand.

Next thought is differentiating between a band issue or the torque converter shudder. When does this take place, is that at a shifting point or in top gear at steady throttle.

Yeah big bummer.
I’ve done multiple pan drops, getting roughly 4.5 L out each time, and driven it between services over a few days to dilute the old fluid as much as practical without a full cooler flush. It’s now correct ATF+4.
Based on the behaviour, I’m leaning strongly toward TCC rather than anything band related. There are no shift faults at all, all gear changes are clean. The chatter is isolated to a steady cruise, fuel consumption is poor, and the noise immediately disappears with a slight throttle lift or when TCC is inhibited.
The fresh fluid has improved hydraulic efficiency and reduced temperature, but it hasn’t changed the symptom, which suggests the issue is friction side rather than control or hydraulic. Unfortunately that points to a worn or unstable tcc.
From what I’ve read, TCC failure is a fairly common issue on the 42RLE, so it’s looking like the transmission will need to come out . I’m now starting to look into whether there are upgraded or improved converter/TCC options available rather than refitting an OEM unit.

 

[hear]

Next thought is differentiating between a band issue

The 42RLE doesn't use any bands, just the 30RH & 32RH.

These friction materials are porous, I would not expect OP could ever flush enough, at least in a practical sense, all of the old fluid out. I would expect the clutches have plenty of residue & the TC as well. And if we assume that residual amounts are not going to be problematic, I'm pretty confident that just draining would not be enough to get you to a "dilution" that would get you close to optimal operation. Especially since a drain won't empty the converter and that's where OP believes the problem is. Short of doing surgery, I would probably do a full flush, where you suck in fresh ATF+4 from a new source and and then dump the old fluid before it gets back to the transmission. Be sure to flush the cooler as well.

But even then IDK. If it had been water you'd never get it all out, IDK if the wrong ATF will be similarly challenging.

 

[RS Hill]

Well that’s no good. As others have mentioned getting enough of the wrong fluid out might be very difficult.

In my thoughts if the transmission is down I say have the transmission rebuilt while it’s out as well as the converter replaced. Easy to say when I’m not paying for it but taking it out the second time for a misdiagnosis would only serve to make you mad and possibly contaminate the converter.

Personally I’d do both while you’re there. I did the same with my 42RLE in my LJ last year. My was slipping, nobody ever changed the fluid in mine by the smell and color.

 

[hear]

rebuilding is a hassle even if you're going to do it yourself, and this is coming from the guy who seeks out such jobs. I would almost certainly try the flush first. Replacing the torque converter is honestly 98% of the hassle. The rebuild job itself is pretty much a cakewalk, the effort is entirely in the unbuckling of the transmission.......which is exactly what you'd have to do to replace the TC. I don't envy your options.

 

[Tjbro]

rebuilding is a hassle even if you're going to do it yourself, and this is coming from the guy who seeks out such jobs. I would almost certainly try the flush first. Replacing the torque converter is honestly 98% of the hassle. The rebuild job itself is pretty much a cakewalk, the effort is entirely in the unbuckling of the transmission.......which is exactly what you'd have to do to replace the TC. I don't envy your options.

I’ve done plenty of transmission work over the years, so the job itself doesn’t worry me especially when it’s not buried in a slammed performance car.
I’m seriously considering picking up an AW4. Depending on its condition, I’d either rebuild it properly or do a thorough flush and fit a new TCC. The 42RLE just feels like pain wrapped in aluminium, whereas the AW4 is a much simpler unit, easier to live with, and ultimately far stronger and more reliable long term.

 

[hear]

I’ve done plenty of transmission work over the years, so the job itself doesn’t worry me especially when it’s not buried in a slammed performance car.
I’m seriously considering picking up an AW4. Depending on its condition, I’d either rebuild it properly or do a thorough flush and fit a new TCC. The 42RLE just feels like pain wrapped in aluminium, whereas the AW4 is a much simpler unit, easier to live with, and ultimately far stronger and more reliable long term.

You should look into what people have to say about that swap. It's basically a downgrade in every imaginable way, other than the cost of replacement, since AW4's are plentiful in the $200 price range. That alone might tell you something.