Codes P0736 and P0841, Transmission pump whine noise

Tiny
MALLYBOY
  • MEMBER
  • 2004 DODGE CARAVAN
  • 3.3L
  • V6
  • 2WD
  • AUTOMATIC
  • 98,765 MILES
This vehicle after driving a distance of 80km journey and I return home, next my brother drove out with the vehicle and the vehicle stopped, he towed it home and I inspected the vehicle. I first place it on a hoist and crank it, I engage reverse, and it drove small and stopped. I engage Drive and it drive and shifted to 3rd and I stopped it and removed it from hoist. The next morning, I cranked, while idling, I began to hear a noise on the transmission which I didn't hear the previous day. I engaged Reverse and the noise stopped, it delays like 2 to 5 minutes before it loads, then I depressed the brake pedal and it move Up to a pole and it stopped, and the noise started again. I raised it and it didn't move. I engaged drive, I noticed hard shift, it moves up to a pole and stopped. I raised it and it didn't move. I engaged to Park and the noise continues. Now I suspect that Transmission filter was blocked causing the Transmission pump to make the Whining noise because transmission fluid was not reaching the pump. I diagnosed and picked P0736: Reverse incorrect ratio and P0841: L/R Pressure switch sense circuit under Pending fault. I ignored it because when oil is not reaching the fluid pump and then to Valve body, the ECM will interpret it as a pressure fault on the switch/solenoid. Do you have any other idea what could be the problem?
Sunday, May 22nd, 2022 AT 3:03 AM

17 Replies

Tiny
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This could be a couple issues but first, how did you confirm this filter is blocked or you just suspect it is and have not checked it yet?

What I would do is start with the fluid level and condition. What does the fluid look like and smell like? If it is low, top it off and retest.

https://www.2carpros.com/articles/how-to-check-and-add-transmission-fluid

As for the next step after this, we need to actually test the pressure to find out if there is a restriction or the more likely issue that there is a pressure issue/pump issue, or a leak that is preventing the pump from building pressure.

You can rent a pressure gauge from the parts store but here is a diagram of the test ports.

I would get the pressure of each one in park, drive, and reverse and see what they are.
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Monday, May 23rd, 2022 AT 8:07 AM
Tiny
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What I would do is start with the fluid level and condition. What does the fluid look like and smell like? If it is low, top it off and retest.
I have checked the level and top up 1ltr, it also smells good like other days when the fluid was changed newly.
Remember if I start the vehicle first in the morning and engage reverse, it will move and stop, if I engage drive, it will move and stop. But I will first check the filter after which I will check the pump through transmission cooler hose by unplugging it and crank the vehicle, if oil did not gush out, I will conclude that the fluid pump is faulty.
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Tuesday, May 24th, 2022 AT 12:03 AM
Tiny
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Got it. If reverse engages when it is cold but not hot that is normally a cut seal or failed pump internally. When the fluid gets hot and thins out it can open up small cuts in different seals. It would be the pump if all gears are affected. If it is only reverse then there is most likely a cut seal in that circuit. Checking the pressure will tell us that so let us know what you find with this.

Thanks for the update.
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Tuesday, May 24th, 2022 AT 7:06 AM
Tiny
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Hello,

Thank you once again for your assistance.
I have checked the fluid pump by disconnecting the hose to cooler and I cranked and oil was coming out with pressure. At this time, the vehicle idles without that noise until the engine reaches normal operating temperature, I engage reverse and rev the vehicle, it moves small and stop and the noise starts again. I engaged drive and it move ooo until it stop, I also engage L and it didn't move. At this point it cannot drive forward or reverse. I diagnosed and detect P0736 and P0846, but I have never checked the filter and the condition of the fluid on the oil pan. What could be the cause of this noise?
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Sunday, May 29th, 2022 AT 1:44 AM
Tiny
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Sounds like this is a converter noise. Can you get a recording of the noise?

More than likely the stator inside the converter has broken and this is the noise you are hearing and the reason you are not getting much movement when in gear.
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Sunday, May 29th, 2022 AT 7:47 PM
Tiny
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I think I agree with you because there was an information I read on Google and I will like to share it.
Here is it: what does a failing transmission pump sound like?
It's why a worn or faulty pump makes a whining noise in all gears, including park and neutral. A restricted or clogged transmission filter makes the same whining noise as a faulty transmission pump. It's crucial when diagnosing a transmission pump or a torque converter.
I will drop the engine and replace the torque converter clutch. I want to ask, could this be the reason why the vehicle had been giving this code long ago p1775: solenoid switch valve latched in torque converter clutch position, causing the vehicle to drag at wide open throttle but if you press the throttle slightly, it will move and shift upward gears?
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Monday, May 30th, 2022 AT 12:14 AM
Tiny
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The short answer is yes to all of this. The P1775 leads you to check the P0841 first which you have as well.

So basically, we have an internal leak somewhere and if the converter is making noise, then that would be the likely cause.

As for the pump failing, yes that will normally whine in all gears and is worse when accelerating. A very common failure on this transmission but this sounds like a converter. When you go wide open or accelerate hard at highway speeds and it doesn't accelerate then this is usually due to the converter clutch slipping.

I attached all this info below.
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Monday, May 30th, 2022 AT 6:35 AM
Tiny
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Sounds like this is a converter noise. Can you get a recording of the noise?
Yes, I have gotten video recording of that sound and I attached it below.
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Saturday, June 11th, 2022 AT 4:55 PM
Tiny
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You are correct that it does sound like a converter. Does it get fast if you rev the engine while in park? If it does, then this could be a flex plate issue. When they crack, they sound just like that or even an engine knock.

If you look under the vehicle, there should be an inspection plate that you can remove and allow you to inspect the flex plate.
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Saturday, June 11th, 2022 AT 7:49 PM
Tiny
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If it does, then this could be a flex plate issue. No, it is not the flex plate (flywheel), if it is flex plate, the noise will be very loud, if you engage reverse or drive, the noise will stop but start in neutral or park, I still suspect transmission filter being blocked, I will check and get back to you.
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Sunday, June 12th, 2022 AT 1:04 AM
Tiny
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Okay. Sounds good. Thanks for the update.

However, it may be worth checking the flex plate before you get too far because I was just burned by one a couple weeks ago that was doing something similar. However, you are correct that they normally don't stop when put in gear.

Let us know what you find.

Thanks
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Sunday, June 12th, 2022 AT 11:11 AM
Tiny
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I was just burned by one a couple weeks ago!
I want to understand you by asking question.
1. When you engage reverse or drive while the noise is making, does it move at all?
2. What effect can a broken Fles Plate due to transmission?
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Thursday, June 16th, 2022 AT 9:34 AM
Tiny
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A broken flex plate will do a number of things. First and foremost, it will create a noise that sounds like an engine knock.

All the flex plate does is connect the crank shaft of the engine to the transmission torque converter. Then in most all cases this is used by the starter to turn the engine over since it is connected to the crank shaft.

So normally they crack and then you hear the noise when the different cylinders fire which makes it sound like an engine knock.

Also, it can cause vibrations. It doesn't have a direct effect on the transmission because all the transmission needs are for it to spin the converter and as long as it is doing this the pump will create the pressure to operate.
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Thursday, June 16th, 2022 AT 9:39 AM
Tiny
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I still put it to you that it is between fluid filter, fluid pump and converter.
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Thursday, June 16th, 2022 AT 9:46 AM
Tiny
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Okay. Trust yourself. You are there looking at it and I am only reading what you are telling me so I would go with what you feel.
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Thursday, June 16th, 2022 AT 9:58 AM
Tiny
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Finally, I replaced the filter and the noise stopped and the vehicle has been driving fine under A/C for two days now.
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Sunday, June 19th, 2022 AT 8:36 PM
Tiny
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That is great. So, if the filter caused it to stop then it was restricting fluid flow causing the pump to whine.

Great job, and glad that solved it.
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Monday, June 20th, 2022 AT 11:28 AM

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