xzirri

Transmission (?) issues when cold

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I've had issues with low power combined with a weird noise and an RPM that won't go past 2K for a few seconds until I suddenly get the power back and the noise goes away. If I let the RPM drop to below 2K, this process repeats itself. This only happens when the car is cold though. When it's had a few minutes to warm up, everything is fine and I get a decent power delivery from standstill.

I've attatched a video, where you can hear the noise I'm talking about at 7 seconds, 13 seconds (I pushed the kickdown button at 16 seconds). I've tried to find videos or descriptions matching my issues online but I've had no luck. I've even been to a transmission shop twice, and they couldn't find any issues with the transmission. However, by the time I got there, the transmission was within operating temperature.

I did a transmission Oil change 9000 km ago and the Oil is still fine, so at least I know that the Oil isn't burning up. No burnt toast smell either. I'm wondering whether this could be sticky solenoids, torque convertor drainback, or maybe something else. Also, does anyone know what could be making that awful sound I'm getting? I'm not even sure what word to use to describe that sound, sounds kinda like a pump being starved.

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I know automatic transmissions are complex things and that people here might not know what the issue might be. Does anyone at least know about a forum of some sorts for automatic gearboxes?

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To me it looks more like a lazy turbo, but once it spools up, it goes fine. That would also explain the power being delivered fine if you dont drop below 2k, meaning turbo is always spooled up. 

You drop it below, it shuts down.  That is all assuming your turbo kicks in at that rpm?

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Thanks for your reply! I would have though the exact same thing if I had a turbo, but it's the 2.0 petrol, which does not have a turbo.

Today I also noticed that if I got up to 2.5k RPM on half throttle and then fully opened the throttle, the RPM would drop to below 2k with the lack of power and weird noise. I'm wondering if this could be either the pressure for the 1st and 2nd gear valves not being high enough for some reason, dropping it to 3rd gear, or that the torque converter clutch somehow engages when it isn't supposed to while cold... Any input would be appreciated!

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And the car revs fine in neutral?

There are no symptoms suggesting issue is on engine side, not transmission?

How about reverse, same symptoms?

Switch your car computer to show you current consumption, and when it starts to bog down, does the consumption to increase, and to which numbers?

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Car revs fine in neutral, no issues. Nothing wrong with the engine, as far as I can tell.

I have to say that I haven't tested this out in reverse. Thanks for the tip, that would actually help me narrowing down which parts of the transmission it could or could not be (if it is the transmission, that is)

Will have to test out these things tomorrow since the car isn't cold anymore as I have driven it today. Once again, thanks mate!

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I'm still inclined to think that it might be the engine who is at fault here. Have you changed the spark plugs recently, if ever?

Cleaned MAF sensor, put a new filter?

I know that those things would usually throw a code, but it's behaving so weirdly without any code, so anything is possible.

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I haven't cleaned the MAF sensor yet, nor changed the spark plugs. However, all filters except the fuel filter (since it's inside the tank) have been changed, yet the problem persists.

I'm skeptical to thinking it might be the spark plugs, as they either work or they don't. Even worn spark plugs don't hurt your performance more than maybe 1-3 % (as long as they don't misfire, which isn't the case here). I was planning on changing the spark plugs around next spring, as I've had a few expensive repairs done the last couple of months and I'm stretched thin at the moment.

Also, wouldn't a dirty MAF sensor cause issues regardless of whether the car is cold or within operating temperatures?

I also passed the MOT this week (after replacing a rear suspension arm) so there isn't any other issues with the car like increased emissions, which would be a typical issue with a dirty MAF sensor.

I'm worried that I might have to replace the solenoid packs, or maybe the entire transmission, as issues that disappear when the car is warmed up might mean some of the seals may have hardened. Weird thing is that I have done 14k miles without the issue getting any worse, and 6k miles after an ATF and filter change. The fluid still looks new.

I understand why you think it might be the engine and not the transmission, and I've been considering the same myself, but no mechanic has found any issue with my engine, apart from a water pump that I replaced about a year ago.

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You know what? I think I owe you an appology, because you might have been right about it being an issue with the engine and not the transmission. I stumbled upon this post:

This is basically exactly the same issue as I'm facing. He even describes the weird sound I'm getting a few posts further down. It doesn't seem like they came to a solution in that thread, but at least I have a starting point now!

If anyone knows anything about this particular issue I'd be happy for inputs!

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I'd try to write the guy a message. I see he has not been around for some time, but maybe he will get it in the mail.

This is just a guess, but have you checked the intake manifold? Maybe the problem is in air delivery, or flappers inside the manifold are somehow obstructing the air intake, but get cleared, or more open when warm?

 

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No, I haven't done anything major yet. Do you mean removing the intake manifold? Will I need new gaskets?

I'll try messaging him. I'm also thinking about cleaning the PCV valve, as the last post in that thread mentioned that as a possible solution. Would MAF cleaner work for cleaning that valve, and possibly also the intake manifold? I bought a can but haven't had time to clean the MAF yet.

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I do not know how good it will work on pcv valve, but since you will be taking it out, might as well give it a try.

I just mentioned intake manifold as a wild guess,  as the car might be struggling for air. As the intake flaps are on there, they could be restricting the airflow.

Do you have black smoke running out of exhaust?  This could indicate either running too lean, or starving for air. If the answer is no, i think we can drop the intake manifold thing.

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No black smoke, exhaust is normal. I guess I'll let the manifold stay on then 😜

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