RDU Issue at Low Speed …?

[Azusateach]

I haven’t posted here simply because I haven’t felt the need. However, my 23 OBX (with 11k miles) is currently in the shop and I need some of your collective thoughts.

I took my car in for its regular oil change and they found that I needed a new water pump. I’d been watching the fluid level and hadn’t seen anything so I’m glad they caught it before I had issues. But I’m wary now that I’m going to be one of the. many who seem to go through pumps every 10k miles.

That’s the first issue …

When I dropped the car off for the oil change I mentioned that there’s a “shudder” at LOW speed — 10-13mph — LOW RPM and LOW gear. I live in a community with a 15mph speed limit and so I‘m always driving slowly to get in and out of the neighborhood. Initially I was told that there’s a known issue but at higher speeds and gears which isn’t what I’m experiencing.

Has anyone else experienced this kind of shuddering, and if so, what was the cause? I’m supposed to be picking up the car today, but would like to tell them that they need to check again. I’m going to push to have their transmission tech take a drive with me so he can see what I’m talking about.

Thanks.

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[Ford Motor Company]

I haven’t posted here simply because I haven’t felt the need. However, my 23 OBX (with 11k miles) is currently in the shop and I need some of your collective thoughts.

I took my car in for its regular oil change and they found that I needed a new water pump. I’d been watching the fluid level and hadn’t seen anything so I’m glad they caught it before I had issues. But I’m wary now that I’m going to be one of the. many who seem to go through pumps every 10k miles.

That’s the first issue …

When I dropped the car off for the oil change I mentioned that there’s a “shudder” at LOW speed — 10-13mph — LOW RPM and LOW gear. I live in a community with a 15mph speed limit and so I‘m always driving slowly to get in and out of the neighborhood. Initially I was told that there’s a known issue but at higher speeds and gears which isn’t what I’m experiencing.

Has anyone else experienced this kind of shuddering, and if so, what was the cause? I’m supposed to be picking up the car today, but would like to tell them that they need to check again. I’m going to push to have their transmission tech take a drive with me so he can see what I’m talking about.

Thanks.

Hey there. I can look into your water pump and shuddering issues on my end if you'd like! To get started, can you please send over a message with your VIN and the name/location of the Ford dealer you are currently working with?

 

[Azusateach]

I’ve just sent you a message, hoping you’ll see it and let me know what I should do before I pick up my car later this morning.

Thanks.

 

[V8 Yankee]

Welcome to the RDU replacement club. Mine went out at 39K, the shudder issue is a common theme here. If you do a search you'll find many threads on it. Have the tech next to you while you duplicate the shudder. There will be no problem getting it fixed while under warranty but it takes time to order the parts. In my case the dealer replaced the left axle as well so there might be other issue's. Your dealer might try and do a drain and fill first or they might say its a vent hose issue or both. In the end it'll shudder as before. Count on a week or two of it being in the shop and push for a rental. If your dealer pushes back call Ford to get authorization, that's what I did. Good luck.

 

[Fordfan]

Welcome to the RDU replacement club. Mine went out at 39K, the shudder issue is a common theme here. If you do a search you'll find many threads on it. Have the tech next to you while you duplicate the shudder. There will be no problem getting it fixed while under warranty but it takes time to order the parts. In my case the dealer replaced the left axle as well so there might be other issue's. Your dealer might try and do a drain and fill first or they might say its a vent hose issue or both. In the end it'll shudder as before. Count on a week or two of it being in the shop and push for a rental. If your dealer pushes back call Ford to get authorization, that's what I did. Good luck.

Mine had the water pump issue and shortly after the rear end shudder/thumping. Fluid and vent hose replaced and noise still there. Goes back in tomorrow and suspect they’ll change the diff now. Have ext warranty and am getting a free rental

 

[Azusateach]

Update from the dealer:

I took a drive with the Service Manager and was able to replicate the shudder 3 times for him to feel. His initial comment was that it was as if the car was shifting to a higher gear and therefore the motor was lagging — kind of like what happens when you drive a stick shift and didn’t downshift when you should. He said that he’d take it back and “run a code“ on it to see if there was anything that shows up.

A couple of hours later I got a phone call and was told that the service manager and shop foreman both looked at the car and they came to the conclusion that the car is functioning normally. As I understand it, when the car’s running at low speed it “defaults” to eco mode, putting it into a 2-cylinder mode, which causes the shudder. If I drive it in normal or eco mode it will do that, but not in sport mode. Go figure … ?

At this point I’ve still got 4+ years and about 50k miles before my drive train warranty is up, so if something comes up they’ll deal with it then. It’s not unsafe to drive but I don’t like the fact that I’ve got a car that’s now had water pump issues and doesn’t drive smoothly at all speeds. I had thought that this would be my last car but I’m beginning to rethink that.

 

[Stircrazy]

what are you calling a shudder? I know mine at very low speeds isn't smoth, and it kind lugs like being in to low of a gear, which I figure is exactly what it is doing, it shouldn't go into 2 cyl mode at thoes speeds.

 

[curtcady]

Update from the dealer:

I took a drive with the Service Manager and was able to replicate the shudder 3 times for him to feel. His initial comment was that it was as if the car was shifting to a higher gear and therefore the motor was lagging — kind of like what happens when you drive a stick shift and didn’t downshift when you should. He said that he’d take it back and “run a code“ on it to see if there was anything that shows up.

A couple of hours later I got a phone call and was told that the service manager and shop foreman both looked at the car and they came to the conclusion that the car is functioning normally. As I understand it, when the car’s running at low speed it “defaults” to eco mode, putting it into a 2-cylinder mode, which causes the shudder. If I drive it in normal or eco mode it will do that, but not in sport mode. Go figure … ?

At this point I’ve still got 4+ years and about 50k miles before my drive train warranty is up, so if something comes up they’ll deal with it then. It’s not unsafe to drive but I don’t like the fact that I’ve got a car that’s now had water pump issues and doesn’t drive smoothly at all speeds. I had thought that this would be my last car but I’m beginning to rethink that.

We recently took our '21 OBX with 56k miles in specifically to investigate this, and our dealer came to the same conclusion as well. They also identified a faulty water pump (hadn't noticed any leakage) and replaced it.

Forums like this are an awesome source of data from customers. Knowledge is power!

 

[Azusateach]

what are you calling a shudder? I know mine at very low speeds isn't smoth, and it kind lugs like being in to low of a gear, which I figure is exactly what it is doing, it shouldn't go into 2 cyl mode at thoes speeds.

It’s hard to explain. The only other thing I can liken it to is how brakes will sometimes shudder, but it’s not as pronounced as that. But yes, it definitely feels like it’s in the wrong gear, causing the motor to lug.

The bottom line is that it’s been identified, acknowledged and it can’t be fixed. As I’ve said to the Ford Motor guy who initially responded, in the 40+ years I’ve been driving I’ve never, EVER had a car that did this, so I‘m having a really hard time believing that it’s normal.

 

[laurent1784]

My 2022 BB does something similar when I am on eco mode. Is if drive to slow and with a high gear, it will shudder when under no load. Just switch back to normal mode and give it some gas and your are good to go. It happens because of cylinder deactivation. The RDU shudder is something different. There are two TSB for that. One that states when turning full left or right you feel a shudder and it's because of fluid contamination. The other one elis related to Certain warning coming up, and has to do with a bath RDU motor.

 

[Azusateach]

My 2022 BB does something similar when I am on eco mode. Is if drive to slow and with a high gear, it will shudder when under no load. Just switch back to normal mode and give it some gas and your are good to go. It happens because of cylinder deactivation. The RDU shudder is something different. There are two TSB for that. One that states when turning full left or right you feel a shudder and it's because of fluid contamination. The other one elis related to Certain warning coming up, and has to do with a bath RDU motor.

Does the RDU shudder happen only at low speeds or all the time when you’re turning?

 

[Tonyf]

Hey there. I can look into your water pump and shuddering issues on my end if you'd like! To get started, can you please send over a message with your VIN and the name/location of the Ford dealer you are currently working with?

If it’s what I think you’re talking about , yes , I have the same problem on my 2021 Bronco Sport Big Bend whenever I drive below 30k/hr . Also my truck always sounds like it’s in sport mode . I just ignore it .

 

[laurent1784]

Does the RDU shudder happen only at low speeds or all the time when you’re turning?

The shudder happens mostly when you roll slowly from a complete stop and do a hard left or right turn. It is the disks that are binding that causes the shudder.

 

[Azusateach]

The shudder happens mostly when you roll slowly from a complete stop and do a hard left or right turn. It is the disks that are binding that causes the shudder.

Well. Guess I’ll be checking THAT today … ?

 

[curtcady]

Spent some time thinking about this today. If it IS "dropping to two cylinders" (into eco mode) it would be doing that all the time. This issue isn't something you can set your watch to. Wife just texted and mentioned the shuddering is still present and the bronco in general is running rough. Will be making another call to the dealer tomorrow.

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