Rear Differential Unit (RDU) Replacement

[ejgreco44]

the vent hose wasn't initially covered! I had to call the owner of the dealership and address my issues; I just purchased the vehicle in April and Im having all these issues already.

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[Slingy]

the vent hose wasn't initially covered! I had to call the owner of the dealership and address my issues; I just purchased the vehicle in April and Im having all these issues already.

How is it now that the vent hose is replaced? Did it resolve the problem or is it too soon to determine?

 

[Dude]

Just be aware the RDU Vent hose and the RDU fluid drain/refill is not a solution to RDU issues

Those 2 repairs are designed to delay and get you out of warranty so future RDU repairs / replacement would be at your expense ( if outside the factory warranty or if covered and outside the powertrain warranty unless you have some other warranty that will pay if the RDU or its components fails in the future )

If you are having RDU issues, arm yourself with information, Search for the following to see related owner posts:

25-2351
24-2386
24-2185
23-2335

https://www.broncosportforum.com/forum/search/1663971/?q=25-2351&o=date

https://www.broncosportforum.com/forum/search/1637783/?q=24-2386&o=date

https://www.broncosportforum.com/forum/search/1637775/?q=24-2185&o=date

https://www.broncosportforum.com/forum/search/1637778/?q=23-2335&o=date

 

[pres319]

Hey guys, I have a 2022 BS and I'm getting the grinding noise in the rear end. After reading all the posts I'm pretty sure its a RDU issue. How do I get the dealer to agree to replacing the RDU under the powertrain warranty? I have 55K miles so I need to do it soon.

 

[Dude]

Hey guys, I have a 2022 BS and I'm getting the grinding noise in the rear end. After reading all the posts I'm pretty sure its a RDU issue. How do I get the dealer to agree to replacing the RDU under the powertrain warranty? I have 55K miles so I need to do it soon.

Make an appointment with the dealership, when you arrive ask to have the service advisor and the tech in the car so they can drive and you can verbally demonstrate when the issue occurs

Bring a couple copies of TSB 25-2351 25 July 2025 (TSB 25-2351 supersedes TSB 24-2386 (which supersedes TSB 24-2185 which supersedes TSB 23-2335)

If you haven’t had the RDU vent hose installed and a drain and fill of the RDU fluid they are likely going to do that first which unfortunately is a stall tactic to get you past the warranty expiration

https://www.broncosportforum.com/forum/threads/new-tsb-25-2351-rdu-technical-service-bulletin-chatter-shudder-during-low-speed-turning-events.16807/post-265341

 

[Fernata]

Any advice before contacting Ford Corp??
Issue was first reported in August of 2023 and at that time they changed the differential fluid which also seemed to take care of the moaning noise when backing.
That issue took forever to resolve, but it is back now. Even got a case number from Ford Corp for this problem.
Now it is no longer under warranty, of course. So after changing dealerships, per Ford Corp, and them test driving and not being able to duplicate the turning issue along with the moaning. They said to wait until I needed to get new brake pads and would just have to deal with the moaning. I asked service manager to look into the turning issue.
It went in for inspection and oil change yesterday and I asked if he had looked into it. He did not, but I had printed out the Technical Service bulletin from link I got on forums about the RDU fix and handed it to him.
That's when he looked into and gave me a quote to replace RDU. He asked if I bought an extended warranty. lol
Any suggestions are appreciated other than him telling me to say how many fords I have owned when contacting ford. Sure, my first New Ford was a 1974 Ford Pinto.

 

[Dude]

Any advice before contacting Ford Corp??
Issue was first reported in August of 2023 and at that time they changed the differential fluid which also seemed to take care of the moaning noise when backing.
That issue took forever to resolve, but it is back now. Even got a case number from Ford Corp for this problem.
Now it is no longer under warranty, of course. So after changing dealerships, per Ford Corp, and them test driving and not being able to duplicate the turning issue along with the moaning. They said to wait until I needed to get new brake pads and would just have to deal with the moaning. I asked service manager to look into the turning issue.
It went in for inspection and oil change yesterday and I asked if he had looked into it. He did not, but I had printed out the Technical Service bulletin from link I got on forums about the RDU fix and handed it to him.
That's when he looked into and gave me a quote to replace RDU. He asked if I bought an extended warranty. lol
Any suggestions are appreciated other than him telling me to say how many fords I have owned when contacting ford. Sure, my first New Ford was a 1974 Ford Pinto.

If the RDU needs replacement you may be able to get Ford to split the cost with you
You didn’t state how many miles is on the vehicle but is worth a try to call Ford and negotiate a price (call Ford not the dealership)

As stated in prior posts - Ford installs the RDU Vent hose and replaces the RDU fluid as a stall technique to get your vehicle out of warranty

See this link and read through what other owners have done with their RDU issue

https://www.broncosportforum.com/forum/threads/rear-differential-unit-rdu-replacement.10712/post-262979

 

[Fernata]

OK, thanks. It has 69K on it. First reported at 35K.
Service manager said they may split some of the cost as I mentioned to him the same as to stalling til out of warranty. No, they wouldn't do that!
I will read the link you provided before I contact.
I'm just wondering if this issue was there all along when I first reported about the moaning way back in the first year of owning and if I should bring the Case# to their attention.
I had a print out of service done and much to my dismay, much of what I told them I was having issue with was Not stated on the print out. So, so much for a paper trail.
Thanks again

 

[Dude]

OK, thanks. It has 69K on it. First reported at 35K.
Service manager said they may split some of the cost as I mentioned to him the same as to stalling til out of warranty. No, they wouldn't do that!
I will read the link you provided before I contact.
I'm just wondering if this issue was there all along when I first reported about the moaning way back in the first year of owning and if I should bring the Case# to their attention.
I had a print out of service done and much to my dismay, much of what I told them I was having issue with was Not stated on the print out. So, so much for a paper trail.
Thanks again

Good luck!!

And if the moaning is coming when you back up it could be the rear brakes moaning issue
TSB 25-2051 Moan Noise In The Rear Brakes When Vehicle Is Driven In Reverse
TSB 25-2051
TSB 24-2348
TSB 24-2326
TSB 23-2308
TSB 23-2041
TSB 22-2326

 

[RSH]

The latest RDU TSB is TSB 25-2351. This is for single clutch RDU's, It's actually a repair procedure, it's not like the prior band aid fix vent hose/fluid change TSB.

 

[Dude]

The latest RDU TSB is TSB 25-2351. This is for single clutch RDU's, It's actually a repair procedure, it's not like the prior band aid fix vent hose/fluid change TSB.

Just adding the link to your post:

https://www.broncosportforum.com/forum/threads/new-tsb-25-2351-rdu-technical-service-bulletin-chatter-shudder-during-low-speed-turning-events.16807/

 

[Fernata]

From what the service manager said. there is a repair rather than replace, but parts are Not available for repair. He said price wasn't much different. I am good at reading upside down, but was small print, so unsure what the repair cost was.

 

[Agent084]

I’ve been experiencing the same issue recently in my ‘22 Badlands (just about to hit 50k miles). Was wondering a couple things for those of you who’ve had this done, I’ve got a size up tire from factory size on my Bronco (245/65 R17, 225/65 was stock, but I know they also made models with 235/65). Did your dealership give you issues with the tire size if you had larger tires going in? I’m willing to buy a cheap set “factory size” when I take it in if need be for this to be covered under my 100k mile drive terrain warranty, but was just curious best what the way to approach this would be. I already took it in once thinking it was the transmission, and of course the “didn’t find anything” and blamed it on the larger, all-terrain tires for the “rough ride”. After reading up on multiple threads, I’m leaning more toward the diff issue now specifically because of the common grinding at low speeds when making a sharp turn.

Would anyone have an advice how to get this fixed? It’s pretty infrequent now, should I wait till it’s more noticeable to take it back in? I just got my Bronco back last week so it hasn’t been long since I had em in the shop. Should I contact Ford directly, or go through the dealership first?

Any help is appreciate, thanks!

 

[Dude]

@Agent084 .. you would need to go to a dealership before contacting Ford (should that contact be even necessary since you have the 100k warranty)

smart idea to put on a set of ‘factory’ type tires and if you can take the RDU issue to a different dealership since one has already blamed an issue on larger tires

if you decide to take it in, arm yourself with the current TSB and read through the RDU posts from other owners; also suggest you go with the tech and service manager on a ride along so you can demonstrate the issue and they witness it - but is more complicated in your case since the issue is not always present

Your ‘22 might not have the updated RDU vent hose and RDU fluid change which is the first stall tactic a dealership might fix just to get you past your warranty so keep that in mind


Pic showing RDU vent hose is:
https://static.oemdtc.com/NHTSA-PDFs/MC-11010795-0001.pdf

There is also TSB 25-2351 RDU TECHNICAL SERVICE BULLETIN Chatter/Shudder During Low Speed Turning Events

https://www.broncosportforum.com/forum/threads/new-tsb-25-2351-rdu-technical-service-bulletin-chatter-shudder-during-low-speed-turning-events.16807/

This post provides a good place to start to read up on other owners posts

https://www.broncosportforum.com/forum/threads/rear-differential-unit-rdu-replacement.10712/post-262979

 

[Agent084]

@Agent084 .. you would need to go to a dealership before contacting Ford (should that contact be even necessary since you have the 100k warranty)

smart idea to put on a set of ‘factory’ type tires and if you can take the RDU issue to a different dealership since one has already blamed an issue on larger tires

if you decide to take it in, arm yourself with the current TSB and read through the RDU posts from other owners; also suggest you go with the tech and service manager on a ride along so you can demonstrate the issue and they witness it - but is more complicated in your case since the issue is not always present

Your ‘22 might not have the updated RDU vent hose and RDU fluid change which is the first stall tactic a dealership might fix just to get you past your warranty so keep that in mind


Pic showing RDU vent hose is:
https://static.oemdtc.com/NHTSA-PDFs/MC-11010795-0001.pdf

There is also TSB 25-2351 RDU TECHNICAL SERVICE BULLETIN Chatter/Shudder During Low Speed Turning Events

https://www.broncosportforum.com/forum/threads/new-tsb-25-2351-rdu-technical-service-bulletin-chatter-shudder-during-low-speed-turning-events.16807/

This post provides a good place to start to read up on other owners posts

https://www.broncosportforum.com/forum/threads/rear-differential-unit-rdu-replacement.10712/post-262979

Thanks you, definitely gonna be digging into this and arming myself well before taking it back in. I really appreciate it!

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