Rear End Failure

[BeyondEOD]

S606D - 3.58, 8.8. 3.0L ST
Replaces: S-606-B, L1MZ-4000-D

 

[BeyondEOD]

https://www.fordpartsgiant.com/part...differential-drive-axles-propeller-shaft.html

 

[musclecarman39]

I thought the diffs in the 2.3 vs the 3.0 models were different ratios, but according to this they're the same. The difference is between the diff in the King Ranch/Platinum (3.31) vs the ST (3.58).

https://www.vdm.ford.com/content/da...owing/pdf/2024-Ford-Explorer-Towing-Guide.pdf

It's a small difference but enough to cause the vibrations/bucking. It looks like every Ford parts site uses the same specs no matter where you look, and they all say both part numbers are compatible with all models, so it's really confusing. But that's my guess, the S602D is for the King Ranch/Platinum.

That's what i finding out, the S602D is for the Platinum and 3.31 gear ratio.

 

[musclecarman39]

S606D - 3.58, 8.8. 3.0L ST
Replaces: S-606-B, L1MZ-4000-D

That is actually the first rdu they put in my ST after the original went out. Then after about 700 miles i started getting a vibration when accelerating and a loud howling noise so they replaced it again with the S602D and that's when the bucking started. Then they said my transfer case was bad and causing that issue and guess what, I still have the bucking issue and they put the wrong transfer case in! The transfer case they put in is L1MZ-7A195-C which is for the 2025 explorer, the B is for the 2020-2024. So the 2nd dealership I've taken to found that both the rdu and tc are wrong but are telling me that the rdu is supposed to be the S604B which went to the S604D but everything i see says it's for the hybrid rwd. The second dealership can't replace them with the correct ones under warranty because they aren't bad, they are wrong and i have to go back to the original dealership and get them to install the correct ones. I'm getting really mad because this has been going on since the middle of October and I haven been able to drive my car.

 

[BeyondEOD]

S604D is for a RWD model. There are 3.0 RWD cars out there.

 

[BBGun242]

Anyone that got their diff replaced what was the labor quote for that? I have 89,000 miles and pretty sure my front pinon bearing is on it's way out.

 

[musclecarman39]

To the guys that have had the wrong rear diff installed, what was the part number of the correct one that was installed? I'm getting conflicting part numbers from different dealerships? I'm being told S604D by 2 dealerships and S602D by 2 others. The S602D is currently in my ST and that's when the vibrations and bucking started.

Ok so my ST is FINALLY fixed after 2 months and 2 dealerships. I had to take it back to the original dealership to get it fixed. I gave them the info from the second dealership about the rdu being the wrong one. Neither dealership could find the part with my vin# as the search would say there wasn't one available. I called several dealerships and same issue. So the original one opened a case with Ford engineering and they confirmed the correct rdu part# for the ST is S604D. They also said there is an issue with their catalog causing the vin# search turning up nothing that they are trying to fix and there have been a lot of incidences like mine happen. This is now the 4th rdu put in my car, including the original. The first replacement they installed was the S606D which lasted about 600 miles and started howling, then they installed the S602D and that's when the bucking and vibrations started. So now it's back to normal with the S604D. I love my ST but the last 2 months have been hell!

 

[enphor]

Ok so my ST is FINALLY fixed after 2 months and 2 dealerships. I had to take it back to the original dealership to get it fixed. I gave them the info from the second dealership about the rdu being the wrong one. Neither dealership could find the part with my vin# as the search would say there wasn't one available. I called several dealerships and same issue. So the original one opened a case with Ford engineering and they confirmed the correct rdu part# for the ST is S604D. They also said there is an issue with their catalog causing the vin# search turning up nothing that they are trying to fix and there have been a lot of incidences like mine happen. This is now the 4th rdu put in my car, including the original. The first replacement they installed was the S606D which lasted about 600 miles and started howling, then they installed the S602D and that's when the bucking and vibrations started. So now it's back to normal with the S604D. I love my ST but the last 2 months have been hell!

Thank you for sharing your experience with us. I'm sure your update will help many out there until Ford can get it's head out of its ass.

 

[hbalek]

Ok so my ST is FINALLY fixed after 2 months and 2 dealerships. I had to take it back to the original dealership to get it fixed. I gave them the info from the second dealership about the rdu being the wrong one. Neither dealership could find the part with my vin# as the search would say there wasn't one available. I called several dealerships and same issue. So the original one opened a case with Ford engineering and they confirmed the correct rdu part# for the ST is S604D. They also said there is an issue with their catalog causing the vin# search turning up nothing that they are trying to fix and there have been a lot of incidences like mine happen. This is now the 4th rdu put in my car, including the original. The first replacement they installed was the S606D which lasted about 600 miles and started howling, then they installed the S602D and that's when the bucking and vibrations started. So now it's back to normal with the S604D. I love my ST but the last 2 months have been hell!

Mine is doing fine with 606D installed over 2 months and 2000 miles ago. They said it was mislabeled last summer the first time they replaced the RDU.

 

[musclecarman39]

Thank you for sharing your experience with us. I'm sure your update will help many out there until Ford can get it's head out of its ass.

You're welcome and I hope no one else had to go through this. Hopefully Ford gets its shit together soon.

 

[musclecarman39]

Mine is doing fine with 606D installed over 2 months and 2000 miles ago. They said it was mislabeled last summer the first time they replaced the RDU.

Mine did ok with the S606D, the first replacement, it just didn't last very long. Hopefully this S604D does.

 

[enphor]

I'd still like to understand the reason for so many RDU failures in the first place. Is it poorly designed, poor QA, shitty materials, installed improperly, undersized mounting system causing excessive movement, undersized in general for the power it is handling? All of the above?

 

[musclecarman39]

I'd still like to understand the reason for so many RDU failures in the first place. Is it poorly designed, poor QA, shitty materials, installed improperly, undersized mounting system causing excessive movement, undersized in general for the power it is handling? All of the above?

Those are all good questions. I always considered 8.8" rdu's to be good units. The one in my 95 tbird is still going strong

 

[hbalek]

Ever since they replaced the FADA up front I started having PTU and RDU problems. Coincidence?

 

[musclecarman39]

Ever since they replaced the FADA up front I started having PTU and RDU problems. Coincidence?

I'd wonder the and thing. Isn't that what gets replaced with a solid shaft