More RDU issues

[BS FE 21]

I finally got around to changing the RDU oil today. I have a 2021 First Edition with 39k miles and I am the second owner. When I got under the rear end for a good look things were way cleaner than I expected. I am quite sure there has been no rough treatment on this vehicle. I drained the oil which looked pretty much brand new. Clear and clean oil. Pumped in new fluid. I'm going to leave the original vent hose on for now. Maybe sometime down the road if I'm feeling frisky (doubtful) I will upgrade the vent hose. I'm in my 70's and never been too crazy about crawling under vehicles.

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[toddedmond]

I changed both the RDU and PTU fluids this weekend. My 21 OBX has 65000 miles now. I had the RDU unit replaced under warranty at around 46000. My RDU fluid after 18000 miles was very black, so I would recommend 30000 miles max. The PTU fluid, which is original was still brown, but was pretty cloudy looking. I would say 60000 would be wise.

 

[DSB Snag]

Had a similar experience with my dealer, who’s always done well for me. Service writer said Ford won’t authorize TSB unless there’s a documented problem w/RDU. Solution would be, “complain of noise/shudder from RDU when you bring it in for service”. Since there seems to be trouble getting vent replacement I, too, will probably just make my own extension and get a fluid change.

Talked to the local Ford service department. They knew nothing about the TSB so I showed it to them on my phone. They told me they could do nothing unless the RDU was causing problems. TSB are only information for the techs. I pointed out that it might be a good idea to be proactive to prevent a major failure. I also said that it should be covered under the drive train warranty. My BS only has 38k miles. "Too bad. Take your chances. Get in touch with Ford. Nothing we can do". By the time it was done I had a half dozen guys from the service department standing around listening. The guys weren't disrespectful or nasty, just pretty much disinterested. I'll pursue with Ford but don't expect any results. I got the service guy's card but his supervisor didn't have one. I've found that when people know their names are going to be out there they become more interested.

Same problem here. Our badlands had 38K. We have a platinum extended warranty up to 90K miles. they declined coverage as it was a hose. the power train warranty also declined coverage as it was a hose.

Dealership quoted $367 (plus a $200 diagnostic fee). I got them to take $100 for the diagnostic fee as I told them that would have been my deductible with the extended warranty.

I bought the part ($23) and took it to my local trusted mechanic. unfortunately the TSB shows it requires drilling into the frame and putting in a rivet and solder. This caused my local mechanic to decline to do it so now I have to go back to the dealership.

Since I own the part I'm unsure if they are going to still charge me $367; but, the TSB says its .9 hour of labor and I should only be paying the labor (at $200 an hour).

 

[DSB Snag]

So the TSB addresses a manufacturer's defect that can cause a catastrophic RDU failure possibly putting you on the side of the road. The TSB will not be enacted unless the RDU at least shows signs of failure (the shudder). The TSB vent replacement will not be considered part of the drive train so the customer is on the hook for parts and labor. Way to stand behind your product Ford.

exactly what we were told. it's a hose and not part of the drive train

 

[Dude]

"aka drain tube"
aka sippy straw

Similar for the 2025 model … note that the RDU Vent Hose is clearly shown on Ford’s 2025 build to order Powertrain page:

 

[Major Kong]

more favorable weather is finally here
shade tree mechanic skills initiated
prepping to make the RDU vent modification
but before committing
quick question addressed to the group
can anyone confirm if the PTU has a vent
it would seem a gearbox would have a need for one
if so my point
two birds one stone
preliminary concept
run RDU vent hose to firewall
run PTU vent hose to firewall
common manifold to vent device

 

[Dude]

more favorable weather is finally here
shade tree mechanic skills initiated
prepping to make the RDU vent modification
but before committing
quick question addressed to the group
can anyone confirm if the PTU has a vent
it would seem a gearbox would have a need for one
if so my point
two birds one stone
preliminary concept
run RDU vent hose to firewall
run PTU vent hose to firewall
common manifold to vent device

I need to look up the math and physics
Wouldn’t you need a larger diameter vent hose to vent the RDU across to the vehicles firewall
Maybe even an air pump ?

 

[Major Kong]

I need to look up the math and physics
Wouldn’t you need a larger diameter vent hose to vent the RDU across to the vehicles firewall
Maybe even an air pump ?

thinking cap material
my guess is we're not dealing with CFM
at best a couple cubic inches in volume bled off as temps slowly rise
reverse flow same unless there's a rapid cool down
aka stream fording
in which case negative pressure may occur in the rear unit
so
your advice will be noted in the concept drawings under review
thanks dude

 

[Dude]

thinking cap material
my guess is we're not dealing with CFM
at best a couple cubic inches in volume bled off as temps slowly rise
reverse flow same unless there's a rapid cool down
aka stream fording
in which case negative pressure may occur in the rear unit
so
your advice will be noted in the concept drawings under review
thanks dude

Good points… and I didn’t mean an air pump to move large volumes .. just that air trapped in long horizontal sections of tubing might resist movement to vent

 

[Major Kong]

Good points… and I didn’t mean an air pump to move large volumes .. just that air trapped in long horizontal sections of tubing might resist movement to vent

kong jr ran the numbers
all indications satisfy original concept
however
as a precaution the comfort factor will be introduced
will bump up the hose diameter
still curious if the PTU is vented
exploratory makes the to-do list

 

[Major Kong]

no clue pertaining to venting
but did find some relevant info of interest
https://www.aam.com/media/story/aam-s-ecotrac-ptu-featured-on-ford-bronco-sport

 

[Major Kong]

may have found answer to vent question
surprised to see vent only slightly higher than propeller shaft
which raises a question
if water levels exceed propeller shaft could this compromise the gear oil/PTU unit

 

[Mark S.]

may have found answer to vent question
surprised to see vent only slightly higher than propeller shaft
which raises a question
if water levels exceed propeller shaft could this compromise the gear oil/PTU unit

This is a different PTU than that used for the Bronco Sport. Refer to the first video you posted. The PTU only turns when power goes to the rear wheels.

 

[Major Kong]

This is a different PTU than that used for the Bronco Sport. Refer to the first video you posted. The PTU only turns when power goes to the rear wheels.

video intention to display possible location of the PTU atmospheric vent
sorry for the confusion
the video start time was forwarded to the segment pertaining to the vent
but yes it is a different PTU than the bronco sport
still curious though
why a vent might be positioned anywhere near a potential water submersion

 

[Mark S.]

still curious though
why a vent might be positioned anywhere near a potential water submersion

I don't believe the 2011 Edge was ever intended to be driven off-road like the Bronco Sport.

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