Samurai Edge

Just an update on the Disconnect RDU gear oil: Ford Recommended Gear Oil = Motorcraft Rear Axle Oil - XY75WQL at a mere $32.99 on Amazon. I just got off the phone with Redline Technical Service. According to Redline, their corresponding oil will be Red Line 50604 MT-LV 70W/75W GL-4 High-Performance Full Synthetic Gear Oil Lubricant for Manual Transmissions & Transaxles - 1 Quart. for $22 on Amazon Nothing apparently available from Motul. Just an FYI for those interested. Also Note: While it's true as stated by someone earlier, Ford can't deny you ( allegedly ) any claim if you use Ford Recommended products. However, in reality, the manufacturer can't deny a claim as long as you use the appropriate grade product, IE; if you use a comparable 5W-30 motor oil other than Ford product, all else being equal, they can't deny you. Just remember to use quality products, not some cheap version from Walmart, etc.

Overall, I don't disagree with what you are saying, hence my belief to change fluids at a faster rate than OEM usually recommends. Could all be due to meeting certain EPA mileage requirements ( thinner oil = less resistance = easier turning = less fuel used ) but I don't have access to the knowledge base that designed the Disconnect RDU and why Ford states only 75W for this RDU. That's why I'll stick to the recommended 75W for the RDU until I see more, certified information on switching to a thicker gear oil. Same goes for the PDU. However I would not use straight Redline Heavyweight Shockproof ( Film thickness greater than an SAE 75W250, yet low fluid friction like 75W90 ) in the PDU as some have suggested. That stuff is designed to cling to metal and use only in splash boxes. Read multiple reports in the past of people who have used Redline Heavyweight Shockproof in their gearbox and when they took it apart, they found a thick sludge of " Smurf Blood " packed in around the gear case that had to be removed. Redline Lightweight Shockproof is a 75W80 so I would definitely consider using that in the PTU. Always worked great in my 5spd and 6spd with zero issues and smoothed out the shifting

Well, the Japanese do things differently than we do in the US. 🫠

Just a comment for clarity Enigma-2 said " Second that. Drilled slotted rotors have more heat resistance after hard braking, but actually degrades stopping on a street car (holes and slots in the disks have less braking surface area to press against.) To increase hard braking, wider tires work better. (Once any braking system locks up, the only factor left in stopping to car is the friction between the tires and the ground. The more tire surface in contact with the ground, the more friction exists.) " I agree wider, stickier tires give better braking performance than lesser tires. However, saying that drilled / slotted rotors degrades stopping due to less braking surface I believe is not correct. The amount of material removed is negligible to the overall disk material. Additionally, I have never used drilled rotors but I have used slotted rotors in the past. I don't believe they increase or decrease stopping distance in of themselves ( see tires and brake pads ) BUT the slotted rotors do help stopping distance in the rain as the slots allow the disks to shed water between the pads and the disk faster than solid disks.

The STs have electronic steering so there is no PS fluid. My Dealer recommends the RDU at 30K miles, the PTU they reluctantly say 30K miles and the transmission they say 5 years or 30K miles, which ever comes first. Per manuals, I find brake fluid at 3 years ( no mileage ). Coolant, depending on your source could be anywhere up to 100K miles. However, I typically use the Severe Duty schedule when looking at maintenance service schedules, so those values are typically much shorter than the standard maintenance schedules STBEAST - You don't want to use Redline Shockproof ( either variety ) in either your PTU or RDU. Way too heavy. The PTU calls for 75W85 and the RDU calls for 75W for disconnect RDUs. Apparently only Ford has the 75W fluid available, which can be pricey but it appears it is a special formula specifically for the Disconnect RDU. The Disconnect RDU engages or disengages depending on vehicle engine load. If it were me\, I would only use the 75W

At worst, the only warranty denial Ford can apply is if they can show if the tune was the result of the engine or engine-related part failure. All other warranty items will still be covered. Doesn't matter if you have the extended warranty or not. Now, if Ford says that's the issue / reason, you are really out of luck unless you want to fight Ford Corporate lawyers. Depends on your Dealer as they have discretion on informing Ford regarding issues and warranty work.

I had the same issue with my 2020 Edge ST with only 20K miles. There is a TSB that covers this. A PDM update resolves the issue. However, if the RDU fluid has never been changed, or if the wrong fluid was used, then the RDU fluid should be changed soonest.

Hi Davidoo I have a 21 ST and it does not have the PTU cooler either. As STBEAST said, how much is the cooler really worth if you are cycling 200* coolant through it? You also said, " As a side note, I changed the RDU myself and only got about 22 ounces out of it when the specs say it holds 28 plus/minus an ounce. I'm glad I did because it came out completely black, and a lot of sludge stuck to the magnet on the drain plug. I got 26 ounces back in it before it started pouring out the fill cap, so that's all I could get back in. " Per the Oner's manual, the RDU takes approximately 28 ounces. The only way to get just about all of that out is if you pull the RDU cover and let it all drain. You can only get so much out via vacuuming it out.