Transmission Issues and Mini Chronicles

[Tinytruck1369]

Just putting this out into the ether as a PSA. I figured I would document this journey for anyone interested...I'm a heavy believer in internet bias and that people only mention the bad things and not the 99% of the "everything is good" times.

Background

I took my 23 XLT FX4 to the dealer for an oil change and PTU drain and fill @ 80k miles (yes I could have done it at home, but I didn't). I am fairly attentive to my truck, with all fluids and mechanicals taken care of. I am a car guy at heart, but I'm a busy guy.

I had the dealer ask if I wanted to do a transmission flush. I have been subscribed to the old addage of "I haven't changed it yet, and Ford says 150k" . Dealer pestered me into doing it, so reluctantly after an exhausting day of work, I said "fine".

Boy was that a mistake....my transmission issue free Mav now slips, blips, over revs, misses shifts, and bangs into gears on hard acceleration. It's all over the place between 1st and 3rd and up to 4th

My day job I am a researcher...I document everything down the minute.

Trip 1 to the dealer they told me "they could not replicate" take the Mav home

Trip 2 to the dealer (the following day) the dealer says "oh we noticed it this time". We will wipe you transmission tables, give it 200 miles and it will fix itself

500 miles later, she is up to her old trucks of skipping and clunking her way through the gears.

Trip 3, as I currently sit here does not sound promising. I will update as I go along

Did I royally tempt fate with this transmission flush...were the horror stories I heard true. My solace is my 100k extended warranty, but man was I not expecting this.

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[CaReviews]

Following the 150k mileage interval on these will absolutely result in premature transmission failure in most cases. Servicing these every 30k seems to be the best advice, and was Fords recommended interval prior to the 8F35 being introduced. And anyone that thinks the ULV Fluid is good for the 150k well, your results may vary!

 

[scott1070]

Drain and refill the transmission. Never perform a flush

 

[RFEJR]

Drain and refill the transmission. Never perform a flush

My understanding is a flush is one of the worst thing you can do to this transmission.

 

[Tbone289]

The lesson here is that you don't want to wait until 80K to maintain the fluid in an 8F35. The 8F35 is hard on the ULV transmission fluid, and the internal filter is non-replaceable without cracking the case open. Many times failures in these are due to the filter clogging and starving the pump. This can be exacerbated by "flushing".

Drain & fill on a regular basis, no more than 30K between services. Note that a drain and fill only replaces less than 1/2 of the fluid, so a single drain & fill only "dilutes" the old fluid with new. For a more complete fluid replacement, some transmission techs recommend you do 3 drain and fills in short succession.

 

[scott1070]

My understanding is a flush is one of the worst thing you can do to this transmission.

Yup. In over 49 years of driving, the only time an automatic transmission has given me problems was shortly after someone performed a flush on it.

 

[Tinytruck1369]

Yup. In over 49 years of driving, the only time an automatic transmission has given me problems was shortly after someone performed a flush on it.

I had originally asked for a drain and fill when it was suggested . The service advisor told me that they only do flushes there, which I am sure is a lip service mark up line.

 

[Tinytruck1369]

4/23 ***Update*** in the words of Bender...welp she's boned.

Dealer is currently processing a complete transmission replacement under the warranty. To be honest I'm not sure they did any additional diagnostics or if the labor rate at this point isn't worth the time. Was assured this is a new unit from Ford and it would take 2 weeks to get shipped to NY

Warranty coming in clutch here....but still wish I had found the 30k swap interval advice a few years ago.

 

[Tinytruck1369]

The lesson here is that you don't want to wait until 80K to maintain the fluid in an 8F35. The 8F35 is hard on the ULV transmission fluid, and the internal filter is non-replaceable without cracking the case open. Many times failures in these are due to the filter clogging and starving the pump. This can be exacerbated by "flushing".

Drain & fill on a regular basis, no more than 30K between services. Note that a drain and fill only replaces less than 1/2 of the fluid, so a single drain & fill only "dilutes" the old fluid with new. For a more complete fluid replacement, some transmission techs recommend you do 3 drain and fills in short succession.

My issue is that aside from online advice from good folks such as yourself, Ford is pretty adamant about the 150k when I have asked in the past. Lesson learned

 

[Tinytruck1369]

Following the 150k mileage interval on these will absolutely result in premature transmission failure in most cases. Servicing these every 30k seems to be the best advice, and was Fords recommended interval prior to the 8F35 being introduced. And anyone that thinks the ULV Fluid is good for the 150k well, your results may vary!

Agreed and thanks for the suggestion!
It's seems to be fairly bad practice for most car owners to not get reliable service intervals spelled out in maintenance guides. The whole meme of "did you read the manual" really goes out the window here. The answer was yes, and I was wrong to do so. As I am sure many less mechanically inclined owners will be. Seems to be a sure fire way to piss off your customer base!

 

[Tbone289]

My issue is that aside from online advice from good folks such as yourself, Ford is pretty adamant about the 150k when I have asked in the past. Lesson learned

Yeah, I wasn't trying to pour salt in your wounds, I was just trying to impress on everyone else that might read this how important this is with these transmissions. I'm sorry you're having to go through this...

 

[Tinytruck1369]

Yeah, I wasn't trying to pour salt in your wounds, I was just trying to impose on everyone else that might read this how important this is with these transmissions. I'm sorry you're having to go through this...

No worries! I agree with you. I hope this whole thread helps someone out there! Toss the service manuals at your nearest service advisor (please don't)

 

[SafetyGuy]

No worries! I agree with you. I hope this whole thread helps someone out there! Toss the service manuals at your nearest service advisor (please don't)

I am so sorry to hear this happened to your truck, but I am also very thankful you have warranty to take care of this problem...and I am also hoping many others hear about how bad of an idea it is getting transmission flushes...and to not wait too long between changes!

I used to think it was a good idea (getting flushes) till something like this happens and we learn.

I hope all goes smoothly on the transmission change, so you can put this all behind you.

Andy

 

[Chops]

I’d say drain/refill (not flush) every few years or so - or just leave it in “forever”.

I’ll let AI explain what I already know:
“Automatic transmissions use clutch packs and bands that engage for shifting. Over 100k–200k+ miles (or 50,000 on a EB?) these wear down and shed friction material (metal particles, clutch lining bits) into the fluid. This suspended grit and thickened, contaminated fluid increases “grip” or friction on the now-smooth/worn clutch surfaces. It can prevent or reduce slipping in a transmission that’s already marginal”.

I added the “50,000 on an EB?” part…
I let “Jiffy Lube” do the first drain/refill on a 200,000 mile Vibe (Corolla). Shifted jerky a bit at first - but got back to normal after a few more thousand miles. Luckily there was still enough “dirty” fluid remaining in the trans. I think a drain / refill only adds about half the capacity?

 

[Timothyd]

The lesson here is that you don't want to wait until 80K to maintain the fluid in an 8F35. The 8F35 is hard on the ULV transmission fluid, and the internal filter is non-replaceable without cracking the case open. Many times failures in these are due to the filter clogging and starving the pump. This can be exacerbated by "flushing".

Drain & fill on a regular basis, no more than 30K between services. Note that a drain and fill only replaces less than 1/2 of the fluid, so a single drain & fill only "dilutes" the old fluid with new. For a more complete fluid replacement, some transmission techs recommend you do 3 drain and fills in short succession.

I used to like that my old Saturn had, for the transmission, a spin-on filter that was easy to get to. Wish they all had that.

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