How often should transmission oil be changed for the newer super duty 6.7 diesels when used to pull a heavy fiver 75% of the time. The manual says to change it at 150,000 miles. I can find nothing that says to change sooner when towing. What do others do?

 

What you have read is all there is.


I will be changing (flushing actually) at 60K.


The newer fluids are suppose to allow a longer interval but I will opt to be on the side of caution.

 

I agree with Senix except that I will probably do mine at 50,000 just because it's easier to remember.

 

The irony is that if you pull into some places asking for a tranny flush with let's say a 10 year old vehicle and 150,000 miles they won't want to touch it if it's never been flushed. Fresh oil will knock loose 10 years of dirt/varnish etc and your tranny will quit working. Some shops don't want blamed for that.

 

My plans are to start changing the fluid in the pan only at 30K then the pan and filter at 60K and keep that schedule until I'm done with the truck.

Denny

 

That's an old myth that is NOT true.

What DOES happen is that many people ignore the trans and never service it. Then trouble starts and they hope that changing the fluid will fix it. It doesn't fix it, it's already failed. Now when it dies they blame the fluid change, not the years of abuse and neglect.

 

Bingo, just a myth that won't die!

Also with the robustness on the fluid used in the newer SD trucks plus the cooling capabilities, there is absolutely no reason to change it any sooner than 100 k miles.

If you really think you need to, at least consider sending out a $20 oil sample out for testing before wasting dollars and resources!

 

If 150,000 miles with 75 % of that towing is the recommended service interval...what does Ford consider abuse and neglect? At 35,000 miles and 3 years mostly highway and no towing the fluid in my Taurus X came out pretty darn black and it's a long way to 150,000 miles.

 

So do you think I have the right maintenance schedule with my 30, 30 pan changes?

Denny

 

Comparing the 6R140 with a Taurus is apples to democrats.
Ford says nothing about any % towing, which is the dilemma. At the very least Ford should have addressed the issue, especially considering that most trucks sold are used for some towing, and it's just a guess, but I suspect 90+% of super duties will tow something on occasion.. I get that there are an infinite number of variables, but some guidance would have been the right thing for the customer...but, I also get that "right thing for customer" is not #1 now its it?
All that said, we are all left to solve a question for which we have very little data. And to further complicate things, it's being stated in some venues that by changing the oil, somehow things can get screwed up....never to be the same. That's hard to believe if a proper hot flush is performed, but this rubbish still gets our attention. I say all that to explain why this exact same question keeps popping up on Superduty forums all over with only a bunch of educated guesses and personal opinions. Except for me where my educated guess is indeed my opinion.

 

I'll connect the dots for you, dg53. Claims were made that in essence said exceeding Ford service intervals was a waste of money. I used the Taurus example to accentuate what customers see. If fluid turns black quickly in a mild use vehicle, what might it do in a heavy use vehicle...especially at much higher mileage?

As for flushing a long over due tranny causing problems, I never said it was true, but every mechanic I have ever asked has stated this exact concern and will not flush a high mileage vehicle that hasn't been flushed previously. They don't want to risk a complaint.

For my auto trannies, I flush at half the mileage that Ford recommends because I want to keep my cars/trucks for 15-20 years. Ford has already given you their best answer. It's up to you to determine where your comfort level is. I spend a little extra on fluid and then sleep like a baby.

 

Ford builds these trucks with the expectation that they will be used for things like towing 75% of the time or above and I would expect their service intervals to reflect this. The torqueshift is a huge transmission with lots of fluid, a filter and lots of cooling. The newer synthetic fluids protect for much longer. I would not change it any earlier than 100,000.

 

When it comes to auto lube, color is not an indicator of performance....another old wive's tale that won't die.

Oil sampling is the only way to know exactly. Otherwise follow the mfgers reccomendations as they have put the engineering and testing time into those values.

 

100% agreed...you have to test it to know for sure. However, for the average consumer it's hard to feel comfortable following mfgers recommendations when the oil is black way, way before the service interval is reached.


I actually worked as an R&D chemist for a company that makes/tests these fluids. Now I'm in a different industry but the principles are the same. Marketing asks the chemists and engineers to develop a product and puts on time restraints as well as cost constraints on the product. We (chemist/engineers) come back with the best we can do in the time/cost allowed and present our testing. The testing is a blend of simulated and "real world" testing. The testing is never 100% indicative of every customers' situation and simply cannot predict all modes of failure. In the end, the product is marketed with a margin of safety. Sometimes the safety margin is built into the product. Sometimes the safety margin is in how much risk the seller is willing to deal with if/when the customer has issues. Given all the variables, it's hard for guys like dg53 and me to have 100% confidence in following mfger guidelines to the letter. For guys like us, we try to balance how much extra money we spend on maintenance against our comfort levels while trying to make our vehicles last.

 

OLD wise tails... Man...


someone need to find a way to "KILL" old wise tails.. in todays Electronic Communication World.


The older I get the more I hate them...
and can you believe the "Chrome Muffler Bearing" is still floating around.
along with Red Blinker Fluid.
Winter AIR, Summer Air for tires.


going on 4 generations Now.


for oil/fluid.. Normal use, Heavy Duty use, extreme use.


oil/fluid is the LIFE of your machinery .. treat it accordingly . my opinion.