Why changing trans fluid is so critical

[Silverado12]

IMO I change mine as cheap insurance. The GMs are just dump and fill (FWD transverse tranny) and the truck gets the fluid and filter every 30K miles because it's used for towing. Yes, it's probably overkill but rather be safe than sorry as trannys aren't cheap.

 

[DoubleWasp]

It's not so much the sandblasting of the interior, viscosity changes, or the oxidation; although these are issues. It's the gumming and plugging.

Any transmission guy can tell you how many times he has seen solenoid packs or valve bodies malfunctioning due to contamination of the fluid.

 

[69GTX]

Originally Posted By: Leo99
My main beef is with the title of this thread. "... so critical" I contend it's not critical at all for lifetime fluids. I'm open minded. Show me the data that changing out a lifetime fluid provides a benefit.


Show us the "data" that lifetime fluid is equivalent or more beneficial than more frequent fluid changes. Let's assume a lifetime is 150K miles as mentioned earlier.

I've had a couple of early trans failures over the years....around the 75K-125K mark. I can only assume those occurred due to poor fluid maintenance. The one that went at 75K started having problems as soon as I bought it with 55K miles. Any trans over the past 20 years hasn't failed me before 200K miles (ie 25K-35K fluid changes).

 

[Rhymingmechanic]

My first thought after watching the video was that filters like the Magnefine might be beneficial if metal debris is as detrimental to the electronics as he says. The in-pan magnet catches what settles near it in the pan, but all of the fluid is pumped past the magnet in an inline filter.

"Lifetime" must be an effective marketing term for customers who don't think much about it. My guess is that it plays on the idea of a lifetime warranty, without ever defining what "lifetime" really means. The powertrain warranty, for example, is X months or XX,000 miles. A lifetime warranty usually states that the product is somehow guaranteed for the original purchaser as long as they own the product. "Lifetime" as it applies to ATF is no different than labeling it "improved" or "performance," but probably makes most new-car buyers feel more confident.

I'm probably guilty of over-maintaining my vehicles because I keep them a lot longer than the manufacturer would like. On the only vehicle I ever bought new, a 2001 Silverado, I did two pan drains and then a filter change around 37,000 miles. On the next pan drain, at 48,000, I noted that the fluid still had a little sparkle to it. Not long after, I pumped a few quarts out through the cooler line and installed a Magnefine filter. I haven't noticed any sparkles in the fluid since. The magnets are always coated in metal paste when I open the filters, but nothing beyond an occasional metal flake has been visible in the paper element. (The maintenance schedule for this truck called for a fluid/filter change at 100,000 miles, or 50,000 with towing.)

 

[KrisZ]

I know that if I buy a brand new vehicle with an auto tranny, I always dump the ATF at around 10k miles. Clutch packs shed the most material during break in, that will not be caught by magnets nor most AT screens.

 

[wtd]

My 2014 Mustang GT has the 6R80 that he mentions in the video. The problem with most of these new transmissions are that they either have no dipstick which makes changing fluid very difficult, or one like what's on my Mustang that is very short and mounted near the hot exhaust. The car also has to be level so that pretty much makes you have to have a lift. I plan on either changing it myself somehow or getting it changed at 30,000 miles. I'm at 24,000 now.

 

[WhizkidTN]

Originally Posted By: KrisZ
I know that if I buy a brand new vehicle with an auto tranny, I always dump the ATF at around 10k miles. Clutch packs shed the most material during break in, that will not be caught by magnets nor most AT screens.


I would agree with that. I was hoping that by installing the Magnefine at ~8K on my '12 Kia Optima that the internal cartridge filter would catch the non-metallic material.

 

[Artem]

I'll throw in my personal experience with MANY cars.

I flip used cars as a hobby / extra income. I come across A TON of cars that very obviously still have the original Lube in the tranny. The car shifts poorly and rough.

After a fluid change, the transmission INSTANTLY starts shifting better. Within 100 miles of use, it gets even better as the fluid cleans dirty parts and provides better Lubrication for better operation / performance. I then usually do another mini flush to insure extra clean and fresh Lube in the transmission for the new owner.

I personally feel the whole lifetime Lube movement is probably an effort to save oil and or lower the cost of maintenance for the ORIGINAL BUYER of the car while still under warranty.

Like someone else said earlier, most 10-15 year old cars with 150-200k miles are completely destroyed inside and out and need to be crushed / recycled because they are nasty, dirty and worn out rust buckets. I can see the original transmission Lube providing just enough protection to keep the transmission going in one piece just long enough to survive the use before it heads to the junk yard.

If 90% of the Millions of average daily beaters have lifetime Lube that nobody touches and then the cars go to the junk yard, technically... no harm no foul, right? The car is toast, interior is worn out, engine is leaking and burning oil and the original transmission fluid is also done and burnt to a crisp and will cause the transmission to fail soon.

Now, if you're trying to keep the car in 100% OEM spec ( LIKE NEW ) then no way can the word "Lifetime" be associated with your maintenance schedule. That fluid needs to go after 60-100k in order to keep the vehicle realiable, and that's not even considering the smoothness of the transmission operation. I personally prefer my cars to shift smoothly. Jerking and rough shifting is a NO GO to me.

I have 50k miles on my 2014 Mazda 3 and I've changed the transmission oil in the 6 speed manual twice already leading up to this point. I flushed the original fill after a few thousand miles of use and did another easy drain and fill at 30k miles. Both times the gears shifted MUCH smoother with fresh, new oil providing PERFECT operation of the gear synchronizers. Recently wifey said she noticed the gears getting crunchy again, so that's my que that another flush is needed to remove the metal shavings out of the system to allow for smooth operation again.

Our Mazda 3 is modified and dyno tuned. The transmission also has a shift shifter and stiffer bushings / engine mounts so I can FEEL the gears sliding into place. Once you get used to how it's suppose to feel when NEW, I swear I can feel the SLIGHTEST difference and degradation in shift quality, so to me personally, it's a no brainer that if you want 100% OEM spec, new fluids are needed throughout the drivetrain.

Those are my thoughts and personal experience with HUNDREDS of cars that I service regularly. Feedback from owners who leave my shop after a transmission flush and report saying "wow, it shifts so much smoother now" is all I need to know in regards to this subject.

Just my thoughts.

 

[demarpaint]

Originally Posted By: KrisZ
I know that if I buy a brand new vehicle with an auto tranny, I always dump the ATF at around 10k miles. Clutch packs shed the most material during break in, that will not be caught by magnets nor most AT screens.


I did it with my 08 Liberty and will be doing it with my 16 Rubicon when it reaches 10K miles. I keep my vehicles for a very long time. Most of them a lot longer than the national average, or the mfg. expects the vehicle to last. Servicing the transmission extends the life of the unit and can improve the shift quality as well.

 

[Artem]

Originally Posted By: wtd
My 2014 Mustang GT has the 6R80 that he mentions in the video. The problem with most of these new transmissions are that they either have no dipstick which makes changing fluid very difficult, or one like what's on my Mustang that is very short and mounted near the hot exhaust. The car also has to be level so that pretty much makes you have to have a lift. I plan on either changing it myself somehow or getting it changed at 30,000 miles. I'm at 24,000 now.


Even with no dipstick, if there's a drain bolt, measure what came out and pour the same amount in. Most transmissions have some type of way to pour fluid back in, even if you have to use a vent / breather tube to slowly pour it in.

 

[bbhero]

I believe what you have witnessed first hand. I also believe that one member on here has almost 300k miles on his vehicle's original transmission fluid. Plus this member has two other vehicles over 200k miles with the original transmission fluid. My lady's Sunfire had 214k miles with the original transmission fluid in it and it ran just fine. My Sentra ran great until 242k miles until the motors timing chain gave up. I don't know what first 118k miles of maintenance was like. I'd be willing to bet that the transmission fluid was never changed in it. And I don't know if the motor was changed in a reasonable matter in the first 118k miles. But from 118k to 242k miles I changed the oil out in that car every 4-5k miles. The motor had terminal trouble and not the transmission.

I do not in any way shape from or fashion would suggest that changing out transmission fluid regularly is a bad idea. In fact, I believe that is a exceptionally well rationaled maintenance program to endeavor in. Replacing the fluid can only be a positive action to be taken. Given.... It is the correct fluid that meets the OEM specifications. And not some fluid that "claims" to meet a whole bunch of different OEMs transmission specs who all somehow are "magically" using a remarkably similar formulation. Which I find to be quite spurious at best. This is especially the case with aftermarket CVT fluids that are being pushed as good for multiple OEM platforms. People striving to save 4-6 dollars per quart with these supposed multiple meets specs CVT fluids are gambling far more so than if they just left the original fluid in there. When it comes to CVT transmission fluid I strongly believe that using the OEM fluid is the best practice for now.

When it comes to the Ford or GM transmission fluids I would suggest that the aftermarket offerings are fine for older specifications. If it is the latest version of Dexron or Mercon than I would go with the OEM fluids. I wouldn't want to be a guinea pig for the aftermarket fluids on the newest generation of either of those two fluids.

The Nissan CVTs have shall we say a "oil life monitor" on them. They have a degradation number of 210,000 in which at that time the original fluid needs to be changed. I have done a whole lot of research and reading about this and have found that if extrapolated out from the numbers I have found that it would not need to be changed in many of the vehicles that had their CVT fluid tested. Now, having stated this I believe that it would be just fine for someone to change it out prophylactically if so desired. I would suggest that if one lives in the southwest US it would likely be of more benefit than other areas. Due to higher ambient temps and much more dust in the air makes this a very understandable and well rationaled approach. Again, instead of cheaping out and getting another supposed fluid that meets NS-2 and a number of other specs I would suppose that it would be best to just pony up for the OEM CVT fluid.

Changing fluid does not overcome mechanical or computer problems with transmissions. The latest generation of CVTs in Nissan are an example of this. The latest JATCO CVTs have been rather problematic. These CVTs are having far more problems than they should be. I have driven a 2015 Nissan Altima 2.5. It would be my hypothesis that the problem is with the fact that these CVTs never quite trying to find a higher gear ratio. Thus, these CVTs never get a break from this type of operation. I believe this is a major part of the problem with the latest generation of CVTs from Nissan. You could change the fluid all you want and it will still not fix the real causative problem.

Again, I fully support prophylactically changing one's transmission fluids. It can only be a positive step to be taken given it is a legitimate OEM fluid or a truly equivalent aftermarket fluid. I have 170k miles on my Nissan Altima 3.5 with the original CVT fluid in it. It has been absolutely fine. I do have a fluid evacuator to change out the fluid. I will be doing this slowly over the next year at 3 quarts at a time.

 

[WhizkidTN]

Back in the summer, I had my wife's '14 Nissan Rogue's CVT (AWD) serviced at the dealer for the ATF change. This was about at 30K miles. While the manual says I could go 60K before changing it the first time, the service manager stated that they have seen many issues with these new generation CVTs ('14 was first model year for this Nissan internally developed CVT) when going that long and recommended the simple fluid drain/fill (OEM factory method and fluids) every 30K miles or so (cost is $130). I did that along with doing a drain/fill of the rear diff and the center transfer case (w/M1 75W-90 gear oil) just to have fresh fluids throughout (cost me $50 in fluid/labor). Well worth my peace of mind on the subject.

 

[Alfred_B]

Originally Posted By: andyd
I think the bean counters breathe a sigh of relief every time a car's warranty expires

Warranty is a liability that's estimated and booked based on historical averages. In the big picture it doesn't matter on its own. Every car buyer pays a fraction of that liability.

It matters for customer perceptions and marketing.

 

[grampi]

Our 2015 Sienna has lifetime fluid and I plan on changing it out at 100K...certainly couldn't hurt...