Trans Drain/Fill: How Many Times???

So if it’s to each their own, why are we discussing it?

 

I had an opinion and a tip to offer.

If you're comfortable changing half your fluid at a time it's my opinion that's better than doing nothing.

 

If the fluid is burnt your transmission is already fucked.

But someone brought this point uo a week or two ago so I’m just copy paste my response from that thread.

“Apples to oranges.

Look at how often you change the filter on those two fluids. Engine oil filter is every 5-10k miles depending on driving conditions, but the transmission fluid filter is just a metal screen that has no change interval. There’s a reason for that.

Engine oil brakes down and gets contaminated quickly. Cold starts are going wash fuel past the ring into the oil. The engine is always going have some amount of blow by where spent gases are pushed down into the the crankcase where it’s surface filtered by the oil while vented via the PCV system. Engine internals are an extremely dirty environment.

Non of that is the case with the transmission. There is no combustion happening, it’s just a sealed unit using a fluid for its hydraulic function. Replacing some of the fluid, which is very long life, from time to time will have no detrimental effect.

You’re comparing a transmission drain and fill to changing half your oil, but in reality it’s more along the lines of filling your fuel tank. Gasoline has a shelf life, it goes bad over time, but how many times have you drained your fuel tank and flushed the lines? I would guess zero. You gradually put in new gas that mixes with what’s left of the old stuff. The result is cycling through fluid before it’s actually old enough to go bad.”

 

Well said

 

Good point.

 

My guess is that a periodic drain and refill is fine, and maybe even doing nothing is fine, but spending $250-$300 every 60,000 miles to do a flush gives me a little bit more peace of mind. Given that I started doing it at a little over 60K there hopefully isn't a significant risk it could cause the clutches to slip like it might if I got a first transmission service at 150K. I went back and forth on all 3 options before deciding to go with the flush. I drove a 2001 Toyota Highlander from 47K to over 250K miles and am not sure I ever had the transmission serviced.

 

UPDATE: Well, I finished it in about an hour and a half. Pretty straightforward, drained about 2.9 quarts, color was really good for a first trans trans service at 83,313 mi. - dark, but still a little red. Refilled a little extra with ATF WS, used my OBDlink MX+ to read the temp (by the way, I found a spot on the drain pain that gives a ± .5 - 1 degree correct temp reading with a Harbor Freight laser temp gun). Drained about .5 quart from the stand pipe at 104 degrees.

Shifting and driving smooth - thanks for all the input.

 

Only issue is I always say I'll fill up gas in the morning while riding on E all day.

So not much old gas to mix LOL.

 

So you pay around 300 for the dealer to do the trans flush? how does it feel afterwards? I wouldn't mind paying 300 for that seems okay at this time as everything went up in price.

 

I did a dealer fluid exchange at 90k miles on my 2010 Corolla and haven't had any issue afterward.

 

What is the transmission Failure rate for 5th gen 4 runners using each method? Is the failure rate difference statistically meaningful? I prefer to make data driven choices, and it seems like with all of the 4Runners in service, discussions like this should not have to rely on anecdotal hearsay. I am starting to think my 4runner might fail from a rodent eating the wires long before a transmission failure because of drain & fill vs flush.

 

Not much data out there.

Even for those who don't change the trans oil at all, you still don't hear about failures.

 

My service advisor at the dealership told me that they only do the drain and fill to alleviate the possibility of waking up the transmission gremlins.

 

I did a pan drop/filter replacement at 102k it was over kill.

https://www.4runners.com/threads/transmission-pan-drop-filter-replacement.32643/

I'd recommend 30k drain and fills and a 200k pan drop.

 

I had the dealership flush my 2019's transmission at around 90k miles. The thing I noticed afterward is that it seemed like the truck was sort of back to the original shift pattern (like when it was new). It slowly re-learned my habits and is great now. You know, shifts are smooth and occur when I want them to occur. I don't know if there's a software reset/update when they do this, or if it's a result of the new fluid. But they said the fluid looked good when they flushed it. Yes, I have a good relationship with the service advisor, so I think I'm getting good info.

As a side note, I had this done to my son's 2016 Corolla's CVT, and it made a world of difference. In his case, there was a software update, too.

 

I see CVTs as a different animal altogether. I frankly am just not convinced on their longevity. Im probably wrong and that is just based on the reputation of older CVTs. My wife drives an Accord with a CVT and for my personal piece of mind, I have done a drain and Fill at 40k, 50k, and I'm now due to do it again as she just hit 60k. I'll probably wait another 20k and do fluid drain and fills at 80k, 90k and 100k. It's pretty simple. Hardest part is getting the car level on 4 jack stands. No getting it up to temp. Just drain, fill, warm up and take fill bolt out to drain the excess.

I'll probably do the same on the 4Runner but will start at 30k and do it 4 times to 70k. Since I only drive it 6k miles a year, that will be 10 years from now. Maybe I'll report back on how its doing then. Haha.

I'm sure it's overkill but when I had my 06, I never changed it in the 164k I drove that one for. Never had a tranny problem.

Diffs are a different story. We lost a bearing in my wife's 03 4Runner at 118k because I never changed the rear diff fluid. That was a hard $2.5k lesson learned.