Transmission Service Interval - Aisin Recommendations

This is interesting, I did not realize it was this often myself, I thought it was 30k miles. Aisin recommends a drain and refill every 20,000 km / 2 years. That’s roughly every 12.5k miles! Lol, and Toyota says every 60k miles.

I do understand the logic, if you drain the pan and replace 3 of the 9 - 12 or so quarts every 12k the fluid is kept fresh and is ideal for longevity. So who is right? Toyota or the transmission manufacturer? Which company has the most interest in promoting longevity? Aisin, obviously. Services intervals in our manuals are BS. Marketing takes priority over engineering.

 

I plan on switching to a full synthetic fluid very soon and I’ll do a drain and refill every 20k. I’m also going to do my gear fluid as well, just start doing it myself.

 

Sounds like a blanket statement.
So we are group all transmission and their operating conditions in to one?

Ok, I guess?

 

No, but the logic is clear. If you continually introduce new fluid into the system you maintain ideal operating environment. Maybe it seems excessive and it may be. If UOA’s show the fluid breaks down by 30k miles and we all know WS is not synthetic fluid I agree with the logic. I do know on my Lexus forums guys getting tremendous mileage out of the units changed the fluid often, not all at once either. Regular drain and refill is the best way to maintain these units.

 

Did my transmission and differential’s front and back at 80000.

 

Possibly. I can’t see how changing it that often will hurt it.
I’m just lazy, and I figure the engine (timing components) or frame will need replaced before the transmission, if I do what Toyota says.

 

Your transmission is much more likely to fail before the engine. The lack of maintenance is why. Toyota service intervals are designed to get through the warranty period. Nothing more.

 

Maybe.
Oddly enough it seems like a bigger expense related to the engine or frame usually decommissions the truck first. At least on one 2nd Gen trucks.

 

are you inquiring or lecturing?

 

He is telling us….
Not asking.

The advice isn’t “bad”.
I’m just not one to follow it.
12k seems excessive to me?

 

All the plugs would be stripped and damaged if you did it that often.

60,000 miles is fine. Shorter if you abuse it.

 

The transmission manufacturer is likely not the ‘expert’ they’re being made out to be in this thread. Aisin is a contract manufacturer building many components and subassemblies to a specification. They probably even perform certain pre-designed tests for quality control per the spec from the manufacturer. They may have even done the design work required for those components and subassemblies, but again to a customer provided specification. Toyota is their customer and provider of the specifications. They buy components to a specific set of criteria, that I’m certain contains a maintenance interval.

 

So you think Toyota designed the transmission and then went through a huuuuge manufacturing transfer for Aisin to make it how Toyota designed it? I’ll bet dollars to doughnuts Toyota gave Aisin the specs for a transmission to fit the truck (e.g.bolt pattern to block, dimensions, and gear ratios) and they did 99% of the design work to meet what Toyota asked for. They would therefore know what longevity the unit has and how well to maintain it.

 

I've posted this information several times over the years...

What makes you think it's just a drain and fill at 12.5K?

There is an older version of that, where they recommend a certain machine, implying full fluid replacement.

 

FYI...
This transmission is used in several other Toyota vehicles as well as the Isuzu D-Max.

 

Geez. Even on my street class SCCA car (driven hard, but with mechanical empathy) I only cut both the trans and Torsen service intervals in half and went from dino to synthetic.

She's still holding together at 27 years old.

 

Many articles state 30k drain and refill. What I’m saying is I have seen and been advised by very knowledgeable individuals to start the drain and refill process early if you want to get the longest life out of your transmission. I personally don’t recommend flushing. The safest and surest way of extend the life of the unit is to consistently introduce new fluid on a frequent basis. And this was a big discussion when Toyota / Lexus was still calling it a lifetime fluid. Those poor suckers were loosing their units by 150k miles if not earlier but those that started early often saw 450k+ miles.

 

I do a D&F every year, in six months it will be my 4th time. And I use Aisin ATF at a cost of $6. per quart from RockAuto.

 

@gearcruncher time for some of your wisdom!