Auto trans fluid & filter change + valve body torque to spec

I'm planning on draining and refilling the automatic transmission in my 92 Super Custom Limited. Looks like you just drop the pan in order to drain and then refill through the dipstick tube. While I'm in there I'd like to change the filter/strainer and torque the valve body bolts to spec (gotta look that up). Looks like there's a gasket under the filter as well. I've ordered the following parts:

AUTO TRANS PAN GASKET 35168-22011
FILTER/STRAINER 35303-30060
FILTER/STRAINER GASKET 35339-28030

I searched but haven't seen any posts about this process. Has anyone done it and if so do you have any tips?

One additional question re: ATF. I purchased 4 quarts of O'reilly brand Dexron VI Full Synthetic ATF. The label on the back of the bottle reads: "This fluid is suitable for use where DEXRON II, DEXRON III, JASO M315(1A), Toyota WS, Toyota T-IV fluids are recommended." My van recommends Dexron II and I've heard that Dexron III techologically supercedes Dexron II. The bottle's message seems to be state pretty definitively that this Dexron VI will work fine. Does anyone run Dex VI in their van? What kind of ATF do you use?

I posted a walkthrough on the forum on dropping the pan and changing the screen, same transmission as you,  A45DE. I've been using Dex/Merc which is equivalent to Dexron III.

https://hiace-super-custom.forumotion.com/t3533-transmission-oil-pan-gasket-strainer-replacement

I avoided Dexron VI after reading a huge amount about the subject and instead went for some synthetic III. You can get it cheap in big containers, something you'll appreciate if following my recipe below...

IIRC there was something different about VI that I didn't trust.
Also wear gloves, ATF 'isn't good' for your skin/body. Probably best to avoid the vapours too much as well.

BTW 'flushing' auto fluid is quite a risk prone exercise if the old fluid is not in good condition, because of the dirt left sitting around in the box and torque converter. Flushing is a well known 'technique' to wreck a transmission completely, but a partial pan change also has pretty much the same action IMO.
There are two theories:

1. The dirt comes off all at once and blocks stuff up
2. The dirt used to help the old oil grip the plates

My own favoured theory is 1, because new ATF has a very (very) strong cleaning action like nothing else, it's quite aggressive. After 10 miles on a partial (3L) change it can come out black and smelly - stuff you don't want to leave in your box for the next 100,000 miles LOL.

So my own opinion is:
1. Do the change
2. Only drive one short warm-up cycle around the block.
3. Change it again.
4. If the old stuff was dirty (not looking like new) drive twice as far as before and goto step 3.

Until it's clear. Buy new copper sealing washers, heat them red-hot to re-anneal if re-using.

This strategy gets the old dirt safely out of the box as soon as practically possible and is in my view the least risky way because you are actually checking the fluid each time.

Bear in mind your new filter will take a deluge of dirt if it was dirty before, I didn't bother changing mine as it was a gauze so I decided the dirt was too fine to clog it up.

BTW my transmission still works fine if that's a comfort, but I am on oil change #4 and will change again when convenient just because it's always good to be sure

Dexron VI is a low viscosity trans fluid, Dexron II & III are high viscosity. The VI is not suitable.

The idea that flushing a trans can harm it is basically an old wives tale. Quite literally. It was trueish for old transmission designs - pre 70’s ish - but it is nonsense for modern cars (50ish or younger years old) that seems to have been perpetuated ad infinitum in this day of Google, Forums & “experts” with a camera and a YT login. Unfortunately cause and effect gets confused and a flush is blamed for failures from a lack of previous maintenance.

The advice to do a double change is good and I’d leave a filter change (or clean of the gauze type) until the second one. Not sure about the 92 but for the later Aisin boxes in the ‘95 I think Toyota (from memory) specify 60Km for the change interval, but that change is a drain and refill of the trans sump of only just under 2L of a total capacity of 8.2L.

There’s nothing magical about a trans fluid flush that’s going to “dislodge” supposed crud. If you have “dirt” in your trans the only place it came from is clutch material, seal material or metal, which will end up in the filter or the pan and you have serious wear or failure already occurring. Trans fluid is not oil, it’s not sludging up but it will deteriorate especially if run hot. Best thing to do for any trans no matter the history is a fluid change. WITH THE CORRECT FLUID.

On a tangent:
The “correct fluid” seems to be a tricky thing. I’ll never use either Penrite or Nulon trans fluids again. They were both caught out claiming a trans fluid was suitable for LV applications. Turned out they weren’t. Penrite were prosecuted in Aussie and had to publicly notify a “recall and fix” for consumers with damaged ZF6HP transmissions. (This was more than 5 years ago. They had the recall notice on their site but it’s no longer there. Think I saved it!) Have never trusted any of their oil marketing since. I have a 20L of Nulon full syn trans fluid in my garage that claims on the side to be suitable for BMW & ZF Lifeguard 6 spec (& Shell 1375.4?) Funny thing is, their website removed that spec and ditto the new packaging for that identical fluid. Dodgy bstrds.

What the OP above notes about the claims of suitability of the Dexron VI sounds like the exact same BS.

Dead right mate the drain plug will only release 2 ltrs of the 8 in there there is a good description on the 4x4 sights how to flush the system compleatly (forgot which one) and there is no filter just a mesh screen in the sump on the hiace auto box, pig of a job to clean it no need to replace just clean with brake cleaner. Done one never again I am lazy just do a few drain 2ltrs and replace till fluid is correct colour.

I get almost exactly 3 litres from my 2WD A340E transmission from the pan.

1. My trans fluid was just a bit brown when it came out.
2. After a few miles I changed it again and it came out black.
3. Then after a few more miles it came out blackish
4. Then it came out not too bad.
- The last dipstick test it looked quite clean and red.

I'll change it again before another long journey as it's cheap I'm happier when it's the right colour
I would definitely stick to II or III if the dipstick says DXII on it though.