I want to do the tranny fluid exchange but I don't know what is in there..... (1 Viewer)

[Francis K]

Hi all, just doing maintenance on the truck as I am incredibly cautious with this thing. Oil changed, got everything greased and I want to do the gallon in gallon out of the tranny fluid.

Problem is I don't know what is currently in there, don't know what the previous owner used. Does that mean I should most likely just do a full flush?

Thanks guy

 

[QuackAxel]

i feel like you are over thinking it.... I just did this not to long ago. I bought the correct amount as per specs and it wasn't near enough. Don't remember the quantities. Will be in the FSM.

Also didn't do the gallon for gallon thing. I just drained it, out back what the FSM said it required, and then let it warm up, drive it a few miles and added from there.

 

[SpenserAK]

FSM does spec low for a drain/fill. I always get ~4.5qt out of my 343 and check fluid level every once in a while.

You should be fine to drain/fill with dex/merc. Do it a few times over time if you want, or do a full exchange - but not a power flush, or whatever they call them.

 

[Kernal]

What model 80 series/transmission?

Either way, they all use the same ATF, Dexron II/III compatible fluid.

Been discussed before but it takes around nine drain and fills to change
out most of the old ATF, so easier and cheaper to just do a complete fluid exchange.

If you do just a drain and fill, might help to pour a quart or two of ATF straight through the pan after you drain it and before refilling. That might wash out any debris that got stirred up on the bottom of the pan.

Either way, the new fluid, IME, can stir up/release particles into the fluid so consider adding an inline transmission filter to catch those.

Whatever route you go, be sure to use a new crush washer every time you remove and replace the drain plug. It is too easy to overtighten the drain plug and spin the bung that holds the threads for the plug especially when reusing the old crush washer. Don't gorilla grip the wrench and torque it too tight.

 

[ajax1]

I buy napa dex 3 works for me, my 94 with a442 held more than my a343s in the 95 and 96. If you want to do drain and fill , just drain and let it drain all out, add 4.5 back in go for drive and check

 

[Rusty Marlin]

You don't tell us what year.
My 97' is a 2 qt exchange. I do it every oil change. I found a large Folgers poly coffee tub to be perfect. I measured 2qts of water into it and marked a line. Drain 2 out, pour 2 in. Don't over think it.

 

[Francis K]

Thanks fellas it's a 97 my apologies for neglecting that. I overthink everything with this truck, I treat it like a damn newborn baby....which is not really a good thing.

I was actually planning to do the lower tranny cooler hose funnel and bucket trick....what do you guys think? Just kinda hung up on the procedure if I should run the truck and let it all drain out then fill through the dipstick or to do a gallon at a time, seeing conflicting methods....

 

[Rusty Marlin]

If draining all the fluid under power, you need to drain and fill at the same time. You fill through the radiator port you took the hose off to drain the tranny out of.
It's generally not a good idea to change it all at once as has been mentioned before.

 

[Malleus]

Thanks fellas it's a 97 my apologies for neglecting that. I overthink everything with this truck, I treat it like a damn newborn baby....which is not really a good thing.

I was actually planning to do the lower tranny cooler hose funnel and bucket trick....what do you guys think? Just kinda hung up on the procedure if I should run the truck and let it all drain out then fill through the dipstick or to do a gallon at a time, seeing conflicting methods....

You'll be wasting money if you don't replace all the fluid at once. There is no way to ensure that all the fluid has been replaced, swapping one quart in for one quart out, without using a lot of oil. Think about trying to clean a swimming pool this way and you'll see how much fluid you'll need without doing the math and making a lot of assumptions along the way.

It's really not that hard. Buy 4 gallons of ATF and have the transmission pump it out.

You'll need to get the fluid hot, or at least warm. I let mine idle for a half hour or so and then pull the plug and let it drain into a graduated container, in a medium mortar tub, on an oil drain pan/sheet (yes, it's that messy). You'll only get 2+ quarts this way, unless you allow it to drain overnight. I've been able to get 8 quarts out at most. The rest has to by pumped out by the transmission pump; it'll be in the lines and cooler and torque converter, so when you add the 2 gallons back initially, it'll go into the case.

You can get a generous 3.25 gallons in before you need to check the fluid level. Be sure to use a graduated container to catch the old fluid in so you'll know how much to add. It's better to err on the side of low oil than too much, when you're filling. Draining oil out is a messy job and you always lose too much. Get the system within a quart of full and go through the gears manually, 2-3 times is sufficient. Then check the fluid level.

 

[REKCUT]

Find a shop that has a BG fluid exchange system. American Toyota used to do this but not all Toyota dealers. They plug you up like your on a blood transfusion and roll in new while the old filters out. Not that expensive and gets all new fluid for your truck

 

[Malleus]

If draining all the fluid under power, you need to drain and fill at the same time. You fill through the radiator port you took the hose off to drain the tranny out of.
It's generally not a good idea to change it all at once as has been mentioned before.

I've never done it this way. I drain and fill the same way on the 80 and 100 series:
Drain all the oil out of the case that'll come out,
Replace the case drain plug, with a new crush washer,
Pull the cooler supply line off the cooler and place it into a graduated container (I use a gallon water//milk jug with Sharpy marks on the side), in a medium mortar tub,
Pull the ATF dipstick and replace with an ATF funnel,
Start the engine and pour into the funnel as much fluid as the case drained out, plus whatever the transmission pump ejected into the cooler line, which went into the jug.

Check the fluid level, after running through the gears manually. The whole process took me 20 minutes the last time I did it, not counting the overnight draining. And I saved the EPA DIY fee for disposal and the charge to have someone connect a machine that did the same thing the transmission pump does.

FWIW, there will be some residual used ATF in the system, but it won't be much and nothing short of disassemble will completely clean it anyway.

 

[WarDamnEagle]

Find a shop that has a BG fluid exchange system. American Toyota used to do this but not all Toyota dealers. They plug you up like your on a blood transfusion and roll in new while the old filters out. Not that expensive and gets all new fluid for your truck

This. My '97 had 114k on it when I bought it in 2007 (IIRC). I had the transmission fluid changed with Amsoil Universal ATF at some point early on; no cleaning agents, conditioners, etc....just the ATF. Fast forward about 2 years ago and I had the same service done at around 260k and it was difficult to tell the old fluid from the new. I'm not big on Amsoil but their Universal ATF has impressed me. I will probably never change it again as it doesn't get driven very much.

 

[Kernal]

I also had a fluid exhange/flush done by a BG shop (15+ years ago) on my 96 model, took 16 quarts IIRC. Only concern I had then (and now) is how often anyone cleans out the tank before they pour in the new fluid or change the filter on the machine??

Now I'd just do it myself as mentioned above.

 

[WarDamnEagle]

I also had a fluid exhange/flush done by a BG shop (15+ years ago) on my 96 model, took 16 quarts IIRC. Only concern I had then (and now) is how often anyone cleans out the tank before they pour in the new fluid or change the filter on the machine??

Now I'd just do it myself as mentioned above.

Why would you need a filter on the machine? The transmission does the pumping and the machine is on the input side only with the new fluid. At most you might get some minor contamination from the previous "new" fluid. FWIW, the last shop that did mine let me stand there while they did the service and their machine looked very clean.

 

[CharlieS]

I've never done it this way. I drain and fill the same way on the 80 and 100 series:
Drain all the oil out of the case that'll come out,
Replace the case drain plug, with a new crush washer,
Pull the cooler supply line off the cooler and place it into a graduated container (I use a gallon water//milk jug with Sharpy marks on the side), in a medium mortar tub,
Pull the ATF dipstick and replace with an ATF funnel,
Start the engine and pour into the funnel as much fluid as the case drained out, plus whatever the transmission pump ejected into the cooler line, which went into the jug.

Check the fluid level, after running through the gears manually. The whole process took me 20 minutes the last time I did it, not counting the overnight draining. And I saved the EPA DIY fee for disposal and the charge to have someone connect a machine that did the same thing the transmission pump does.

FWIW, there will be some residual used ATF in the system, but it won't be much and nothing short of disassemble will completely clean it anyway.

@Malleus do you recall roughly how much fluid you have to replace when you service the transmission? I want to do this using your technique, but want to pick up a sufficient quantity of ATF in advance.

 

[BILT4ME]

@Malleus do you recall roughly how much fluid you have to replace when you service the transmission? I want to do this using your technique, but want to pick up a sufficient quantity of ATF in advance.

He mentions a couple posts ahead that he bought 4 gallons.

I do 5 gallons on mine. 20 Qt = 5 galllons.

 

[CharlieS]

Thank you. Apologies for missing that and asking a question that had already been addressed. Maybe I'll just buy a 5 gallon pail. Thanks again!

 

[Malleus]

@Malleus do you recall roughly how much fluid you have to replace when you service the transmission? I want to do this using your technique, but want to pick up a sufficient quantity of ATF in advance.

3 gallons (FSM says 11.6 quarts); I have three 80s so I bought more than I needed for one, because I knew it would be used. And I have a 2000 LX470 that has its transmission on the bench. I'm actually several gallons short.

Capacity you're interested in is "dry fill", because you are replacing all of it. Drain and refill is the pan volume. I don't really know why there is a drain plug in the transmission pan. It's useless. The fill tube is another story.

 

[Malleus]

@CharlieS
I said above that I got 3.25 quarts in before I started checking it. I should have said I was using the last quart to flush the case. After I put in 3 gallons, because I had a helper, I had the transmission run through all gears, foot on brake because I was at the bumper, several times. This was to get the fluid into and out of the spool valve passages. This is an expensive way to clean that area, but the only way to really get it clean is to flush it with kerosene (as per the unit repair manual), and you can't do that while it's running.

Don't ever try to flush an automatic transmission with cleaning solvent unless it's on the bench. The transmission component clearances are designed to use hydraulic fluid to lubricate them, and the fluid has to be under pressure to get where it's supposed to go. Solvents won't work as a substitute.

 

[BILT4ME]

The reason for 5 gallons instead of just 11.6 quarts is to offset and give more dilution to the remaining quart of fluid left in the torque converter. Theoretically, you can never get to 100%swap, but this gets it it extremely close.