Transmission oil drain and flush

[quatin]

Transmission oil drain and fill

I see a lot of threads recommending only a drain and flush for the transmission.
Just to clear things up, do you drain from the oil pan? Do you do this only once?

I used a hand pump and pumped out 2 qts of transmission oil from the dip stick tube and poured in Dextron III oil from the same tube. The spec sheet says it contains 2.1 qts in the oil pan, however it also says the transmission holds 10 qts of oil total. This means I only replaced 20% of the transmission oil. Should I do multiple drain and fills? How much should I replace?

For background purposes, I have a 2000 4runner with 76k on it and I'm just trying to do some preventative maintenance. I believe a flush/fill was done at 60k by a shop. I only realized (remembered) that I may have done this when the old fluid that came out was just dark red.

 

[IanB]

To start off, you're confusing the 2 options available to you:

-flush - when you hook the tranny to a machine that forces the old fluid out, and replaces with new, high pressure flush that loosens up deposits in the tranny and hopefully gets them out of the system. Not recommended for old tranny's as the deposits might be left inside, and can clog passages, and cause problems down the road.

-drain and fill - drain fluid from the pan drain bolt, measure what came out, and replace, top up to proper level. This will not change all the fluid, so if you have a tranny with old burnt fluid, or unknown maintenence history, do a couple drain/fills over the period of a few weeks. This will replace the majority of the old fluid, without risking blowing out any seals with high pressure flushes.

I'm an advocate of the drain/fill method, I've done 3 or 4 since I picked up my truck, and the fluid is now clear and red, not cloudy and brown/black like before. Now that I have the fluid clean, I plan on doing a drain/fill every year going forward, unless the fluid looks burnt, and I'll do more as required.

 

[badattitude]

Make sure you have 5 quarts of oil on hand when you drian and fill. Five quarts of fluid came out of my 1999. I know my buddies Tacoma only gave up 2 quarts when drained. So hard to say for sure how much you'll get out but you need to have plenty of new fluid on-hand.

 

[quatin]

To start off, you're confusing the 2 options available to you:

-flush - when you hook the tranny to a machine that forces the old fluid out, and replaces with new, high pressure flush that loosens up deposits in the tranny and hopefully gets them out of the system. Not recommended for old tranny's as the deposits might be left inside, and can clog passages, and cause problems down the road.

-drain and fill - drain fluid from the pan drain bolt, measure what came out, and replace, top up to proper level. This will not change all the fluid, so if you have a tranny with old burnt fluid, or unknown maintenence history, do a couple drain/fills over the period of a few weeks. This will replace the majority of the old fluid, without risking blowing out any seals with high pressure flushes.

I'm an advocate of the drain/fill method, I've done 3 or 4 since I picked up my truck, and the fluid is now clear and red, not cloudy and brown/black like before. Now that I have the fluid clean, I plan on doing a drain/fill every year going forward, unless the fluid looks burnt, and I'll do more as required.

I think I had a flush and fill done at 60k by a shop. The oil is a dark red, so it's probably unnecessary to change at the moment. However, for future reference. Do I roughly want to replace all of the old transmission fluid? I read some conjecture to replace only half of the fluid every 30k miles. He said that replacing all of the transmission fluid would add a lot of detergent all at once that could loosen up deposits.

 

[quatin]

Make sure you have 5 quarts of oil on hand when you drian and fill. Five quarts of fluid came out of my 1999. I know my buddies Tacoma only gave up 2 quarts when drained. So hard to say for sure how much you'll get out but you need to have plenty of new fluid on-hand.

I bought 2 gallons of Pennzoil Dextrol III just in case. However, I did check the repair manual and it said the oil pan contains only 2.1 quarts, which is about how much I pumped out. I may use the rest of it to flush and fill the power steering fluid.

 

[techno]

Measuring the amount of replacement fluid is a good rough guide, but make sure you read the dipstick too. The hot range is the important one. The cold indication area should be used as a reference only.
To perform the hot check properly, make sure the engine is at full operating temp for several minutes. Immediately prior to checking the dipstick, shift the transmission from P to L and back again, pausing for about 1 second in each position.

 

[quatin]

Measuring the amount of replacement fluid is a good rough guide, but make sure you read the dipstick too. The hot range is the important one. The cold indication area should be used as a reference only.
To perform the hot check properly, make sure the engine is at full operating temp for several minutes. Immediately prior to checking the dipstick, shift the transmission from P to L and back again, pausing for about 1 second in each position.

Yup, did that too. It was pretty confusing for a while, until I realized my driveway was slanted. I even drove around at higher gears before doing a final fluid level check. The only thing that I'm confused on is how much transmission fluid I should replace.

 

[IanB]

Yup, did that too. It was pretty confusing for a while, until I realized my driveway was slanted. I even drove around at higher gears before doing a final fluid level check. The only thing that I'm confused on is how much transmission fluid I should replace.

Replace whatever drains out, and repeat until you are satisfied that most/enough of the old fluid has been replaced. This method mixes the old and the new fluid, so every subsequent time you drain/fill, you are draining out some of the new fluid as well. There is no need to get 100% of the old fluid out, just enough that the fluid in the tranny is in good shape, and up to the task. Then just do yearly drain/fills after that point to keep the fluid freshened up.

 

[techno]

.. It was pretty confusing for a while, until I realized my driveway was slanted....

haha, yep, that's pretty important. I had the same issue once.

 

[Pikeman]

Ok here is my opinion. Drain from the drain bolt option one- I just did this Friday and got roughly 5 quarts out, vehicle/ fluid should be warm. The rest of the fluid is left in the Torque Converter that is why it doesnt drain. Replacing half is the best way to go and pretty easy if using the drain bolt. If your trans has not been serviced for a while I would drop the pan and replace the filter. Both dropping the pan and using the drain plug methods would get you about 50% replacement of 5 quarts.

 

[RunninOnBlue]

If you choose to drop the pan to clean the filter, I recommend using a rubber gasket instead of the RTV gasket stuff. The rubber gasket is cheap, doesn't need to cure, and saves me about 30 minutes of getting the pan off and cleaning all the old RTV crap off.

I use this one Buy Felpro Automatic Transmission Gasket TOS 18685 at Advance Auto Parts

 

[quatin]

Ok here is my opinion. Drain from the drain bolt option one- I just did this Friday and got roughly 5 quarts out, vehicle/ fluid should be warm. The rest of the fluid is left in the Torque Converter that is why it doesnt drain. Replacing half is the best way to go and pretty easy if using the drain bolt. If your trans has not been serviced for a while I would drop the pan and replace the filter. Both dropping the pan and using the drain plug methods would get you about 50% replacement of 5 quarts.

I think I had a transmission fluid flush at a Jiffy Lubes or something at 60k. Would that have involved removing the pan and replacing the filters?

 

[Pikeman]

Usually a fluid flush is just that, they hook up to your lines and pump fluid through the system. If it was called a Transmission service then there is a possibility they dropped the pan and cleaned or replaced the filter. Our filters are just metal mesh and can be cleaned and reinstalled but there are some of us that suggest spending the 15-20 for the new one.

 

[Nunyabiz]

What I did on mine was to replace the fluid which had about 65,000 miles on it, still looked good.
I had them drop the pan since the truck was new to me with 157xxx miles on it I wanted to visually see what the trans looked like.
Looked like brand new inside and the "screen" (there is no filter)looked like new also.
The 4 magnets on the bottom of the pan had almost nothing on them, so it was nice to do just for the peace of mind.

That drained about 4qts.

Put the pan back on and put the 4 qts in then took the trans fluid line off the radiator or external cooler if you have one and proceeded to drain the rest of the fluid from the torque converter about 1-2 qts at a time, drain, replace, drain replace.
make sure you toggle through all the gears also.
I think it is closer to 12 qts total.

You can also take to what ever place nearest you that has a T Tech machine, you will need about 15-16 quarts, they hook it up to the cooler lines and run the truck and it takes the old out and puts the new in using the transmission pump itself so there is no more pressure than there is when you are running normal and you should get about 95% of it out and changed.

Doing a drain and fill is virtually worthless as far as I am concerned.

Changing 4 quarts out of 12 is at best a 1/3rd new added to 2/3 old.

I put in Amsoil Synthetic to replace the standard trans fluid that had 65K on it.

 

[Phx994Runner]

Put the pan back on and put the 4 qts in then took the trans fluid line off the radiator or external cooler if you have one and proceeded to drain the rest of the fluid from the torque converter about 1-2 qts at a time, drain, replace, drain replace.
make sure you toggle through all the gears also.
I think it is closer to 12 qts total.

Which line specifically do you drain from? I also have an external B&M cooler - I would imagine the output side/hose of the cooler that returns the fluid back to the transmission? I'm not sure which is the input and output hoses on the transmission...

I just did this over the weekend, actually, with my '99 Land Cruiser but someone had great pics already with the correct hose to disconnect

Thanks.

 

[Nunyabiz]

I honestly don't remember, the mechanic I took it to did it, I was there right next to him and in fact helped with it but really did not pay attention to which line he removed. I was inside the truck most of the time, turning it over and going through the gears.
Seems as though it was the one leading to the external trans cooler but I cant say for sure.

I wish I had a garage so I could do this myself, however I live in a Town home with no garage of any kind just a parking spot and anything more than just checking your oil and maybe adding a qt. they frown on.
Can not do any work on vehicles in the parking lot other than washing it.

I think if I do it again I will probably take it to a T-Tech machine, it doesn't do a "flush" it just replaces the fluid using the trans pump.

 

[LittleCaesar]

Looking from the front of the 4runner, at the two metal lines coming from the transmission, the one closest to the right front tire is the output line, the other is the return line.

12qts of Amsoil ATF or Castrol Import Vehicle ATF should work well for ya for a drain and fill.

 

[Phx994Runner]

ok, good info.

Thinking about it, perhaps it doesn't really matter which line I remove to drain, either way it'll drain being pushed out by the pump. I just wonder if one would make a bigger mess than the other...?

Does that make sense - removing either hose would do the job?

 

[IanB]

ok, good info.

Thinking about it, perhaps it doesn't really matter which line I remove to drain, either way it'll drain being pushed out by the pump. I just wonder if one would make a bigger mess than the other...?

Does that make sense - removing either hose would do the job?

Pulling the line that feeds the cooler will allow you to direct where the fluid gets pumped out to bu aiming the hose, removing the other line will have fluid pumping out of the cooler exit, and you have no control over where that goes, just do your best to catch it kind of thing. Either will get the job done.

 

[mongo161]

I just did a drain and fill on my 97, T4R, SR5 and refilled with 5.2 quarts of Valvoline Mercon V instead of the Dexron/Mercon ATF that is sold. The Valvoline Mercon V is forward compatible with DexronIII and Mercon. IMO.....Dexron/Mercon are the same fluids only GM uses the term Dexron while Ford uses the term Mercon. Whatever, make sure you don't fill with Dexron VI or any of the other Mercon fluids like LV.

So far the tranny is purring away. My prior fill, 4 years ago, was 100% Mobil 1, ATF added via fluid exchange. With Mobil 1 alone, the transmission ran very rough until I added 14 ounces of LubeGard Red....which helped smooth it out. One ounce of LubeGard red was added to the Mobil 1 for each quart of ATF.

So now I'm running a blend of MerconV and the older Mobil 1 with the LubeGard additive in my trans with external cooler. From here on out I'll do a drain a fill yearly with MerconV.