Transmission Fluid Drain and Fill Question:

[luke87gt]

Hi all,

I've spent the last hour reading about drain n fill on the 4th gen T4R.

I have one question that I'm not entirely clear on.

Once you fill the transmission after the drain, and you have the transmission at the appropriate temperature... Do you open the overflow with the car off or with it on in Park?

Can someone confirm?

Also, is there just a drain and a full plug (2)? Or is there a drain, fill, and overflow plug (3)

Thank you.

 

[AuSeeker]

Engine running, 3 plugs, drain and level check plugs on the bottom of the pan, fill plug on the passenger's side of the transmission.

 

[TowMeOut]

If you're gonna do it, skip the "drain and fill". Dumping the fluid from the pan only replaces something like 1/3 or less of the fluid. The rest is stuck in the torque converter.

There are several threads about replacing the fluid through the transmission cooler lines. That was the route I went. It took a little "redneck engineering" to rig up a reservoir but worked like a champ. I swapped the fluid in the wife's van the following weekend.

 

[Montego Murph]

Is there any reason why manufacturers never installed a drain plug for the torque converter? It seems like that would make the drain-n-fill procedure more complete. Refilling it might be interesting though.

 

[luke87gt]

Thank you for the reply everyone.

Well, I ended up doing 4 drain and fills on my 2006 4Runner V6 2WD with 140K miles. I don't believe it was ever replaced.

The first drain I did with the car cold. I first opened up the overflow bolt and just about 0.5 quart came out. Next I opened up the drain and another 2.0 quarts came out. So the total amount of fluid from a drain was 2.5 quarts.

I was surprised to see 0.5 quarts of fluid come out of the overflow. I didn't expect that. But then again I'm not sure if less would have come out (or none at all) if the car was warm and running and circulating through the system, as that's how you are supposed to check the fluid overflow from what I understand.

The old fluid was much darker than the fresh WS fluid. By my calculations, I have this much new fluid (I'm assuming 12 quart capacity with 2 quarts fresh fluid added at each D&F):

1st D&F: 2 quarts / 12 quarts = 17% new, 83% old.
2nd D&F: 31% new, 69% old
3rd D&F: 42% new, 58% old
4th D&F: 52% new, 48% old

Thanks again for all the help everyone.

Luke

 

[luke87gt]

Sure enough, with the engine running and trans fluid circulating through the system, you need more fluid (0.5 quart or so) before you see something coming out of the overflow compared with the car off.

I know some people check the fluid with the car off which would result in about 0.5 quart low.

 

[AuSeeker]

Thank you for the reply everyone.

Well, I ended up doing 4 drain and fills on my 2006 4Runner V6 2WD with 140K miles. I don't believe it was ever replaced.

The first drain I did with the car cold. I first opened up the overflow bolt and just about 0.5 quart came out. Next I opened up the drain and another 2.0 quarts came out. So the total amount of fluid from a drain was 2.5 quarts.

I was surprised to see 0.5 quarts of fluid come out of the overflow. I didn't expect that. But then again I'm not sure if less would have come out (or none at all) if the car was warm and running and circulating through the system, as that's how you are supposed to check the fluid overflow from what I understand.

The old fluid was much darker than the fresh WS fluid. By my calculations, I have this much new fluid (I'm assuming 12 quart capacity with 2 quarts fresh fluid added at each D&F):

1st D&F: 2 quarts / 12 quarts = 17% new, 83% old.
2nd D&F: 31% new, 69% old
3rd D&F: 42% new, 58% old
4th D&F: 52% new, 48% old

Thanks again for all the help everyone.

Luke

I truely don't understand why you just didn't do a complete fluid exchange, if you would have just done the process via the cooling lines with another 4 quarts, maybe 5 you could have 100% new fluid in there instead of using 8 quarts to get around 50% new fluid comtaminated with old fluid. :noidea:

 

[luke87gt]

I truely don't understand why you just didn't do a complete fluid exchange, if you would have just done the process via the cooling lines with another 4 quarts, maybe 5 you could have 100% new fluid in there instead of using 8 quarts to get around 50% new fluid comtaminated with old fluid. :noidea:

Ever since I've been tinkering with cars (20yrs) I remember the debates people have in whether or not it's a good idea to do a complete flush on a high mileage older transmission. I've read enough on the topic that I prefer to tread cautiously by avoiding the complete flushes on my old cars.

If the transmission has had regular interval transmission flushes from the beginning, then I have no issue flushing. Otherwise, if I'm doing the first trans service at 150K or 200K, then drain and fill. You get some of the benefits, but you don't completely change the environment by 100% eliminating the abrasive material in your worn transmission.

https://www.pro-max.com/can-changing-transmission-fluid-damage-transmission/

I'm sure this debate will go on forever

 

[AuSeeker]

Ever since I've been tinkering with cars (20yrs) I remember the debates people have in whether or not it's a good idea to do a complete flush on a high mileage older transmission. I've read enough on the topic that I prefer to tread cautiously by avoiding the complete flushes on my old cars.

If the transmission has had regular interval transmission flushes from the beginning, then I have no issue flushing. Otherwise, if I'm doing the first trans service at 150K or 200K, then drain and fill. You get some of the benefits, but you don't completely change the environment by 100% eliminating the abrasive material in your worn transmission.

https://www.pro-max.com/can-changing-transmission-fluid-damage-transmission/

I'm sure this debate will go on forever

Doing a complete fluid exchange is not a "flush" that could indeed loosen sludge/contaminates that may clog something within the transmission.

A flush is removing the old fluid under high pressure and a then using a cleaning/flushing solution again under high pressure, which can indeed be an issue on high mileage transmissions, especially of older design, but not nearly as much an issue if at all on these modern design transmissions using advanced fluids, but I still wouldn't do it on my transmission with high mileage.

But doing a complete fluid replacement via the cooling lines is only exposing the transmission to normal pressures and no sludge will get dislodge, they will however be very very slowly dissolved by the new fluid.

I'm not saying you did the wrong thing that is up to you, I having well over 45 years experience just don't understand why one would do it only part way with how far advanced these transmissons and modern fluids are, we are not talking about a 1957 Chevy with a hydramatic transmission, which is still actually a very good transmission design, the design is still used in drag racing but a bit modified.

 

[k3v11n]

Ever since I've been tinkering with cars (20yrs) I remember the debates people have in whether or not it's a good idea to do a complete flush on a high mileage older transmission. I've read enough on the topic that I prefer to tread cautiously by avoiding the complete flushes on my old cars.

If the transmission has had regular interval transmission flushes from the beginning, then I have no issue flushing. Otherwise, if I'm doing the first trans service at 150K or 200K, then drain and fill. You get some of the benefits, but you don't completely change the environment by 100% eliminating the abrasive material in your worn transmission.

https://www.pro-max.com/can-changing-transmission-fluid-damage-transmission/

I'm sure this debate will go on forever

Lol. I'm opposite. 168k miles on original trans (04 V6) and was told not to do any flush or drain and refill. No record of the trans ever being serviced.

Sent from my SM-G930V using Tapatalk

 

[BlackWorksInc]

Is there any reason why manufacturers never installed a drain plug for the torque converter? It seems like that would make the drain-n-fill procedure more complete. Refilling it might be interesting though.

No real way to do so because of the maze-like construction of the TC and how it works, it'd take for ever to drain even if it did have a drain plug.

I truely don't understand why you just didn't do a complete fluid exchange, if you would have just done the process via the cooling lines with another 4 quarts, maybe 5 you could have 100% new fluid in there instead of using 8 quarts to get around 50% new fluid comtaminated with old fluid. :noidea:

I don't disagree with doing a flush through the lines as long as you check the fluid level after you do so, the bigger issue with doing it that way is mainly two things (well the first isn't really an issue, more of a clarification to be fair):

-You don't replace 100% of the fluid, nor does it guarantee that the new fluid is 100% clean either. Between the small pockets of fluid in nooks/crannies, and low pressure zones; as well as the sediment in the transmission the fluid, you'll never get 100% of the fluid out unless you tear it down. But you'll probably get a slightly better percentage than 3-4 drain & fills.

-Usually by the time you run 9~12qts of fresh fluid to get the best possible flush of the system the vehicle will be at temperature (which is good if you've planned ahead) or it will be over temperature (now you're waiting hours for it to cool down, making your service far longer than it has to be).

In the end it doesn't really matter either way, it's not about getting 100% of the old fluid out and 100% of the new fluid in; if it really mattered/needed to be done you'd be tearing down the transmission and cleaning it out. It's about replenishing the additive packages in the fluid and refreshing as much of the fluid as possible, much in the same way you do oil changes and cooling system services.

That being said, either method works well; usually after about 9~12qts you've flushed out enough of the old fluid that it's close enough to new anyways and smaller drain & fills tend to be a bit easier to manage without going over temp assuming you started cold and it's not excessively warm outside already.

Post Note-

To the OP, you did check the temperature with the vehicle running within the specified fluid range yes?

 

[luke87gt]

To the OP, you did check the temperature with the vehicle running within the specified fluid range yes?

I did, I used the wire jumper on the OBDII connector and got the temp within the appropriate range before I opened up the overflow and set the appropriate fluid level, hooray!

 

[CredeCo76]

Drain or flush

New T4R owner here. 2006 ltd,4.7. 128,000 miles.
Thanks for this thread.
I can't verify if the trans has ever been serviced in any way. I've watched many videos of drain & Fill,filter change, and repeated drain & fill to empty TC.
Been reading different threads here.

I stopped at two different dealers to see what they do and how much$.
One said they only do flushes ($260.00), never drain and fill.

The other said they usually service every 60,000 miles. But with my mileage and unknown history, if he were me with the same situation. he wouldn't do anything and just drive it.

So I'm confused, I bought this because of the dependability and longevity with routine maintenance. The trans shifts smoothly and seems to have no problems.

Any consensus or experience with buying a high mileage TR4 and unknown trans maintenance would be appreciated.
Thanks again.

 

[AuSeeker]

New T4R owner here. 2006 ltd,4.7. 128,000 miles.
Thanks for this thread.
I can't verify if the trans has ever been serviced in any way. I've watched many videos of drain & Fill,filter change, and repeated drain & fill to empty TC.
Been reading different threads here.

I stopped at two different dealers to see what they do and how much$.
One said they only do flushes ($260.00), never drain and fill.

The other said they usually service every 60,000 miles. But with my mileage and unknown history, if he were me with the same situation. he wouldn't do anything and just drive it.

So I'm confused, I bought this because of the dependability and longevity with routine maintenance. The trans shifts smoothly and seems to have no problems.

Any consensus or experience with buying a high mileage TR4 and unknown trans maintenance would be appreciated.
Thanks again.

Most if not all of us who own these 4th Gen T4Rs don't consider 128,000 to be high mileage, these vehicles will go to 300,000 miles easily and most will still keep going way beyond that, and there are many here who have done the transmission flush for the first time at well over 200,000 miles and no issue, most experience much better performance, if I were you I would not hesitate to do the flush.

 

[2003-4x4runner]

Flush the Transmission.

New T4R owner here. 2006 ltd,4.7. 128,000 miles.
Thanks for this thread.
I can't verify if the trans has ever been serviced in any way. I've watched many videos of drain & Fill,filter change, and repeated drain & fill to empty TC.
Been reading different threads here.

I stopped at two different dealers to see what they do and how much$.
One said they only do flushes ($260.00), never drain and fill.

The other said they usually service every 60,000 miles. But with my mileage and unknown history, if he were me with the same situation. he wouldn't do anything and just drive it.

So I'm confused, I bought this because of the dependability and longevity with routine maintenance. The trans shifts smoothly and seems to have no problems.

Any consensus or experience with buying a high mileage TR4 and unknown trans maintenance would be appreciated.
Thanks again.

Had my transmission flushed at the dealer at 120k miles and again at 230k miles at the dealer again. They had a service special of $200 at the time so it wasn't that expensive. I'm at 236k now with no issues.

Just take it to the dealer and have them do it. It's quick, easy and you wont have to deal with the old transmission fluid.