2006 Transmission Fluid Service

[2001LC]

So... bubbles apart, a one-step complete drain is then possibe ? Can you run the engine until almost all of the fluid is out ? (converter, hoses, radiator, all except strainer and pan, which then will have to be unbolted in order to get the remaining 3 liters out).

Then after refilling, the system will have some bubbles. Is this a real problem besides having to shift through all gears to remove/purge all bubbles ?

I find this much easier and cleaner than having to mix old with new fluids in several steps. But I don't know whether it is really possible or not.

TIA.

I do complet 12 qt flushes all the time.
After draining pan measuring what comes out very carefully and refilling pan plus 1 qt.
Connecting a hose to return cooler nipple (top RH side of radiator), and run to catch can marked in 1 qt sacraments. I then run engine to pump old out, as I poor in new in. I measure what comes out very carefully. Engine running, transmission pumps out faster than I can add new in. So I stop engine, as need so that I don't run transmission pan low.

Done correctly you'll never run pan low. The only air bubble is a tiny one, from disconnecting & reconnecting return AFT cooler hose. Which is not a problem.

 

[Caaarlo]

I do complet 12 qt flushes all the time.
After draining pan measuring what comes out very carefully and refilling pan plus 1 qt.
Connecting a hose to return cooler nipple (top RH side of radiator), and run to catch can marked in 1 qt sacraments. I then run engine to pump old out, as I poor in new in. I measure what comes out very carefully. Engine running, transmission pumps out faster than I can add new in. So I stop engine, as need so that I don't run transmission pan low.

Done correctly you'll never run pan low. The only air bubble is a tiny one, from disconnecting & reconnecting return AFT cooler hose. Which is not a problem.

Thank you for your prompt reply. I know that procedure... is the more or less the usual one, with multiple drain and fill steps until completion, in order to keep the system free from bubbles and not let the pump work "dry".

But my question was aimed to the possibility of a complete drain, and then a complete fill (not multiple drain and fill steps until completion). Then a final step of fine tuning the pan level with the overflow plug.

Is this possible, besides having to deal with bubbles and purging after the whole process ? Can the pump move all the oil out at once ?

 

[2001LC]

Thank you for your prompt reply. I know that procedure... is the more or less the usual one, with multiple drain and fill steps until completion, in order to keep the system free from bubbles and not let the pump work "dry".

But my question was aimed to the possibility of a complete drain, and then a complete fill (not multiple drain and fill steps until completion). Then a final step of fine tuning the pan level with the overflow plug.

Is this possible, besides having to deal with bubbles and purging after the whole process ? Can the pump move all the oil out at once ?

I'm not talking about drain and fills, repeatedly over time.

I am talking about a complet 12 qt of ATF flush at one time.

You can not just drain all 12 qts. by removing drain plug. That just drains what's in pan plus a little more, depending on how long drain plug out.

These procedures are for automatic transmission. Not manual shift transmission.

 

[Caaarlo]

You can not just drain all 12 qts. by removing drain plug.

I think I am not being clear, probably a language barrier thing.

What I intend to do (and ask whether this is possible or not), is to open the the transmission cooling circuit (by unclamping one of the hoses of course), and let ALL the old fluid to be PUMPED out completely, until the last drop without pouring new fluid in.

Once all fluid gets out, remove the pan and strainer, discard the remaining oil in there, clean the magnets, reassemble, and then refill with 11 liters of WS fluid

My intention is to avoid mixing old fluid and new fluid during the process that you described.

Is this possible, or the pump will run dry and stop pumping way before all fluid goes out ?

 

[2001LC]

No you must add as you pump out. Also never even run much more the 2 qts low, for more than a minute. You can damage any transmission, running it dry or to low.

By draining pan first, than filling again with fresh ATF. The pickup tube is there and this is where the ATF starts, whats is basically a "one way" journey. It's then goes through the system which includes torque convert (which holds a lot). Then on to be cooled. I catch after cooler at last point before heading back to transmission. I see dark old fluid start looking very nice clear red, at around 10 to 12 qts out/in. Which the best we can do.

To drain a transmissions dry, you can leave drain plug out longer and change angle of transmission (raising one end of vehicle). But the most I've gotten was ~5 or 6 qts., IIRC. But the torque convener can't be drain this way, nor can many of the valves and canals inside of transmission..

 

[Battleship]

Is this possible, or the pump will run dry and stop pumping way before all fluid goes out ?

It will run dry after about 1L., (maybe it is 2L, I haven't done it in a long time).

The method @2001LC describes is easy and efficient, with minimal mixing of fluids. Run 14 qts through and consider it a 100% change.

 

[yackowski]

In my experience you can get about a gallon out sitting overnight and pulling the tube with the drain plug and then about 3.5qt per pump session before any bubbles. Just refill with 4 each time and g2g.

 

[Caaarlo]

Ok guys, I really appreciate your help. My 100 already has 330,000km (205,000 miles) and the fluid has never been changed.

If the pump stops doing its job after 2 or 3 liters because (i asume) it starts sucking air from the pan, then what about using vacuum on the line that sends oil to the front radiator in order to get the remaining fluid out ? Will this suck all fluid from the converter ?

Just an idea.

 

[2001LC]

Ok guys, I really appreciate your help. My 100 already has 330,000km (205,000 miles) and the fluid has never been changed.

If the pump stops doing its job after 2 or 3 liters because (i asume) it starts sucking air from the pan, then what about using vacuum on the line that sends oil to the front radiator in order to get the remaining fluid out ? Will this suck all fluid from the converter ?

Just an idea.

Not likely but I really don't no. Torque Converter take special procedure while off vehicle to empty.

If it was me. I'd add back as much as came out plus 1 qt more and put plugs back in. Let it sit a day. Then start and idle for a few minutes. Shift through all gears. Then let it cool down. Why cool down. If configuration of exhaust and transmission, is like a USA market 100 series. The exhaust will burn your arm, getting to fill plug.

Then begin full 12 qt flush all over again. Making sure to be adding as it pumps out. Making sure to stop the engine as pumped out amount, gets ahead of what you can add back in.

 

[Caaarlo]

Well, did the flush yesterday.

Removed the pan, and there were 2 liters. Started the engine for 5 seconds, and turned off. After turning off, an extra 1.5 liter got out of the strainer inlet. Then removed the strainer and got 1.2 more liter. Total 4.7 liters. (about 5 quarts)

After cleaning and installing the pan with new gasket, filled it with 4 liters of WS (I was afraid of over filling it), and started the pump out and refill procedure every 2 liters disconnecting the hose at the top of the oil radiator. The oil was dark brown. After 2 more cans of 4L each, the oil exiting the hose was almost like the new one. Then a final step of adding until overflow at 40 deg C.

Haven't noticed any difference in shifting quality yet.

From left to right:

-Old oil
-Last drain from radiator hose (prior to the last partial refill with 2 liters of fresh WS)
-New WS fluid.

 

[2001LC]

I'd call that a drain and fill, W/pan cleaning.

But I'd warn anyone doing this: Do not run engine with pan off or empty. Just to risky!

 

[Caaarlo]

But I'd warn anyone doing this: Do not run engine with pan off or empty. Just to risky!

I am reluctant to accept this idea.

The transmission must have been designed to allow dry operation, even under heavy load, for a reasonable amount of time, because when going down a very steep hill, all of the oil in the pan migrates forward, the strainer inlet is then depleted from any oil and exposed to air, allowing the pump to run dry and stopping the normal oil flow. So, this is a possible condition of use that must have been tested at the factory, especially on such a capable off-road vehicle.

Furthermore, while in P or N, both the transmission and pump are not doing any kind of effort, just spinning freely, unloaded while still coated in oil. This is not dynamic lubricated or pressure-lubricated mechanism like the crankshaft bearings, its basically splash lubricated, so I really didn't see any danger, and the gearbox is working fine like always did.

 

[2001LC]

The transmission must have been designed to allow dry operation for a reasonable amount of time, because when going down on a very steep hill, all the oil in the pan migrates forward, the strainer inlet is then exposed to air, allowing the pump to run dry and stopping the normal oil flow. So, this is a possible condition of use that must have been tested, especially on such a capable off-road vehicle.

Furthermore, while in P or N, both the transmission and pump are not doing any kind of effort, just spinning freely while still coated in oil. This is not dynamic lubricated or pressure-lubricated mechanism like the crankshaft bearings, its basically splash lubricated, so I really didn't see any danger, and the gearbox is working fine like always did.

Sorry if I rub you wrong.

But, it's reckless of you to suggest in MUD. Anyone every run their transmission dry. If you were so sure, why did you stop and ask question of mud.

What you did was risky and needles. Even pulling pan is more or less a waste of time (the magnets do their job for life). You'd been better off and safer, to have just done a 12 qt flush and be done with it. Would have cost a little more, but taken less time. End result even better.

You statement: "Furthermore, while in P or N, both the transmission and pump are not doing any kind of effort" Then how come it pumps ATF out so fast, when doing a flush! True transmission not under load. But if you'd continued to run it dry. You'd like be replacing your transmission.

What does happen with any component just drained of oil/lucubrate. Some always remains coating parts, for awhile. It's how we can start and engine that sat for extended period of time.

BTW: All fluid levels are design with vehicle angle limitation in mind. Think about your statement: "designed to allow dry operation for a reasonable amount of time" What do you consider a reasonable amount of time. 2 minutes, 2 hours, 2 days.. We some very long an step mountains passes in Colorado. We also many instance where speed will be very slow. I've pull up and down a single hill for hours do to ski traffic, mud wash out ahead, flooding, accident, etc. just to name a few instances. Many place in the world have even long passes, on and off road.

 

[Caaarlo]

If you were so sure, why did you stop and ask question of mud.

What you did was risky and needles. Even pulling pan is more or less a waste of time (the magnets do their job for life). You'd been better off and safer, to have just done a 12 qt flush and be done with it. Would have cost a little more, but taken less time. End result even better.

You statement: "Furthermore, while in P or N, both the transmission and pump are not doing any kind of effort" Then how come it pumps ATF out so fast, when doing a flush! True transmission not under load. But if you'd continued to run it dry. You'd like be replacing your transmission.

What does happen with any component just drained of oil/lucubrate. Some always remains coating parts, for awhile. It's how we can start and engine that sat for extended period of time.

Of course I wasn't sure !!!! But I was looking for a more convincing explanation, not just "it's too risky". So I decided to go on after realising that going down a steep hill would make the pump run dry anyways. until the vehicle gets to a more horizontal terrain and the oil level allows for the strainer inlet to suck oil, not air. And this would be under heavy load !!!! for both the gearbox and the torque converter.

Regarding the effortless spinning of the pump: It takes less effort for the pump to move just air than having to move oil and pump it into the circuit. Just a matter of viscosity.

So, for the whole transmission, running dry for some seconds while in P or N would be much healthier than going downhill also dry as all the components will spin practically unloaded.

In other words, If going downhill is a perfectly normal condition especially for this kind of vehicle, and if this condition depletes the pump from oil, forcing it to run dry, then running dry for some seconds without load would be even less risky.

 

[2001LC]

Go for it man, run your transmission dry all you want.