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Dorman makes a replacement trans pan with a drain plug in it. If you want to change the fluid peacemeal, I would start by replacing the pan with the dorman one, along with a new filter, and then just do a drain and fill every oil change until you are satisfied with the color that is coming out. It will take more fluid to do it that way than just changing it all at once, but simply opening a drain plug and refilling the trans is quick and easy, and overall you will spend way less time doing that than trying to siphon the fluid up and out of the dipstick tube.
 

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1995 Thunderbird LX 4.6 red
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Dorman makes a replacement trans pan with a drain plug in it. If you want to change the fluid peacemeal, I would start by replacing the pan with the dorman one, along with a new filter, and then just do a drain and fill every oil change until you are satisfied with the color that is coming out. It will take more fluid to do it that way than just changing it all at once, but simply opening a drain plug and refilling the trans is quick and easy, and overall you will spend way less time doing that than trying to siphon the fluid up and out of the dipstick tube.
I've used that Dorman pan and it's a pretty nice piece for being about $30. I agree with MadMikeyL find a way to just drop the pan and do that job. It'll make your life easier in the long run.
 

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I didn't care for the Dorman pan. I looked at it at Advance, and walked out without it. The sealing lip didn't give me a warm, fuzzy feeling. Might be fine, but I didn't want to chance it.

I would try to change all the fluid at once. Doing a little at a time, you will end up throwing away a lot of your new fluid, would take 20+ quarts. If you can get under the car and drop the pan, you can also drain the torque converter. Job done.

Don't forget the filter, and either re-use the stock gasket or buy another Ford gasket. Those thin rubber ones that come with the filter aren't any good.

Al
 
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I wonder if they started cheaping out on the pans. It has been a few years since I bought one, but I remember being surprised how thick and heavy duty it was for a dorman part. It definitely felt way more solid than the original Ford pan.
 

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It was pretty thick, but the sealing lip looked wavy in the corners, not flat. It's been several years.

Al
 

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1995 Thunderbird LX 4.6 red
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I've used a couple of the dorman pans in the last 2 years. They've all been good. With the factory gasket, no leaks.
 

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I add a drain plug into the ones I rebuild, it just makes sense.
 

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When I was a teenager I had a 92 grand marquis. I was able to get it up on jackstands and do a full trans fluid change in my parents driveway. I don't recall if I had to drop the pan on it or if it had a drain plug. I remember pushing the flex plate around to find the torque converter drain.
Guess what I am getting at is if my dumbass teenage self could drain and fill all the fluid.... it isn't that hard a job. :ROFLMAO:

I went ahead and siphoned out a quart just to see what it looks like. Pretty dark, but not black, and no burnt smell.
That looks bad. You will notice a big improvement when you get fresh fluid in.
 

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Discussion Starter · #32 ·
@supergordo, @Kenz, I'm increasingly betting that this may be the original Mercon fluid. The original owner (23 years and about 29,000 miles) was very good to the car, but technically a transmission fluid change isn't until 30,000 miles (I realize you should consider mileage and time, but they may not have); the second owner (1,5 years and about 10,000 miles) only did oil changes.

Meanwhile, this siphoning exercise did help me make up my mind about how to proceed:

I will do the pan drop, filter change and torque converter drain. But before the pan drop, I will siphon out the fluid to minimize the mess.
I realize a lot of people recommend disconnecting a cooler line and then using the engine to pump the fluid from the pan out, but I just don't like that idea honestly. I'm not saying there's anything wrong about it; but personally I find the siphoning so much easier and cleaner, with essentially the same result.

I may not get all the fluid out. If I don't disconnect the cooler lines, I imagine that most of the fluid in the lines and in the radiator will remain. That being a fairly small amount (maybe 1-2 quarts?), I can live with it.
 

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@supergordo, @Kenz, I'm increasingly betting that this may be the original Mercon fluid. The original owner (23 years and about 29,000 miles) was very good to the car, but technically a transmission fluid change isn't until 30,000 miles (I realize you should consider mileage and time, but they may not have); the second owner (1,5 years and about 10,000 miles) only did oil changes.

Meanwhile, this siphoning exercise did help me make up my mind about how to proceed:

I will do the pan drop, filter change and torque converter drain. But before the pan drop, I will siphon out the fluid to minimize the mess.
I realize a lot of people recommend disconnecting a cooler line and then using the engine to pump the fluid from the pan out, but I just don't like that idea honestly. I'm not saying there's anything wrong about it; but personally I find the siphoning so much easier and cleaner, with essentially the same result.

I may not get all the fluid out. If I don't disconnect the cooler lines, I imagine that most of the fluid in the lines and in the radiator will remain. That being a fairly small amount (maybe 1-2 quarts?), I can live with it.
You don't have to disconnect the cooler lines. If you want to minimize the mess, drain the converter first. That will get several quarts out before you drop the pan. And as far as the pan goes I suggest removing all the bolts except one in each corner of the pan. then you can slowly lower the rear two bolts then a little on the front two. Then you can control the drain of the fluid. It's not a perfect system, but you don't have to make a huge mess at all.
 

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Discussion Starter · #34 ·
You don't have to disconnect the cooler lines.
Well, I just re-read that old TSB...


...and now I'm wondering about that. The TSB states that any residual fluid in the lines can cause shudder, and to drain all fluid completely. Maybe they just wanted to make sure dealerships weren't cutting corners back then.

Questions:

Once the pan is lowered, if I simply disconnect the upper radiator line, will the fluid in the lines and radiator drain down to the pan (gravity plus air entering the line and radiator from the top)?

And a more general question: how exactly does fresh fluid get into the torque converter (and air out of it) after draining it? From what I'm seeing, the torque converter is an enclosed fixture with just one opening in the aft middle. But that opening is where the transmission shaft goes in. Sorry if this is a dumb question; just trying to understand the overall workings of it.
 

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Discussion Starter · #35 ·
When I read anywhere "deep pan", is that just in reference to the small, slightly deeper area in the middle (marked red in the picture) as opposed to an entirely flat pan? Or does "deep" refer to a pan which is deeper as a whole?
 

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1995 Thunderbird LX 4.6 red
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When I read anywhere "deep pan", is that just in reference to the small, slightly deeper area in the middle (marked red in the picture) as opposed to an entirely flat pan? Or does "deep" refer to a pan which is deeper as a whole?
View attachment 50137
That's the deep pan.
 

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1995 Thunderbird LX 4.6 red
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Well, I just re-read that old TSB...


...and now I'm wondering about that. The TSB states that any residual fluid in the lines can cause shudder, and to drain all fluid completely. Maybe they just wanted to make sure dealerships weren't cutting corners back then.

Questions:

Once the pan is lowered, if I simply disconnect the upper radiator line, will the fluid in the lines and radiator drain down to the pan (gravity plus air entering the line and radiator from the top)?

And a more general question: how exactly does fresh fluid get into the torque converter (and air out of it) after draining it? From what I'm seeing, the torque converter is an enclosed fixture with just one opening in the aft middle. But that opening is where the transmission shaft goes in. Sorry if this is a dumb question; just trying to understand the overall workings of it.
Don't over think all of this. You are not going to get 100% of the fluid out. The torque converter gets filled when you fill the trans. Air goes back out the filler tube and/or the vent on top of the case. You don't have to do anything special except take the time to make sure you get the fluid level correct on the dipstick. Once you've dropped the pan and drained the converter, it really will take about 12 quarts of fluid, maybe more. The only way you'd empty the cooler in the radiator would be to disconnect the cooler lines and blow them out with an air hose and/or Kooler Kleen. But unless your trans is failed, you don't need to worry about that. The small amount of old fluid left will be diluted with the new.
 

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It's a waste of time to disconnect the cooler lines to dry and drain every last drop. Like Supergordo said the amount that is left in the cooler lines is insignificant with the amount of fluid the transmission holds. IIRC it ended up taking 13+ quarts when I last did a drain and fill on a 4r70w

Don't try to use air to blow out the lines. I did that on my cooler to clean it out since it's not used with my manual. It made a vaporous explosion of transmission fluid under the car and coated everything. I did get all the fluid out of it though!
 

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12 is usually enough. When the valve body is removed, then you need that 13th quart.

What draining the system from the cooler line does, is keep you from making a mess when removing the pan, it is mostly dry. But you do have to rig up a fitting and hose for the radiator, and run the car for 30 seconds.

Al
 
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