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Where Is Transmission The Fluid Drain Plug?


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I just change the oil filter and oil without a problem until I went to add transmission fluid. When I checked the transmission while the truck was running it registered way over full in the HOT area.

 

1985 Chevy GMC 4x4 Sierra classic ATF drain plug?

 

Thanks

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Probably doesn't have one if the pan is stock

 

Yes,

 

It could be a stock pan which means I have to undo all those bolts and then change the seal and the filter.

 

I'm not on exactly flat ground. And I do not have a hydraulic jack so I have to scoot underneath the truck.

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Assuming you have a stock pan, there is no drain plug.

 

In case you arent aware of the procedure to drain the pan without making a mess, Ill go through it quickly. You may already know this but Ill post it up anyway.

 

You will need to crawl up under the truck, look up and find the transmission pan. Make sure you place a catch pan underneath and work from the side or or from under the engine if your truck is tall enough. Loosen each of the bolts starting from the rear of the vehicle, followed by each side, then finish by loosening the front bolts. As you loosen all the bolts the back of the pan will drop allowing the fluid to drain out with some control. Once its mostly empty, you can drop the pan without making a giant mess.

 

YOu can either install a drain plug into the factory pan, or install a new pan with a drain already in it. I added a deep Aluminum pan with a drain plug to my S10 when I changed the fluid. Made a world of difference. Ill probably do it with my current truck when I get ready to change the fluid.

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Do a search for "torque converter drain". Someone posted a really good procedure a few days ago.

 

Pulling the pan will only remove less than 1/2 of the fluid. If you dump the torque converter, you can get it all and make the pan a lot easier to pull off without making a mess.

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If you only need to drain a little, just unhook one of the cooler lines up front. I've heard of people draining the pan & TC by running the engine (at idle) with a line disconnected until it runs dry, but I've also heard that's HARD on the impeller blades in the TC when it gets low & the fluid starts to splash.

 

You can also buy a siphon pump that runs down the dipstick tube to remove fluid.

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I have also heard of people unhooking both lines from the trans cooler and putting the return line in a bucket of clean fluid, and putting th other line in an empty bucket. They ran the engine at idle until the new fluid runs out into the catch bucket. I personally dont like this method. I know dropping the pan only gets about half of the fluid, but Ive always been taught that this method is sufficient as long as you dont overheat the trans and cook the fluid.

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It doesn't work that way. The trans fluid is picked up from the full transmission pan, through the filter. If you put the other trans cooler line in a bucket full of clean fluid, it won't suck the fluid out and you may damage your trans.

 

When I do mine, I pull the pan, clean it, install a new filter then add the proper amount of new fluid to the trans. THEN, I remove the line that goes from the trans to the radiator (top line on my truck). I put a 3/8" clear plastic tube on that line and put the other end in a 2L (clear) soda bottle with a 1qt line drawn on it. Then I start the engine and let it idle until 1 qt has been dumped. (about 10 seconds) I shut off the engine and add a qt of ATF, then do the process again until the fluid changes color.

 

This takes the risk out of damaging the transmission and changes about 90% of the fluid.

 

Just changing the fluid in the pan gets less than 50% of the old fluid out. I wouldn't waste my time. IMHO that is not adequate unless you change the fluid ~ every 15-25K miles (depending on towing).

I have also heard of people unhooking both lines from the trans cooler and putting the return line in a bucket of clean fluid, and putting th other line in an empty bucket. They ran the engine at idle until the new fluid runs out into the catch bucket. I personally dont like this method. I know dropping the pan only gets about half of the fluid, but Ive always been taught that this method is sufficient as long as you dont overheat the trans and cook the fluid.
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Go to auto parts store and buy one of these fluid extraction pumps

 

ExtractionPump_300.jpg

 

Then go to hardware store and buy several feet of clear plastic tubing that will fit down the filler tube, slowly suck out the atf. No easier way and not mess..

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