# Help me change my transmission fluid?



## 4t7 (Sep 29, 2015)

Hi, I'm trying to change the fluids on my transmission and I need some help/advice. First of all it's on a 95' Chevy G20. I recently just got this van and didn't check the fluids as good as I thought I did/should have. Anyways upon checking the transmission fluid I realized it is way overfilled and the fluid looks really burnt and foamy. 

So how do I get all of this burnt trans fluid out to replace with fresh fluid? If I pull the transmission pan and let it drain that only drains about 50% of the old fluid right? How should I go about this?


----------



## 4t7 (Sep 29, 2015)

btw I plan on changing the trans filter as well while I drain the trans. I've got the new filter, gasket, gasket maker, and new fluid.


----------



## 4t7 (Sep 29, 2015)

My concern is that since only about half the fluid drains out when dropping the pan that half of this burnt fluid is still gonna be in the transmission...help!

How should I go about this?


----------



## ukrkoz (Dec 31, 2010)

Ahm, for starters, buy yourslef a personal protection suite. Kidding you not. If dropping that pan is anything like what it took to do on my Silverado, you'll be drenched in ATF, everything around will be, and it takes about 3 hrs.
Are you sure you do not have drain plug actually?
Some will say to locate your ATF radiator return line, disconnect it, turn engine on and it will gush out. Then you catch it all, size it up, and replace.
Some will say to suck it out through the filler tube, fortunately, GM made it rather good diameter.
But if none of those methods appeals to you and you want to drop the pan, this is what you do:
1. Look up on Youtube what others did
2. Drop the pan and FIRST thing you do is to cut in drain plug so that you do not have to deal with this bull anymore.
3. Should you have drain plug, you buy the best possible grip socket for the size, as on my Silverado, plug self welded to the pan and I had to drill it out - after pan removal
4. When you remove pan or reinstall it, be very careful with the trannie rear end. There are 2 connectors there for some solenoids that are super easy to disconnect and then you know what happens. 
5. Should you find that gear shifter cable bracket overlaps the pan lip and there is NO WAY to remove the bracket, you BEND it away from the lip, then bend it back. Yep. 
6. And now the final part. Actually, you drain about the 3rd of fluid. So you find out total capacity and drain and refill capacity. You drain, refill with refill capacity - usually 3 or 4 qrts - drive for about 15 miles, drain refill again, drive for 15 miles, drain refill. You just replaced, SAFELY, entire fluid at assumption it's 12 qrt total capacity.
Remeber what I said about cutting drain plug in? Make slife easier, aye?


----------



## Windows on Wash (Aug 30, 2011)

Google the "hoot" transmission fluid change.


----------



## 4t7 (Sep 29, 2015)

ukrkoz said:


> Ahm, for starters, buy yourslef a personal protection suite. Kidding you not. If dropping that pan is anything like what it took to do on my Silverado, you'll be drenched in ATF, everything around will be, and it takes about 3 hrs.
> Are you sure you do not have drain plug actually?
> Some will say to locate your ATF radiator return line, disconnect it, turn engine on and it will gush out. Then you catch it all, size it up, and replace.
> Some will say to suck it out through the filler tube, fortunately, GM made it rather good diameter.
> ...


Alright, thanks for the detailed reply. I'm pretty sure there is no drain plug. I lifted the van the other day and looked and couldn't find one.

step 3-4 you're saying I should make a drain plug on the pan for convenience next time I'm doing a drain?

and for step 6...

so I drain it
refill to fill capacity with new fluid
and then drive it for 15 miles, repeat. 
In between draining, refilling, and driving should I leave the old trans filter in or put in my new one? Also do I just put the pan on loosely and without sealing the gasket?

really appreciate the help btw.


----------



## 4t7 (Sep 29, 2015)

Windows on Wash said:


> Google the "hoot" transmission fluid change.


about to go google it now. Thanks.


----------



## ukrkoz (Dec 31, 2010)

If you are intending to drain/fill/drive/drain/fill - it is not feasible to drop the pan every time. You need to install drain plug in. Will be blessing to have one for the future anyway.
Because then you are NOT dropping pan anymore, you replace filter right away.
BTW, pour can of Transtune into that transmission for about 100 miles of driving before ATF change. Good medicine. 

Here's hoot for you

http://www.idahoturbodiesels.com/vb/showthread.php?t=3692


----------



## gregzoll (Dec 25, 2006)

If the fluid is burnt. That means that the Transmission has been abused. Replacing the fluid is not going to fix anything, other than make the local auto store some money.


----------



## 4t7 (Sep 29, 2015)

ukrkoz said:


> If you are intending to drain/fill/drive/drain/fill - it is not feasible to drop the pan every time. You need to install drain plug in. Will be blessing to have one for the future anyway.
> Because then you are NOT dropping pan anymore, you replace filter right away.
> BTW, pour can of Transtune into that transmission for about 100 miles of driving before ATF change. Good medicine.
> 
> ...


Thanks for the replies. I'm probably gonna do what you suggested. Wondering the best/cheapest way to install the drain plug on the pan?


----------



## 4t7 (Sep 29, 2015)

gregzoll said:


> If the fluid is burnt. That means that the Transmission has been abused. Replacing the fluid is not going to fix anything, other than make the local auto store some money.


Don't know how badly it's been abused. I do know the trans was way overfilled though. I hope it will help at least.


----------



## Brainbucket (Mar 30, 2015)

A good way, at home, to flush the tranny is to take a line off the radiator, fix a hose that goes into a drain pan, start engine and quickly shut it off to find out what line is pumping fluid into pan and adjust accordingly. Put a funnel in dip stick tube. Start engine and start filling trans as it is getting pumped out into pan. It will be dark at first but keep going. When it starts to get red, stop putting fluid in the trans and wait until the fluid starts to stop coming out of line. Not completely but when it starts to 'burb'. Stop engine. Change trans filter as most but not all fluid is out of pan. It will still be messy. Reinstall pan. Pour a couple of quarts of fluid in the tube and start engine and continue flushing trans until fluid is the same color as what you are putting in. Stop engine. Reattach line to radiator and start engine and check fluid level. NOW on the burnt fluid subject. Flushing trans MAY kill the tranny. Anytime trans fluid is burnt means it was abused, overheated, and/or not maintained with fluid services. I have saved trans and also killed them by flushing. If you have no troubles with your tranny before you flushed it, more than likely it will be ok. But if you have an issue with it and you flush it, well I wish you the best cause it's a crap shoot. Do not use any additives until you flush it with trans fluid only. You don't want to 'wash' it. You are already doing that by getting the old fluid out. Good luck.
PS> flush the trans cooler in the radiator also.


----------



## 1985gt (Jan 8, 2011)

Using the Hoot method you do not need to drop the pan every time. Just once at that end to replace the filter. IIRC just dropping the pan and filter you won't get out 50%. 

I like the removing the line and dumping in to a bucket. 

Brainbucket is spot on. flushing the tranny may in fact kill it. A lot of times it may just be better to drop the pan, change the filter and replace the fluid that was lost. Installing a drain plug is also a great idea, then just change the fluid a lot more frequently. 

I would personally lean toward not flushing the tranny and just changing the fluid ever 10k miles or so by dropping or draining the pan.


----------



## 4t7 (Sep 29, 2015)

Just got my drain plug kit in. It's raining here now and I'm eager to get this job done. 

Is it safe to work on my transmission in wet/humid/rainy environment?


----------



## WyrTwister (Jul 22, 2013)

Could you please post information on the drain plug kit .

Different question , if the drain pan does not have a magnent inside , what is the opinion or putting one in ?

Thanks ,
Wyr
God bless


----------



## 4t7 (Sep 29, 2015)

This is the kit I used:

http://www.amazon.com/gp/aw/d/B000C...i=AC_SX110_SY165_QL70&keywords=drain+plug+kit

Just put a little gasket sealer on it when installing and it's fine, or weld it on if that option is available to you.

I'd say if there is a spot for a magnet in the pan it probably won't hurt it if you put one in.


----------



## Dragfluid (Dec 30, 2013)

It's been a while since I've been around that vintage, but if you haven't already started on this, you will probably need to remove the transmission mount nuts and jack up the rear of the unit as far as it will go, then stick a piece of 2x4 or similar in between to keep it up. You need clearance for the pan. The shift solenoids are in the rear of the valve body, and you can't be forcing the pan past those, or you'll break them.

And I would use caution on adding any type of "drain plug" to the pan. Over the past 42 years of repairing transmissions, every single add on drain plug that I've seen people add LEAKED.

There should be a magnet already in there, but if someone had removed it, you can certainly add one. Just be sure to put it where it won't interfere with reinstalling the pan. And for a pan gasket, please don't use one of those rubber things that are folded up in the box with the filter. They leak. And you don't put any type of sealer on the gasket, either. Just a clean, dry surface. The best type of gasket is the brown or black paper type, but cork is fine too. Just be sure if using cork that it's totally dry, otherwise if it get's fluid on it, it will act like a wick.

Don't put any chemicals in the unit, please. None of that snake oil belongs in a transmission!! The only thing I condone is Lubegard, (yes, it's spelled correctly) which is nothing more than a enhancement to the lubrication qualities of the fluid. It's not a "conditioner", something that has no place in an automatic transmission.

If you want to replace all of the fluid, after you drop the pan and change the filter, remove the cooler line from the top of the radiator. Connect a line to the fitting on the radiator that you can run to the pail, etc. Start it up and let it run a few seconds until a couple of qts come out. Do this a few times 'till the fluid looks fresh. 12 to 14 qts should do it. If you have a helper keep an eye on the ignition switch, you may be able to keep adding fluid while it's running. Exchanging all of the fluid, will not hurt your transmission. But again, I stress, don't put any of that canned conditioner crap in it! Check the fluid level when the engine is running. It's full when it's on the cold mark when you get done with this. The fluid expands when hot, so it will then be on the full mark. If you happen to get it a little over full, it's not the end of the world.

Good luck!


----------



## 1985gt (Jan 8, 2011)

I just wanted to point out that there has been more then a few cases where flushing the transmission has done more harm then good. 

And... over filling the transmission can cause all kinds of havoc, in some having it a little to close to the full mark will and it will start acting up, being over full will accelerate the deterioration of the fluid.


----------



## Windows on Wash (Aug 30, 2011)

1985gt said:


> I just wanted to point out that there has been more then a few cases where flushing the transmission has done more harm then good.
> 
> And... over filling the transmission can cause all kinds of havoc, in some having it a little to close to the full mark will and it will start acting up, being over full will accelerate the deterioration of the fluid.


Agreed.

I will say that when I have seen folks have failures after a flush though, it was because they don't completely flush the system and a complete exchange of the fluids. When guys put in a cleaner and it loosens up debris, you have to completely exchange that fluid + about 4 quarts to ensure you have recaptured all the debris that has been introduced into the system via the cleaning.


----------

