Transmission Fluid Flush??

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MichaelSE

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Can the previously linked flush method be done without changing the filter? It looks so easy to do, minus removing the pan, that I'd like to do it sooner rather than later. I still plan to drop the pan and change the filter, but does it have to be done at the same time as the flush?
 

TheAutumnWind

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Can the previously linked flush method be done without changing the filter? It looks so easy to do, minus removing the pan, that I'd like to do it sooner rather than later. I still plan to drop the pan and change the filter, but does it have to be done at the same time as the flush?

No, the only issue is that when you do drop the pan you will have to pump the fluid out anyways. I suppose if you catch it in a clean container you could reuse it.
 

MichaelSE

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No, the only issue is that when you do drop the pan you will have to pump the fluid out anyways. I suppose if you catch it in a clean container you could reuse it.

Thanks. I'll probably just use new fluid when I eventually drop the pan, AC Delco Dex VI is cheap now, just $21 a gallon on Amazon. Plus another drain and fill is always good peace of mind.
 

NGAneer

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Keep in mind there's going to be garbage in the pan when you change the filter. I wouldn't resuse what came out of the pan, personally. Until you drop the pan and clean it out, you won't have all the "junk" out of the fluid. You'll just be putting that junk into your new fluid.
 

K2 Kaiju

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I had classic in grapevine do it for $153. I specifically asked about the dangers of flushing, and the rep said it uses the trucks pump to evacuate as it fills just like the home method. When looking at the time, mess, and recycle fluid pita, this was an easy choice. My manual says 47500 miles.

Sent from my SM-T350 using Tapatalk
 

Meccanoble

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The filter is the easiest part of changing so you might as well. I think its worth getting someone to do the work at the price only if you know they are going to do it completely and the right way. Once the pan is put back on and everything reinstalled, you wont know anything was missed unless you go back and check for yourself or watch them do the entire process.

Things that can be easily missed:
1) cleaning the pan after dropping
2) cleaning the magnet
3) flushing until fluid is clear/clean
4) installing the pan (if a screw broke, it probably wont leak but you probably wont be going under the car to find out
5) Filter actually replaced? Pan gasket replaced? You may ask for these things but its more preventative and what proof you got they were changed?

This applies to everything done on the car. Hell, I've heard of mechanics sabotaging cars so you come back for another issue.

Only time I feel confident going to a mechanic is one I built strong repore (sp?) with through multiple ventures and obvious issues that the fix can be seen/heard. (HUB bearing, tires, axles)

This job can be such a mess, if you ever have to drop the pan for any reason, you just want to do the entire job so you never have to worry about it for a long time. You could use the same fluid if it was still super clean but unless it has less than 10k miles, why not just start fresh especially on a part of the car that somewhat commonly fails on theshe cars.
 

MichaelSE

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Keep in mind there's going to be garbage in the pan when you change the filter. I wouldn't resuse what came out of the pan, personally. Until you drop the pan and clean it out, you won't have all the "junk" out of the fluid. You'll just be putting that junk into your new fluid.


You've convinced me. I have a new gasket and filter on order.
 
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2013 Tahoe 4WD

Just had my 40k mile oil change done at the dealership and the service rep recommended a transmission fluid flush to the tune of $300. I pointed out that the GM service manual requires this at 97,500 miles. He became agitated and told me to "do whatever I want".

I don't tow with the vehicle. It's a daily driver. Is a transmission flush at 40k miles legit?
 
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Tell that dealer to suck it. I hate when salesman say stupid shit like that. The trans fluid should be changed between 60,000-75,000, depending on how hard you run the truck. 97,000 is for grandma that don't go over 2500 rpm lol.



2013 Tahoe 4WD

Just had my 40k mile oil change done at the dealership and the service rep recommended a transmission fluid flush to the tune of $300. I pointed out that the GM service manual requires this at 97,500 miles. He became agitated and told me to "do whatever I want".

I don't tow with the vehicle. It's a daily driver. Is a transmission flush at 40k miles legit?
 

MichaelSE

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Well, I tackled this job today. Not going to lie, it was pretty frustrating, especially for a shadetree like me. I'll post my experience, hopefully it will help someone out. It took me about 4 and a half hours.

Breakdown of costs:
4 gallons ACDelco Dexron VI: $24x4 = $96
ATP gasket & filter set: $20
Cooling line adapter: $11
10' of 3/8" ID hosing: $5
Pick tool set from Harbor Freight: $3
Degreaser/shop towels for the pan: $7
Total: $142.

The dealer wanted $339 for this service.


The first snag I ran into was getting the c-clip off the "quick release" cooling line. If you think your pick tools are small enough, chances are, they aren't, you need a really freaking tiny pick tool to get that off there. I messed around with it for 15 minutes until I got the end of the pick around the clip. Having barely any room to mess around below the coolant line doesn't help either. There's probably a specialized tool for removing the clips but whatever, I don't do this often enough to buy it. Then when I was putting the adapter on, my fear came true, I dropped and lost the clip. Unless you put it on just right, it will pop out and go flying. I taped the hose in place so it wouldn't fall out while pumping fluid. Draining the fluid went well. Just as the tutorial says, it'll pump about 3.5-4 quarts out in about 30 seconds before it starts to bubble. My old fluid was dark brown. Once I got that out, I went underneath to get the pan out.

The pan bolts come off easy. They're 10mm. I was able to use the lever method that Meccanoble used (thanks for that one, man) to lower the exhaust, but it was nervewracking because you're forcing the exhaust to go where it doesn't want to go. Even with that it was a huge pain to get the pan off. It will get hung up on a component on the passenger side, then when you slide it forward, it will get caught on the cooler lines. There's a 15mm bolt holding the cooler lines in place that you can take off to get a tiny bit more movement, but since they're hard lines they don't move much. I had to twist the pan sideways just right to pull it out. It had about a half a quart in it. Worth noting that on a 6L80e you don't have to remove the shift linkage or even the heat shield!

The filter comes off easy, but the ring gasket above it is another story. It was jammed in the bore pretty good. I used wire-cutters to cut a notch in the side, and then another notch, and from there I was able to get a screwdriver in between the bore and the ring. Once you can bend it, it will come out no problem. The new one fit tight, but you can tap it in with a 7/8" socket on an extension and a hammer. I just kept tapping until it looked like it was touching the transmission. After that's in, the new filter should give you zero trouble going on.

Oh yeah, Simple Green worked wonders for cleaning the pan. The magnet was a pain to clean since all the tiny tiny shavings want to stick to it.

My old gasket looked good, but I decided to put the new one on anyway. When you do this be sure to clean the area underneath where the gasket was. Mine was a tiny bit misshapen so that the locator pins didn't want to stick directly up. This made it a huge pain in the ass to get it lined up. Get two of the bolts handy so you can put one on the front and one on the back as soon as you get the locators lined up. GM recommends tightening the bolts in a certain order. Is it important? Not sure, but I wasn't going to take the chance. I torqued them up in that order to 80 in-lb. and refilled the transmission. When I started the truck, the fluid was coming out really slowly, and in spurts, so I was freaking out thinking that I messed up the pump or something. But I shut it off, turned it back on, and it began flowing like normal again. I got about 3 more quarts out. Did that process twice more. Then the fourth time, I filled the transmission to the cold fill line. I had 16 quarts and used them all. Glad I left a full gallon for the final fill, because it took all of it.

It was about this point that I finally found that damn c-clip. It was on that flat plastic area right in front of the wheelwell retaining plastic. Maybe yours is there too if you drop it.

Here's where the fun starts, I took off the hose and reconnected the cooler line, started the truck, drove around the block, parked it and let it run. Before long I look underneath and see a nice pool of red. So, got back underneath, seems the leak was coming from the rear of the gasket, even though I am 100% certain that the locator is lined up and those bolts are torqued to spec. I decided it couldn't hurt to go above the spec just a tiny bit, so I grabbed my 3/8 ratchet and turned each bolt about a quarter turn. Not much at all. I just finished an hour ago and that seems to have stopped the dripping, but there's still moisture there even after I dried everything off. I don't know, maybe the new gasket needs to swell up? Hopefully it quits leaking but I'll be keeping an eye on it.

Anyway, my truck has 130k miles and unknown history on the transmission. It never shifted badly besides some hard shifts at WOT. Can't wait to take it out on the desert roads and see if that's improved. If anyone has any questions about the flush, feel free to ask. I'd be glad to help out. It's worth it for the peace of mind. If I can do it, you can too.
 
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