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Posted

I called one of my local Chevy dealers to get a price on a transmission service and he stated that they recommend a transmission flush. He stated that it flushes all the old fluid out and gives you about 18qt’s of new fluid. He said it was $195 but what gets me is that he says they dont drop the pan and change the filter. He said they do offer a drain and new filter for about $140 but it leaves most of the fluid in the torque converter. My truck has 75k miles and about 2100hrs. Whats the best solution here?

Posted

Well, I would drop the pan and change the filter and refill with fluid until it’s full. That’s an actual service procedure that GM uses. GM does not support flushing of any components.


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Posted

I just did my own last Friday. All I did was drop pan and change internal filter. Took about 6.5 quarts of fluid. From what I've read on here that is what most everyone does. If they don't change the filter when they flush I don't see the point really. It's like changing your engine oil and not changing the filter.

  • Like 1
Posted
2 hours ago, Justin101714 said:

Well, I would drop the pan and change the filter and refill with fluid until it’s full. That’s an actual service procedure that GM uses. GM does not support flushing of any components.


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Yeah and u’ll get a whopping 2 quarts of new fluid

Posted

Dropping the pan and changing the filter will exchange only about 6 quarts.  GM dealerships and the repair manuals all use the fluid exchange machine which back flushes the filter and they reverse the lines and exchange all the fluid for new.  The machine is called the TransFlow and my service manual has the procedures on how to use it.  Dropping the Y-Pipe or moving the crossmember is a pain for this oldster.  I took mine in to the dealer and had them do the fluid exchange.  Works perfect still.

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Posted

Transflow is used to get the transmission cooler flow code for warranty repairs. You cant back flush when the transmission pump is running, which you have to have the engine running to flush, it only flushes one way.


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Posted (edited)

Personally I would ask them to do both. Drop the pan, change the filter, and flush it. It’s really the only way to really change all the fluid and the filter.

Edited by truckguy82
Posted

I think im just going to do the flush. One thing he did say and i have never heard of this is that they flush all the old fluid out and then they flush a cleaning agent through. After the cleaning agent, they refill it with new fluid. Is this cleaning agent flush normal?

Posted
I think im just going to do the flush. One thing he did say and i have never heard of this is that they flush all the old fluid out and then they flush a cleaning agent through. After the cleaning agent, they refill it with new fluid. Is this cleaning agent flush normal?
Splitting hairs, but you're describing a flush while others are describing an fluid exchange, which are similar but different (the cleaning agent being the difference).

I would not do a powered flush with a cleaner, I would not do a powered exchange.

The only safe way to exchange fluid is using the transmission's own pump to pull fresh fluid in and to push the old fluid out.

My opinion...

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Posted

Just an update. I called all 3 Chevy dealerships in my area and all said the same exact thing on doing a flush and not needing a filter change.

Posted

I do my own filter and fluid change. Like has been said I got about 6.5 quarts with my change when I did it around 70k miles. At 80k I used a pump and pulled one gallon out the dipstick tube and poured 1 gallon back in. I just rolled past 91k. I am going to wait until 95k and pull another gallon out and refill. My plan is to continue to do 1 gallon swaps every 15k and filter swaps every 50k.

 

My first fluid change the oil looked almost brownish. I'm on my phone or I would attach a picture.

Posted

What I did was drop the pan and change my filter and 6 quarts fluid at 115,000 miles (I bought it used at 94,000). Then the next weekend I unhooked the trans fluid cooler line by the radiator and started the engine, let it pump until the flow slowed (4 quarts exactly) shut it off and then refilled 4 quarts, restarted it and let it pump until it slowed (4 quarts exactly again) then refilled 4 quarts. By then, the fluid was a medium-dark red, it was pretty much black and not transparent before I did the filter/fluid change the first time and I'm sure the way I did it I mixed a lot of old and new fluid... Probably wasted a few quarts of new fluid but oh well. I feel better because I have the magnet clean and a new filter, and mostly new fluid, and the transmission seems to be operating normally. BTW my friend is the store manager at a local NAPA store, so I got their house brand (made by Valvoline) Dexron VI synthetic fluid for $4.10 a quart, so the whole thing plus filter only cost me around $65. It is sort of.... involved... though, for all you DIYers out there be ready to cuss GM for that exhaust pipe they routed directly under the transmission pan. Otherwise, easy-peasy.

Posted
On 10/19/2017 at 9:38 AM, GMcD said:

I think im just going to do the flush. One thing he did say and i have never heard of this is that they flush all the old fluid out and then they flush a cleaning agent through. After the cleaning agent, they refill it with new fluid. Is this cleaning agent flush normal?

ATF......is a detergent.

 

The cleaning agent thing is a scam.

Posted

Do it yourself. If you remove the pan and change the filter you will only get about 1/3rd of the fluid. Perform a flush, then remove the pan and change the filter. Lots of service videos on YT on GM transmissions, you are just taking one line of the tranny cooler and pulling the new stuff through the system. I have been meaning to do my 6L80e as it having solenoid issues (locking itself into second gear at 35mph lol).

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