Auto trans fluid change
Thread Starter
Instructor
Joined: Nov 2008
Posts: 114
Likes: 0
Auto trans fluid change
I have been around the computer world searching for info on how to change the automatic transmission fluid on a c-6. I took my car to the auto hobby shop and put it on a lift and couldn't find the fill plug. Please help me.
Melting Slicks
Joined: Jul 2007
Posts: 2,939
Likes: 7
From: Simpsonville SC
St. Jude Donor '09-'10
I've talked withi a lot of transmision shops about ever changing the fluid. The one I trust the most, who owna a transmission shop, says he would never change his fluid. Period.
He said two guys that bought the same car. One would change his tranny fluid every 20,000 miles, and the other would never change his. In the end it is a 50/50 chance on who's would die first.
Basically, when you change the fluid, be very careful not to get one spec of dust in the fluid. DO NOT POWER FLUSH the transmission. That will break up sediment that has been stuck to the sides, and get it caucht in a clutch pack; which woul casue a failure shortly after.
Ask me how I know all this...
He said two guys that bought the same car. One would change his tranny fluid every 20,000 miles, and the other would never change his. In the end it is a 50/50 chance on who's would die first.
Basically, when you change the fluid, be very careful not to get one spec of dust in the fluid. DO NOT POWER FLUSH the transmission. That will break up sediment that has been stuck to the sides, and get it caucht in a clutch pack; which woul casue a failure shortly after.
Ask me how I know all this...
Racer
Joined: Aug 2008
Posts: 494
Likes: 1
From: Fairbanks, Alaska
I've talked withi a lot of transmision shops about ever changing the fluid. The one I trust the most, who owna a transmission shop, says he would never change his fluid. Period.
He said two guys that bought the same car. One would change his tranny fluid every 20,000 miles, and the other would never change his. In the end it is a 50/50 chance on who's would die first.
Basically, when you change the fluid, be very careful not to get one spec of dust in the fluid. DO NOT POWER FLUSH the transmission. That will break up sediment that has been stuck to the sides, and get it caucht in a clutch pack; which woul casue a failure shortly after.
Ask me how I know all this...
He said two guys that bought the same car. One would change his tranny fluid every 20,000 miles, and the other would never change his. In the end it is a 50/50 chance on who's would die first.
Basically, when you change the fluid, be very careful not to get one spec of dust in the fluid. DO NOT POWER FLUSH the transmission. That will break up sediment that has been stuck to the sides, and get it caucht in a clutch pack; which woul casue a failure shortly after.
Ask me how I know all this...
They make replacement fluid for a REASON
Melting Slicks
Joined: Jul 2007
Posts: 2,939
Likes: 7
From: Simpsonville SC
St. Jude Donor '09-'10
The owner of a local 'Mr. Transmission' told me he has never changed the fluid in any of his cars. He is the most fair transmission shop I have ever been to. He does not want to rebuild every transmission that comes in. He will actually repair them, and charge a lot less than most.
Pro
Joined: Apr 2007
Posts: 650
Likes: 4
From: Pittsburg Ca.
The owner of a local 'Mr. Transmission' told me he has never changed the fluid in any of his cars. He is the most fair transmission shop I have ever been to. He does not want to rebuild every transmission that comes in. He will actually repair them, and charge a lot less than most.
Last edited by Slick Rick; Apr 13, 2009 at 12:27 PM.
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Pro
Joined: Aug 2004
Posts: 678
Likes: 0
From: Boise ID
Power flushing is a well known taboo for almost any car. Especially as they get older and build up sediment. My friend owns three transmission shops. Just do a Google search and see all the destroyed transmissions that have resulted from it.
Le Mans Master
Joined: Oct 2004
Posts: 9,369
Likes: 4
From: Zephyrhills, Florida
St. Jude Donor '06-'07-'08-'09-'10-'11-'12-'13
This is why I've never done the fluid change....I've heard this scenario more times than not. GM doesn't have any scheduled change at all for a C5 automatic.
Pro
Joined: Aug 2004
Posts: 678
Likes: 0
From: Boise ID
There's nothing wrong with changing fluid, and its recommended. Drop the pan and do partial changes. The power flush method can and does dislodge sediment buildup into the transmission, especially on older cars.
Burning Brakes
Joined: Aug 2005
Posts: 772
Likes: 6
From: Huntsville AL
My 2000 manual calls for a fluid change at 100,000 miles.
Not sure what is really meant by a power flush. The local shop I use does a complete swap of the fluid with a machine they hook up to the coolant lines. You crank the car and allow the transmission to pump fluid out thru the feed to cooler line and back to the tranny thru the return line. This swaps all the fluid including the torque converter. Have done this type fluid swap on many cars and never had a problem. When I purchased my 2000 it had 28k miles but since I had no idea how the car had been treated and it had been thru several owners, I decided to do this type fluid change using Mobile 1 fluid. I purchased the fluid and they used it in their machine. I could definetly tell a difference in the color of the fluid coming out and the new going in. I could also tell a difference in the smoothness of the shifts after the change.
Just my 2 cents worth.
Not sure what is really meant by a power flush. The local shop I use does a complete swap of the fluid with a machine they hook up to the coolant lines. You crank the car and allow the transmission to pump fluid out thru the feed to cooler line and back to the tranny thru the return line. This swaps all the fluid including the torque converter. Have done this type fluid swap on many cars and never had a problem. When I purchased my 2000 it had 28k miles but since I had no idea how the car had been treated and it had been thru several owners, I decided to do this type fluid change using Mobile 1 fluid. I purchased the fluid and they used it in their machine. I could definetly tell a difference in the color of the fluid coming out and the new going in. I could also tell a difference in the smoothness of the shifts after the change.
Just my 2 cents worth.
Good discussion.........I want to hear more! 
Advanced
Joined: Jun 2008
Posts: 91
Likes: 0
From: taos nm
Had mine flushed just before our 1700 mile trip and the trans ran cooler and better. Stopped at texas speed and had the computer tune, and now the car really runs good!! Hope to post pictures of our trip later today.
Melting Slicks
Joined: Sep 2006
Posts: 2,736
Likes: 7
From: Redding CA
Is there any way to just top off the fluid in our C5's? I just have to disconnect my cooling lines and I'll probably lose a little bit of fluid while they're off and I'll have to put some fluid back in...
Thanks,
Donnie
Thanks,
Donnie
Racer
Joined: Nov 2008
Posts: 378
Likes: 0
On my '99, the drain plug and fill plug are one in the same. You have to have the car running to do this and I wouldn't do it unless it was on a lift.
Melting Slicks
Joined: Apr 2007
Posts: 2,167
Likes: 55
From: Kempner TX
St. Jude Donor '08-'09
Once a transmission starts falling apart on the inside its not wise to change the fluid. Tranny fluid is a detergent and a bad transmission will fail very shortly after its serviced because you just cleaned out basically what was holding it together.
If you change it regularly the tranny will last forever. If you wait till you are at 100,000 miles and then change it the chances are you will be purchasing a new tranny in the near future. My F250 has 170,000 miles on it and I change the fluid every 30,000 miles. It hasnt missed a lick yet.
P.S. Mr. Transmission does sound like he doesnt know what he is doing.
If you change it regularly the tranny will last forever. If you wait till you are at 100,000 miles and then change it the chances are you will be purchasing a new tranny in the near future. My F250 has 170,000 miles on it and I change the fluid every 30,000 miles. It hasnt missed a lick yet.
P.S. Mr. Transmission does sound like he doesnt know what he is doing.
Drifting
Joined: Sep 2004
Posts: 1,464
Likes: 7
I've talked withi a lot of transmision shops about ever changing the fluid. The one I trust the most, who owna a transmission shop, says he would never change his fluid. Period.
He said two guys that bought the same car. One would change his tranny fluid every 20,000 miles, and the other would never change his. In the end it is a 50/50 chance on who's would die first.
Basically, when you change the fluid, be very careful not to get one spec of dust in the fluid. DO NOT POWER FLUSH the transmission. That will break up sediment that has been stuck to the sides, and get it caucht in a clutch pack; which woul casue a failure shortly after.
Ask me how I know all this...
He said two guys that bought the same car. One would change his tranny fluid every 20,000 miles, and the other would never change his. In the end it is a 50/50 chance on who's would die first.
Basically, when you change the fluid, be very careful not to get one spec of dust in the fluid. DO NOT POWER FLUSH the transmission. That will break up sediment that has been stuck to the sides, and get it caucht in a clutch pack; which woul casue a failure shortly after.
Ask me how I know all this...
And ask me how I know this about the Power flush. 
Pro
Joined: Oct 2004
Posts: 538
Likes: 0
From: Edmond Ok
Thanks all.