Changing ATF.

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I have a 2000 suburban. I have never changed the AT fluid. I have heard over the years that if you wait too long to change it you may as well not change it as when you do, the new fluid will cause problems with the seals. I have no idea whether there is any truth to it or not. Maybe some of you gurus can tell me whether or not there is any merit to this claim.

BTW, I am currently at 170K and having no issues with my transmission.
 
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New fluid will clean all the sludge and varnish out of the transmission. It is very important to change the transmission filter during this process. Lots of high mileage transmissions fail after a fluid change, cause the filter was not changed. The cleaning action clogs the filter and starves the transmission for proper lubrication.

I would change it. But change the filter after you change the fluid.
 
Are you saying to change the fluid, let it run for a few days, and then change the filter or just do it all at once.

I had planned to change the filter.
 
Originally Posted By: Viscosity
Are you saying to change the fluid, let it run for a few days, and then change the filter or just do it all at once.

I had planned to change the filter.


Yeah pretty much what im saying. You could change the filter twice if you'd like, once when you start, then again maybe a week or two later.

IDK how hard it is to change trans fluid on your truck, whatever is feasible for your wallet and time.

Have you done the diff fluid in the truck yet?
 
I would drop & clean the pan, change the filter and refill with Dex VI. Since you are only changing about half the fluid this way, I would do it again in 6 months.
 
Originally Posted By: PhillyJoe
I would drop & clean the pan, change the filter and refill with Dex VI. Since you are only changing about half the fluid this way, I would do it again in 6 months.


This plus installing a $20 Magnefine inline filter to catch all the loosened crud hopefully before it circulates too much.

One thing thing to remember is no flush or chemical can do a good job cleaning the filter. It needs to be replaced. Some like to say they can flush the ATF and by adding a chemical it will clean the filter too.
 
Originally Posted By: randomhero439
New fluid will clean all the sludge and varnish out of the transmission. It is very important to change the transmission filter during this process. Lots of high mileage transmissions fail after a fluid change, cause the filter was not changed. The cleaning action clogs the filter and starves the transmission for proper lubrication.

I would change it. But change the filter after you change the fluid.
Baloney!!! This is not true at all. Most modern cars don't have a filter, it's a metal mesh screen that's called a filter.
 
In the 4L60E I would recommend changing the filter since its a paper felt type. Since the pan has to be removed to change the fluid (some don't have drain plugs) might as well change the filter and clean out the pan.
 
Be thankful you have a dipstick! "Modern" transmissions lack this basic feature. *grumble*
 
Fresh fluid should help preserve your transmission for longer, and a pan drop and refill now, then again in 5-10k miles, then repeat every 30k after that should see you through.
 
Originally Posted By: randomhero439
Have you done the diff fluid in the truck yet?


Nope. I need to do that as well.
 
How does the color look on the dipstick if you blot it on a white towel? Just curious. I recommend Supertech dex 6 at Walmart it's less than $4.50 a quart and pretty good stuff.
 
Originally Posted By: NightRiderQ45
Most modern cars don't have a filter, it's a metal mesh screen that's called a filter.
You can't make a blanket statement like that. Ford RWD vehicles with the 4R70W have a regular "media" filter. So does my sister's '08 RAV4...

How come no one ever advises installing a drain plug on transmissions that don't have one? I install them on every car I own and it makes doing regular drain & fills a lot quicker and a LOT less messy.
 
@RF, I always advise to install a drain plug, especially if there is an aftermarket pan with one available.

@OP and everyone else, I guess:
I thought these trucks had a drain plug.

If so, then you don't need to drop the pain. Just drain thru the drain plug.
 
I checked it with a white rag and it's reddish in color.

Additionally, there appears to be a drain plug on mine. However, I'm planning on changing the filter so the pan is coming off. Any advice on putting the pan back on. Should I put it back on dry or use a sealant?
 
If the color is red then you are probably good to drain and fill it 2 times before you run any risk of plugging the filter i would think. On the 3rd drain and fill you can replace the filter and pretty much be done with it for awhile except 30k single or double drain and fills.

If you want to get all drain and fills done at once you only need to drive it a little while to mix it all up before you let it cool off, i suggest up to 10 miles if its possible. I have a nice little loop around my interstates i take to and back to where i drain it. I suspect its possible to mix it all up with less driving but i can't be sure.

As far as the gasket goes, i think its cork and i don't think they are reusable. You want the re-usable fel pro gasket which might be possible to find locally and found easily online.

First place to check is Autozone or Oreillys etc, they should be able to order it if not in stock. If you have a summit racing near by there you go. Or online.

http://www.summitracing.com/parts/fel-tos18663/overview/make/chevrolet

http://www.amazon.com/Fel-Pro-TOS18663-Oil-Pan-Set/dp/B000C2AO66

http://www.oreillyauto.com/site/c/detail/FEL0/TOS18663.oap?year=2007&make=GMC&model=Sierra%2B2500%2BHD&vi=1438273&ck=Search_03233_1438273_-1&pt=03233&ppt=C0073




EDIT: If you buy certain filters they come with a new cork gasket, you should be able to lube it lightly with ATF and use that, otherwise the fel pro probably a better bet as its a nitrile blend.
 
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I would always prefer to use a gasket unless there was a big stipulation not to by the car maker.

I used a rubber/nitrile gasket on my father's van transmission with success. The mess the Chrysler factory made using sealant just made me want to even more.

My past VW there was no oil pan gasket available so I had to use sealant but that wasn't too bad.
 
I agree about doing one or more drain and fills before dropping the pan. Just be really careful removing the plug. They're tight and the corners are easy to strip.

If you're concerned about new fluid causing problems, (which it should not if the trans is sound to begin with), do one pan drain and drive awhile, then repeat as many times as you want before changing the filter.

If you install a Magnefine inline filter, you could do a cooler line flush to get even more of the old fluid out instead of doing multiple pan drains.
 
Originally Posted By: Donald
Originally Posted By: PhillyJoe
I would drop & clean the pan, change the filter and refill with Dex VI. Since you are only changing about half the fluid this way, I would do it again in 6 months.


This plus installing a $20 Magnefine inline filter to catch all the loosened crud hopefully before it circulates too much.

One thing thing to remember is no flush or chemical can do a good job cleaning the filter. It needs to be replaced. Some like to say they can flush the ATF and by adding a chemical it will clean the filter too.


That's what I would do! Good plan right there.
 
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