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Trany flush on high mileage silverado

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Old 08-02-2009, 08:16 PM
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Default Trany flush on high mileage silverado

So I figure I would get some opinions on getting a tranny flush. I got the truck around 62k and currently has 70k right now. I don't know if the tranny was ever flushed but I wanted to to swap out from the Dex III to the Dex VI with new filter of course. What would you guys recommend? Current tranny fluid is pink and does not smell.
Old 08-02-2009, 10:18 PM
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I'm a firm believer in NEVER changing the tranny fluid until the thing blows apart. I've just never had good luck with it. It seems to be hit or miss.
For the record, my last truck had the original fluid in it when I sold it at 225,000 miles....

Because you said it wasn't burnt, you might be able to get away with it. Honestly, I still wouldn't though.
Old 08-02-2009, 10:20 PM
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04 ecsb just hit 82k stock tranny never changed fluid EVER the only reason im about to do my tranny is for mods
Old 08-03-2009, 08:14 AM
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I do a lot of towing (7500 lbs) and flush my tranny about every 30K. On my 01 Yukon I had 100k with about 30 towing without a problem. 04 Escalade currently has 75K without a problem. The more heat your trans has and the longer it stays hot--like a 12 hours of towing, the greater the need to have it flushed. However, I have not changed the filters--ever.
Old 08-03-2009, 08:33 AM
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Drop the pan, change the filter, refill fluid. do not do a "flush". you can do this a couple of times to get most of the old dex 3 out.
Old 08-03-2009, 08:51 AM
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tranny flush is a big "no no"

Check out the tank that they use when they're doing the flush. It's not all "new" fluid that goes in. It's everyone else's fluid that has had the same process done.

Just drop the pan, change the filter, and refill. If you wanted your own "flush." change the fluid with the filter two times, and that's about the best. You''ll never really get everything out when you're changing it, there's 2-3qts in the converter.
Old 08-03-2009, 11:11 AM
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What I did was get a hand pump and pump out a quart and then refill with a new quart and drive for a week, then do it again. Do this untill all of the fluid has been swapped, then drop the pan and replace filter and top off. This way your not adding a bunch of new fluid at one time but slowly introducing new stuff. And this way you get almost all new fluid in the tranny without stirring up any gunk.

Last edited by seltaeb; 08-03-2009 at 11:12 AM. Reason: spelling
Old 08-03-2009, 04:12 PM
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ok well I will drop the pan instead and just change 3 - 4 qts for now. Is this a pretty easy job? Also, is there a fill bolt on the transfer case to pour the fluid back in?

Last edited by 050n20s; 08-03-2009 at 04:13 PM. Reason: change response
Old 08-04-2009, 09:33 AM
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A friend has a 99 4x4 Suburban,454,4L80e he got used. His atf was brown and gritty. He got a full flush and all was ok after. I don't know where he had it done. I had done a partial (fluid only) on it earlier;it had a threaded plug on the pan(not stock,I guess).

Is it just a matter of luck?

I did a partial and filter on a 97 Aerostar and it went from slipping on the 3-4 to slipping from a stop. It's fluid was starting to turn brown. I wish I hadn't touched it.
Old 08-04-2009, 10:28 AM
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I think the general agreement is if its turning brown and smells burnt, you definitely shouldn't change it...

The 4l80e, being a stronger transmission, probably faired better just because of its strength.


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