98 K1500 4l60E TRANNY FLUSH/OVERFUL

[ChrisR36]

Ive bought this truck a few months ago, motor just went out and Im in the works of obtaining and putting a new one in. I should be done by next weekend if all goes to plan. Anyways, Im looking to flush the 4L60E and ive seen a few other threads, it seems pretty straight forward other than that my tranny has been overfilled, the fluid is still dark reddish, but when the tranny is cold, it seems he had overfilled it to 2, almost 3 times the level it should be?! Is this a sign of something? With the tranny overfilled how should I go about flushing it? the same way? I plan to also drop the pan and change the filter as well. Also this tranny should take DEX VI right? Ive been looking at prices, most are CRAZY! I see this on amazon, only 20$ a gallon. Is it anygood ?

Genuine GM Fluid 88861954 DEXRON-VI Automatic Transmission Fluid - 1 Gallon

https://www.amazon.com/Genuine-GM-8...UTF8&qid=1503668345&sr=1-9&keywords=DEXRON-VI

Thanks, Chris

 

[df2x4]

No idea what's up with the overfill, but for what it's worth I would NOT do any kind of a flush on your transmission. A drain and refill with a new filter will be fine.

Also you really don't need GM Dex 6, the parts store Dex 3 equivalent fluid is just fine and much cheaper.

 

[El Tigre]

Dex VI is the only fluid GM specifies for it's transmissions. Mine responded quite well to it,and it can be gotten from amazon.com very reasonably. Unclear why anyone would still recommend Dex III when it has had so many problems associated with it.
http://www.gmls4.com/index.php?topic=604.0

 

[df2x4]

Dex VI is the only fluid GM specifies for it's transmissions. Mine responded quite well to it,and it can be gotten from amazon.com very reasonably. Unclear why anyone would still recommend Dex III when it has had so many problems associated with it.
http://www.gmls4.com/index.php?topic=604.0

It's the only fluid GM specifies because it's the only one they license and make a profit on currently. There is absolutely no reason that putting Dex 3 in a transmission that called for it and ran it for 20 years is going to do any damage as long as you follow a regular maintenance schedule and change it once in a while. I'm sure Dex 6 is a "better" fluid, and if I owned a 2006 or newer trans that called for it originally that's what I would use. These old transmissions do not care though.

 

[El Tigre]

My "old" 4L60-E's sure seem to like it. Both run cooler,and operate better than they ever did w/Dex III... Since one can find it for the same (or,close to) the same price. Why not use it...

 

[df2x4]

My "old" 4L60-E's sure seem to like it. Both run cooler,and operate better than they ever did w/Dex III... Since one can find it for the same (or,close to) the same price. Why not use it...

Because you don't need it.

I'd love to see some hard data about the cooler operating temps you've experienced, I've never seen anyone else mention any gains from switching to Dex 6.

 

[El Tigre]

To each his own,suit yourself. Dex VI is superior to Dex III in every way. Probably why GM spent the time,and resources to develop it.
Implying that Dex III is just as good simply isn't true. Will it work? Sure... Is it recommended? Not by any credible industry source that I can find...
http://www.impalassforum.com/vBulletin/5-drivetrain/256489-best-performance-atf.html

 

[df2x4]

I read through both of those threads you linked (and many others on the subject) and the only "credible industry source" I can find is that tech bulletin from GM that's been posted all over the place. And like I said earlier, they make and/or license the stuff. Of course they want you to use it. I also see a lot of people agreeing with my point of view.

I agree with you on one thing though, to each his own. If you feel like spending the extra money on Dex 6 is worth it for pre '06 automatics then by all means, go ahead. Personally I don't see the need. Neither one is going to hurt anything.

EDIT - I also never said or implied that Dex 3 was "just as good" as Dex 6. My only point was that it wasn't necessary for the OP.

 

[El Tigre]

How is it "extra" money? Last gallon of Dex VI that I purchased was around $20,and have seen quarts for a little over $5 each if one shops around a little.

 

[mistaake]

I'm pretty sure every GMT400 out there came with something older than Dex 6, and so the regular DexIII/Merc stuff from the auto parts store is fine. However, Dex6 is an upgrade, and there is no disadvantage to switching to the superior fluid. Power flushes really are kind of a bad idea, a drain&fill with filter change, and if you really want, a few more drain&fills, are plenty good enough. Dorman and some other companies make easy to find transmission pans with drain plugs, if you so desire to change the fluid more often.