02 GMC Envoy - To flush or to drain?

[byez]

Its the middle of winter here and I really don't feel like dropping the pan and replacing the tranny filter. The ATF fluid has not been changed since leaving the factory and its sitting around 150,000 kilometers.

Its my brother's car and he is worried. Should I
a. leave the fluid in
b. drain and fill with Amsoil ATF
c. drain and fill with X brand ATF
d. wait till summer and drop the pan and replace filter
e. do a flush at a drive through lube

 

[GMBoy]

Is there even a drain plug on the pan? If so, then yes you'll be ok just draining and refilling until the warm weather when you can drop the pan and change the filter. Of course, with winter coming and its not your truck anyhow - let him take it somewhere and get the whole thing flushed and the filter changed.

 

[Whitewolf]

My advice is as follows.
If he gets it flushed make sure that he knows what it's being flushed with (just ATF, no solvents).
Really what he should do as a minimum is a drain and refill with DEXRON-VI and then repeat the process after a few thousand miles. It's best to do that more than once.

 

[Tempest]

Do an ARX run with current fluid.

Then flush/fill with DexVI through the cooler lines to get the most old fluid that you can. Amsoil should be fine, too, just more expensive.

 

[02zx9r]

B then D

 

[Donald]

With 150,000 km on the current fluid I would be uncomfortable with introducing new fluid via a drain or flush until I dropped the pan and cleaned it and replaced the filter. New fluid will start to clean up crud in the tranny and could possibly clog the filter. Also I would prefer to wipe off the crud that had settled on the bottom of the pan rather than have new ATF clean it up.

 

[PT1]

Take it to a local trans shop and drop and clean the pan and replace the filter and re-fill with DEXVI. Then after 5000 miles drain and refill with drain bolt or fluid extractor. Do this drain-fill 3 or 4 times with every engine OCI and you should be ok unless the trans is showing issues now. You should be sure to drain when the fluid is hot so you will have most of the contamination suspended in the fluid. If the pan has a drain bolt make certain to heat it lightly as it will have factory threadlocker on it. I would not flush at this stage.

 

[JTK]

byez, At that age and mileage, I would do a pumpout, refill and then a pan drop & cleaning some time later. There is a dipstick, but no factory pan drain plug on this 4L60E. When I owned a 2005 Trailblazer, I did a series of pump outs through the cooler line and refilled through the dipstick tube. All GM T360 chassis (Envoy,Trailblazer..etc) use the 4L60E transmission. The cooler lines are plumbed solid (no rubber) so they are kind of a PITA to work with. On top of that, the cooler lines are plugged into the radiator tank cooler with push-lock fittings which are a joy to work with. You have to slide back the protective collar, carefully pry off the circlip with a pick, push in HARD and then pull back out. I also found out that at idle, this trans will pump out approx a gallon of ATF in ~10sec, so you need a helper to start/stop the engine, while you are underneath, supervising the pump out.

 

[byez]

Is there a way to extract fluid from the dipstick tube? Not the best engineering to have no drain bolt imo.

 

[XS650]

Originally Posted By: byez
Is there a way to extract fluid from the dipstick tube? Not the best engineering to have no drain bolt imo.


That's not engineering, that's bean counting.

 

[JTK]

Originally Posted By: byez
Is there a way to extract fluid from the dipstick tube? Not the best engineering to have no drain bolt imo.


I never tried it on my Trailblazer, but I'm sure it would work. I've done ATF dipstick tube suck outs on other vehicles. You usually get 2-4qts out per session that way.

 

[PT1]

You will get 2 qts out of the 4L60E dipstick tube with a fluid extractor. When you do the pan drop you can modify the end of the dipstick tube so your fluid extractor tube will fit to the bottom of the pan and you can then get 4-5 quarts out.