Fluid Extractor for GM 8L90

[buster]

I'm considering buying a decent fluid extractor for periodic ATF drains for the Colorado. I've had people tell me to leave it in until 45k miles, which is the OEM drain interval, but others that have had these trucks claim the GM 8 speed likes fresh fluid. One guy that has a 2018, which was a common year for the shudder issue, drained his ATF at 5k miles then every 15k from there on. Never experienced the shudder, which for that year is pretty impressive. He ended up putting a drain plug on the pan, which I'm not going to do.

So, that leaves me with the fluid extractor option vs dropping the pain ever 15k. The truck is under warranty for 6 years, 100k miles. When I approach the 45k mile mark, I'll take it to the dealer for the pan drop. Until then, I'd like to do a pan flush. Most appear to extract a bit over 6 qts.

It's questionable as to whether the 2021 models come factory fill with the Mobil 1 LV HP ATF, or whether they are filled with AC Delco HP LV ATF. Either way, changing it early doesn't seem like a bad idea.

I've never used one but it seems very easy. Any suggestions?

 

[oggb]

which was a common year for the shudder issue, drained his ATF at 5k miles then every 15k from there on. Never experienced the shudder, which for that year is pretty impressive

I've read something somewhere about moisture in the ATF being the culprit for the shudder in most of the 6L80 and later transmissions so your plan of draining it fairly often seems like a good idea.

Mitivac MV7400 gets my vote. Had one for a long time and got a lot of use out of it. Manual hand pump but it's really not bad if you're pumping ATF.

 

[buster]

Thanks, I read that too. Some even went as far as to blame Mobil for the fluid issue saying it was a bad batch or the original Mobil 1 fluid was hydroscopic. I'm not sure if that's true or not.

 

[Brons2]

Why not just drop the pan? Are you afraid the dealer will know that you were in there?

P.S. I did drill a hole in my 6R80 pan, but anyway.

 

[Rand]

HF has some nice mityvac knockoffs.

 

[cos]

Does your Colorado have a dipstick tube?

 

[SuperOldSchool]

I used this one for my Yukon 8l90.
First pan drop at 45k , just did second round at 93k.

OEMTOOLS 24397 9.5 Liter Oil... https://www.amazon.com/dp/B01BW393E2?ref=ppx_pop_mob_ap_share

After second filter/pan drop (week later) I sucked out 5 more qts.

Changed my filter and fluid on 8l90 8 speed today

I followed a YouTube video and changed my 8l90’s filter and fluid today. I had dealer do the first time at 45k. 34k later it’s my turn. I bought a fluid extractor to suck most out of the pan first. The most time consuming step was getting the darn heat shield removed. The rest was easy. I...

www.tahoeyukonforum.com

 

[jhs914]

Thanks, I read that too. Some even went as far as to blame Mobil for the fluid issue saying it was a bad batch or the original Mobil 1 fluid was hydroscopic. I'm not sure if that's true or not.

The original fill for those 8 speed transmissions with the shudder issue was GM Dexron. The blue label Mobil 1 flush fixed the shudder in my 2017 Canyon.

 

[redbone3]

No downside to using an extractor. I read a lot about viscosity loss in motor oil in BITOG, but not so much about ATF. All the gears meshing in an automatic transmission has to cause significant shear.

 

[Snagglefoot]

To the OP, your plans sound similar to what I do on a 6L90 that uses Dex 6. With a 3/8 OD plastic tube, I’m able to pull out 3 quarts which I do once a year, with a pan drop, magnet cleanup and new filter once every five years. The magnetic gets covered with small particles but there was not much in the filter. My transmission has 220,000 miles.

 

[Peted]

To the OP, your plans sound similar to what I do on a 6L90 that uses Dex 6. With a 3/8 OD plastic tube, I’m able to pull out 3 quarts which I do once a year, with a pan drop, magnet cleanup and new filter once every five years. The magnetic gets covered with small particles but there was not much in the filter. My transmission has 220,000 miles.

Do you go through the dipstick? I have never used an extractor before but want to start. I have the 6L80 in my GMC and the 5.3. Not sure an extractor works for the 5.3 though.

 

[Snagglefoot]

Do you go through the dipstick? I have never used an extractor before but want to start. I have the 6L80 in my GMC and the 5.3. Not sure an extractor works for the 5.3 though.

Yes, I lower the 3/8 OD plastic tube into the dipstick tube until it won’t go any further. I’m able to take out 3 quarts. Here is a blurry shot of when I did a pan drop and left the dipstick in place. Your plastic tube will follow the same trajectory, then slump downward to the bottom of the pan. That’s the dipstick on the left. You can also make out the horizontal black filter. You can measure the ID of your dipstick tube and pick up some plastic tubing that can go through it.