Transmission Fluid Flush & Power Steering Fluid Flush

[chipjumper]

I did hours of searching and could not find anything definitive for this matter. I keep reading how some guys say to pull the drivers side tube and some say the passenger side tube. Then they do not indicate if you should attach a piece of rubber tubing to the metal tube or directly to the transmission.

To end this pitiful nonsense, I took some photos today of me doing this. For starters, I strongly recommend that you spend the $10 for the Hayden transmission adapter part #397 as this works with almost every GM vehicle I've done these flushes on.

Transmission:
1. Remove transmission pan, clean the magnet, and replace filter. The TB is the easiest GM truck I've ever done this on.
2. Remove the c-clip from the LEFT SIDE (Drivers Side) port on the bottom of the radiator.
3. Pull out the metal transmission tubing - it may drip a little.
4. Insert the brass Hayden adapter and replace the c-clip you just removed.
5. Attach a vinyl hose to the brass adapter and secure the other end into a bucket (it will fly out if you don't secure it).
6. Add five quarts to the transmission via a funnel and dipstick tube.
7. Start up the engine and run it until the fluid color changes - DO NOT RUN OUT OF FLUID - have someone fill it while it is running.
8. Pull the c-clip, re-attach the metal transmission tubing, re-install c-clip.
9. Check fluid level in transmission; add as necessary. Go for a test drive and re-check fluid.

*Note - If doing this alone, run the engine incrementally so you can stop it and refill the transmission sump.


My power steering fluid was almost black. I flushed it as noted below and shown in the bottom photo:

Power Steering:
1. Suck fluid out of the reservoir via a turkey baster or preferably use a Mity-Vac pump to suck it all out.
2. Find the rubber hoses that attach to the power steering fluid cooler at the underside of the front bumper (see photo).
3. Unclamp the bottom-most and most easily accessible hose and pull the rubber hose tubing off.
4. Attach a piece of vinyl tubing directly onto the metal cooler nipple - no clamp necessary.
5. Fill the reservoir with fresh fluid (note that the rubber tubing you disconnected will slowly drip fresh fluid - no big deal).
6. Turn the wheel to the left and to the right several times; I did about eight times left/right and then refilled reservoir.
7. Continue doing this until the fluid coming out of the tube is clear.
8. Re-attach the rubber tubing and re-clamp.
9. Check fluid level.

I went through about 2 qts of power steering fluid. Gallon of Valvoline cost me like $17 at Advance.

 

[IllogicTC]

This is some good stuff right here.

As a reminder to people doing this solo, to give you greater control over the engine's "pumping time," hold the accelerator pedal all the way in and then manually crank it. Holding the pedal all the way down makes it enter "clear flooding" mode, and thus shouldn't provide spark, just turn the engine with the starter.

 

[chipjumper]

Good call IllogicTC - I never knew about such mode. I've done this about five times to my GM fleet and I use one of those long black transmission funnels and fill it at the rate it is flowing out of the vinyl tubing. Cranking it without spark would make it much easier then me wiping out on my wet garage floor as I race back to the cockpit to shut off the running engine.

One more point - I noticed that some folks like to hook up the vinyl tubing to the passenger side tubing. That will work too BUT you are leaving old fluid in the transmission cooler (inside the radiator). Using the Hayden brass fitting, you are also flushing the fluid out of the trans cooler.

 

[marinegrunt]

I agree...very good stuff. I did the same thing as you last year in searching everywhere and getting different advice. I too bought the adapter to save the headache of trying to rig something up.

I had no idea about the "clear flooding" mode. I was running back and forth like crazy with my heart rate a bit elevated the whole time.

This post will save a lot of people a lot of time and grief. Great job!

 

[Mooseman]

This is basically the same method I use except I first disconnect the pipe and then start the engine to pump out all the old fluid from the tranny. It empties the pan and may even pump some out of the torque converter. Cuts down on the mess when taking the pan off. As soon as the fluid output sputters, shut down the engine. The pump will not be damaged doing this.

 

[dkvasnicka]

Did the PS part of this today and I have a few observations / suggestions.

First, "note that the rubber tubing you disconnected will slowly drip fresh fluid - no big deal" was quite far from reality in my case. The moment I poured the new fluid into the reservoir it started running out of the tubing, pretty fast. I had to plug it because otherwise I think the whole procedure would be excercise in futility. YMMV but I don't see how it could not start running out immediately.

Second, it took just about four or five turns lock-to-lock for me to see clear green fluid coming out (was changing from dino to synth Valvoline PS fluid).

Third, the attached PDF came in pretty handy.

Hope it helps.

 

[BrianF]

Like Mooseman said, pump out the pan first. I never had one drop leave the pan when I did it this way. There was next to nothing left in the pan when I dropped it.

 

[dkvasnicka]

As for trans, for me the biggest nuisance wasn't the fluid in the pan (managed not to spill it) but the endless droplets on the valve body that rained down after I took down the pan... Is this a non-issue when pumping the fluid out first?
The body of the trans is bigger than my drain pan(s) so it was quite a game to catch everything Dorman pan with a drain plug is already waiting in my parts stash

 

[Mooseman]

Two ways to avoid that. Lay down a tarp or large cardboard or like I have is a large flat pan. Kinda looks like a giant cookie sheet. Great to also hold bolts and tools.

I've seen plastic ones like this though. These get bent out of shape.

 

[5xBuckman]

So here's a question regarding the transmission fluid. If what I think has happened on the TB I bought as a fixer (burnt valve) then I'm pulling the engine.

If, while I have the engine out, could I drop the trans pan, change the filter....and then remove the torque converter, drain it...then reinstall? Then just fill with fresh fluid and call it good?

I know how to properly seat a TC in the pump.

 

[AtlWrk]

If you're comfortable pulling the TC than this sounds like a good plan. There will always be some trapped fluid throughout the trans and cooler lines, etc. but this will get you further than a lot of other drain/pump methods.

Side note: This would also give you the opportunity to check the TC/pump seal--there was a TSB for 2006 models that burrs on the TC shaft nicked some seals causing minor dripping. I know yours is a 2005 but can't hurt to look while you have it out.

 

[5xBuckman]

I have determined the engine has valve issues, so out it comes. I will likely proceed with thed trans fluid as above.

Thanks!