Full transmission flush: do it or not?

[dkvasnicka]

As stated in a few other threads, I've bought my 9-7X fairly recently and I have no reliable service records for it (these cars are very rare here in Central Europe and if you want one you either risk & buy it and are willing to spend money or you don't buy it at all and you go buy some boring sensible rational family wagon with a 35 MPG diesel that won't ruin your family when you buy fuel for the glorious > $5/gallon we pay here ). Anyway, my transmission:

• works, no slippage, no RPM spikes on shifts etc.
• the fluid is almost precisely at the top of the HOT area when being checked while hot
• the fluid is very clear - I have problems reading the level on the stick because it's almost transparent
• the fluid doesn't smell burnt
• It seems to me that the pan has been opened in the past and the fluid done - it doesn't seem probable to me that it would be that clear after 90k miles
• No idea whether its already Dex VI or the old III

My question is whether I should do a full flush (the quote for it here is almost $290 which is probably a lot even for the US economy; they use a transmission flush machine called "BG PF5") or just do the the pan drop myself & filter & top it off. I could probably get a lower quote somewhere, this is from a shop that focuses on "amerikas" and that has worked on a few Trailblazers in the past.

The internet is full of horror stories from people who did flushes on transmissions that were running on a single fluid fill for a long time and those then failed almost immediately. I admit I'm afraid but I'd like to hear from experts. Remember, I can assume basically nothing about the past service... go see what I found in my transfer case Also I don't want to potentially spend a lot of money and flush a perfectly OK fluid.

 

[Mounce]

Is the fluid pink/red or literally clear? If it's a clear red/pink then you're good and it's been flushed recently and I wouldn't touch it. If it was just a pan drop it would still be pretty discolored from all of the dirty fluid left in there that didn't get replaced.

If the fluid was old it'd be an awful black color or at least discolored.

 

[HARDTRAILZ]

I would never flush a trans. Never. It sounds like that may have been done though and if so, I would definitely drop the pan and put a fresh filter in. Decent chance the filter will have caught some loosen crud and since it is easy and cheap to to drop in a new filter and few quarts of fresh fluid....I would. Esp since you do not know history for sure.

 

[Boricua SS]

No need to flush. Pan drop & filter change will suffice.

 

[Blckshdw]

I would never flush a trans. Never.

Care to share your reasoning? Could be helpful for future noobs who come across this thread in a search.

 

[HARDTRAILZ]

Care to share your reasoning? Could be helpful for future noobs who come across this thread in a search.

It loosens stuff that won't come out in the flush, but will later and will clog the filter and such after a bit of driving. Then you start getting issues and then failures. You could flush, then drop pan and change filter a couple times after some miles and be ok, but most would never do that it would be pricey. I also do not trust anyplace to touch my truck or any vehicle and some minimum wage jerk-off is not going to learn how to use the flush system on my ride. Not worth the expense or risk and seeing as a simple filter and fluid changes have kept transmissions lasting 100s of 1000s of miles for me and the one flush 15 years ago killed my blazer trans in a few months...I am certain i will never get a flush again.

 

[Tiggerr]

I would never flush a trans. Never. It sounds like that may have been done though and if so, I would definitely drop the pan and put a fresh filter in. Decent chance the filter will have caught some loosen crud and since it is easy and cheap to to drop in a new filter and few quarts of fresh fluid....I would. Esp since you do not know history for sure.

+1 Agree wholeheartedly! Completely unnecessary. Liable to do more harm than good.

 

[dkvasnicka]

Thanks for all the replies, people. I'm glad I was thinking in the right direction and I'm definitely not doing a full flush. However, I was overly optimistic about the color because I was only checking it on the stick. This is how my trans fluid looks like when put on a white piece of plastic:

That definitely has some miles on it. Do you think it's full 90k without a change? Seems like a pan drop & filter change is the best idea and probably better earlier than later.
AFAIK the trans fluid on my Saab 9-5 V6 looked very similar when it had 90k.

 

[Tiggerr]

Looks like some miles on it. Doesn't look bad. Drop the pan, new filter, 5qts. Done.

 

[BlazingTrails]

It has been my understanding that you are only supposed to flush certain transmissions. My 2001 gallant had no filter that could be changed, it had to be flushed because it had a micro mesh filter that was otherwise un serviceable.

If it had a filter change it. Imo

 

[dkvasnicka]

I'll be dropping the pan with front wheels on small ramps. Does anyone have any idea how much additional fluid (over those 5 qts) will that get out?

Of course I'll get the car off the ramps in the end to get accurate reading on the stick.

 

[BlazingTrails]

5 quarts is all you will need. It's really about 4.5 that will come out just pulling the pan.

 

[Paul Bell]

Usually no, dropping the pan, changing the filter and replacing the removed fluid with fresh is all that's needed. BUT looking at your fluid, I would say yes, do a complete flush. This will take 12 quarts-or more.

A nice how-to guide is here: http://www.silveradosierra.com/how-to-articles/how-to-do-a-4l60e-complete-fluid-changeover-filter-t14477.html

 

[Paul Bell]

A euro version, eh? Could you post up photos of the front & rear bumpers?

 

[Mooseman]

1. Never, ever do a flush using a machine. Those are the ones from the horror stories.
2. Doing your own flush can't do any more than what the oil pump in the transmission could do because that is what you're using.
3. Who knows what fluid is in there. Dexron VI is specified for this transmission/year so the previous owner could have used older Dexron III if it wasn't readily available at the time.

May03LT has made a video on doing your own flush. It uses more fluid than just a pan drop and filter but is worth it if you are not sure of the fluid or is really nasty.

https://youtu.be/idRhJW6pPHU

 

[dkvasnicka]

A euro version, eh? Could you post up photos of the front & rear bumpers?

I'm not really sure there was ever any "euro" version... was there? I thought I have the canadian one. Speedo has KPH in big numbers, MPH in small ones. I have all the useless-in-Europe buttons on my rear view mirror. But yeah, the car was officially sold in Italy, no import. So who knows. I also have a retrofitted rear fog lamp, because of european laws that mandate it in many countries. And an european tow hitch. Photos added to my gallery.

May03LT has made a video on doing your own flush. It uses more fluid than just a pan drop and filter but is worth it if you are not sure of the fluid or is really nasty.

https://youtu.be/idRhJW6pPHU

I was thinking about following this one. Probably the same, though. MAY03LT's awesome set of vids was one of the reasons I decided it's "riskable" to buy this vehicle here, BTW...
However I'm still a bit afraid to mess with my trans fluid lines, so I may chicken out and just do a few pan drops with a few hundreds kms between them. Did that on my 9-5 (which had a drain plug ), worked well. Too bad it costs so much to have the aftermarket pan w/ drain plug shipped here.

 

[gmcman]

There's a small plate next to the pan mounted on the trans case on the drivers side. Loosen the two 13 mm bolts but don't remove the plate..makes it a little easier removing the pan.

 

[Machoman]

Can someone post a picture of where the pan is located? I was trying to located is last week when changing my oil and failed.

 

[Blckshdw]

This should help... Skip ahead to 3:35

https://www.youtube.com/watch?v=qvXzYlTHvow&t=3m34s

 

[MAY03LT]

The internet is full of horror stories from people who did flushes on transmissions that were running on a single fluid fill for a long time and those then failed almost immediately.

I've read/heard my share of those stories too but in all my years doing this I have never experienced it myself. And I've serviced hundreds if not thousands of some of the nastiest transmissions out there, even ones with water/coolant contamination. Personally I think the people that did have a failure only got the flush to try to fix an issue and when the flush didn't work, it was the flushes fault (of course). Put it this way, my 98 pickup with the 4l80e is original fluid at 170K and I'm not worried about flushing it. And by flush, I mean our DIY way, not using a machine.

Also if anyone watched the vid that was linked, later I tried a different method when I did my Tahoe (also 4l60e) which made the job easier since it was only me that time. I followed a tip from gmcman where you only pump out a couple quarts at a time and it worked great. I haven't had time to add annotations to that Envoy video but the Tahoe way is the way that I do them now.

 

[Machoman]

MAYLT03,

I have been watching this video over and over for two weeks now. Would this job be possible with one person?

 

[hockeyman]

MAYLT03,

I have been watching this video over and over for two weeks now. Would this job be possible with one person?

I sure hope so since I'll be doing it soon, without anyone to help. The video is awesome and I'm glad I've watched it. That damn little clip at the radiator connection would have probably been overlooked. I also know to buy a 1/2" ID clear hose. Thank you, MAY03LT!

 

[Mooseman]

I linked the second easier method in my post (I couldn't link directly, gave me an error that the owner of the vid doesn't allow playing on other sites)

I agree. My TB had over 210k Km and the fluid was really nasty. I flushed it myself, 70k and 4 years later, no issues and I'm pretty sure I'm running the original tranny.

 

[BrianF]

I am a big proponent to doing the fluid exchange. I found the method on the OS. It was easy, I mean so easy I was able to do it...... Did not spill a drop when the pan came off. So easy that the pan gasket was wiped down and not even removed from the pan. There is debate on whether to even bother to change the filter. The dealer said they do some sort of "pressure differential" to see if it is plugged. Well it is easy to change and cheap and the pan gasket is reusable so it is painless.

I used several feet of clear tubing off the output line and did several pump outs. It all went into a fairly clear jug and it was interesting to see how dark it actually was.

The hardest part of the job was re-attaching the output line to the rad. Ok so I leaked some a bit of atf doing that.

It is cheap insurance for an expensive component.

 

[Mooseman]

That is the correct terminology. Fluid exchange, not a flush.

 

[dkvasnicka]

Did the pan drop today. I think the world has seen worse ATFs...

Does this look like 90k miles? The gasket looked like paper (do any aftermarket gaskets come in this form?) and the bolts were surprisingly lightly torqued.

 

[Mounce]

The fluid looks about on par with well treated (easy driven) 90k fluid, off-red / light brown. But that's not to say that it wasn't black and the people before you changed it but didn't get all of the old fluid out thus contaminating the fresh fluid with old.

 

[HARDTRAILZ]

Does not look too shabby. Cant remember what material my gasket was offhand though.

 

[dkvasnicka]

Also the manual says 4.7L would come out but I only got 4L out. However when checking the fluid while hot it was within the HOT area. WTF?

What difference in volume does the area on the dipstick represent?

 

[HARDTRAILZ]

I would not even think twice about it if it is reading in the right spot.

 

[rtliquid]

Are there any tricks to keeping the gasket aligned as you're raising the pan back up and starting the bolts? I haven't done one since the mid-80's and I just remember the gasket kept shifting and I couldn't keep it aligned with the pan holes while trying to bolt it back up. I finally ran a bead of gasket sealer around the pan and placed the gasket down on it. That ended up being one horrific mess because things still shifted and, of course, the sealant oozed out all over me once I started tightening things up.

 

[Blckshdw]

I'd imagine if it came down to it, a well placed piece of painters tape or 2 could hold opposite sides of the gasket in place until you were able to get the bolts started, then take them off before snugging the pan up.

 

[Tiggerr]

Are there any tricks to keeping the gasket aligned as you're raising the pan back up and starting the bolts? I haven't done one since the mid-80's and I just remember the gasket kept shifting and I couldn't keep it aligned with the pan holes while trying to bolt it back up. I finally ran a bead of gasket sealer around the pan and placed the gasket down on it. That ended up being one horrific mess because things still shifted and, of course, the sealant oozed out all over me once I started tightening things up.

I use high-tack gasket adhesive. Think permatex makes it. It's like a thin reddish glue. Brush on the flange give it a few to tack up. Stick gasket to pan. Viola! No slippage. Used that stuff since the 80's. All I ever use on gaskets. Usually insures that the next time the gasket will stick to the pan, valve cover, oil pan, etc and not the engine, trans etc. easier to remove that way, instead of trying to scrape gasket off hard to get to places.

http://m.autozone.com/autozone-mobile/en/accessories/Permatex-4-oz-brush-top-can-High-Tack-gasket-sealant/_/N-25c6?location=&id=554063

 

[dkvasnicka]

Are there any tricks to keeping the gasket aligned as you're raising the pan back up and starting the bolts? I haven't done one since the mid-80's and I just remember the gasket kept shifting and I couldn't keep it aligned with the pan holes while trying to bolt it back up. I finally ran a bead of gasket sealer around the pan and placed the gasket down on it. That ended up being one horrific mess because things still shifted and, of course, the sealant oozed out all over me once I started tightening things up.

Had this problem with the rear diff but not with the trans. I put two bolts into two of the corners and put it back while holding them in. I then tightened them very very lightly to make sure I don't get a "facepan" Then I started putting other bolts in, doing it in a star fashion, as if I was doing wheel bolts. Did that with a cordless electric screwdriver and then did final tightening with a ratchet.

 

[gmcman]

Did you loosen the metal bracket next to the pan? For me it makes it easier to position the pan....two 13MM bots, loosen enough to move bracket but don't remove.

If you don't have a torque wrench then just lightly tighten, go around the pan about 3 times as the gasket compresses. Torque is about 100 inch pounds.

 

[Mooseman]

Usually, the bolt holes in the gasket are smaller than the bolts so they stay in there holding the gasket in place with a few bolts. MAY03LT has used a little weatherstripping adhesive in the corners.

I don't think it was necessary to goop the whole thing though.