New-to-me 2002 Trailblazer w/152K mi. Change ATF?

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I had started a topic in a different sub-forum and got into the ATF stuff a little bit. However, it was off-topic so I decided to post something here instead. Here is my dilemma:

My parents just gave my daughter their 2002 Chevrolet Trailblazer with the i6. It has 152K miles. It has been well-maintained EXCEPT that my dad never does transmission fluid changes on his vehicles. Ever. The transmission shifts fine as far as I can tell. The fluid is dark, but doesn't smell burnt.

Basically, I've read lots of conflicting advice on the internet. Many people say that in a transmission that old/high mileage that it is safest to leave it alone. Others say the opposite. I just don't want to create a headache for myself a few months before my daughter goes to college. I don't want a big expense. Of course, I want to do what is best for the car too. I change my ATF in my other vehicles every 30K miles.

As I see it, I have 5 courses of action.

1) Do nothing and let it ride.

2) Do a flush. This seems like the most risky option.

3) Have my mechanic do a pan drop, replace the filter, and replace the 5 qts of fluid that are supposed to come out of the pan. I'm not particularly comfortable doing a pan drop myself.

4) Using my hand pump, get as much as I can out. Drive around. Do a fluid swap again. This way I'll get most of the fluid out quickly and won't have to drop the pan. I've read that these filters regularly clog and it is probably a waste of time to drop the pan and change them. I know my Toyota only has a screen, so filters must not be THAT necessary.

5) Use my pump and replace the fluid gradually (say 1 qt every 1000 or 3000 miles).

It specs DexIII and I'd bought several quarts of Mobil 1, which is what I have used for years on my Tacoma that specs DexIII. If I do end up replacing the fluid in some fashion, is there a better choice for a high mileage tranny?

In a nutshell, I'm confused and am having trouble telling fact from fiction. There *ARE* quite a few horror stories about people changing the fluid in their (supposedly) perfectly fine transmission only to have it fail shortly thereafter. There are lots of people that say this is a coincidence, but that seems a bit cavalier to me. There wouldn't be that many examples of failures if there weren't some truth to it.

Anyway.....HELP! Sorry for posting again. I'm just trying to make the best decision for this vehicle and it does not seem at all clear cut. I've searched and read everything I could find on the subject...and it hasn't really helped. Maybe there are those that have done this exact thing to this transmission and can comment.
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If you have no knowledge of the trans filter, it needs to be changed. A flush is the easiest and best use of ATF.

Most people ignore their transmissions until they hear something odd and then want a flush to fix it. So they get a flush and the trans fails shortly after.

Install a Magnefine inline filter. It will catch up any crud that gets loosened.

I use only Amsoil ATF.
 
Pan drop with filter change would be my suggestion. It would be a partial change and introduce some new fluid. Dex6 superceeds Dex3, any dex6 would be fine as the formula for certification should result in high quality fluid. Then after 30k I would do the same and so on.
 
If the trans is a 4L60E, it might have a drain plug. That would simplify option 4.

I would eventually get the filter changed. The vehicle is 52,000 miles past what the manual probably suggests for that service.

You have the benefit of knowing the vehicle's service history and how it was driven. Does either of your parents drive in a way that makes you worry about the trans?
 
3! I brought a slipping 4T60 back to life by cleaning it out and getting a new filter on there. It was then able to get more pressure to apply the clutches better.

The theory that you want clutch grit floating around to help the clutches is an old wive's tale.

I would have him do it with generic Dex3 the first time around then consider other options like your m1.

Can your daughter do the pan drop? There's not much to it; hanging the pan back up gingerly takes more talent. It's always good to involve kids with cars, helps them take better care of them.
 
That is the trans so I'll get under it and check for a drain plug. Ii am pretty sure it doesn't have one though. My mom drives it easy. It has never towed a trailer.
 
If the fluid does not smell burnt, I would exercise your option (3). Have your mechanic drop the pan, change the filter, and replace ATF as needed. You really need to do no further. I believe your user's manual supports this option.
As mentioned above, the flush is no miracle cure, and your car does not need it.
 
Another vote for #3, then #4 every 30000 miles.

Definitely do NOT flush it, IMO.

I agree with using the same Dex 3 that is in it already.
 
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Use the hand pump and get all you can out of the pan. Get under there and take the pan off (no fluid in it so you wont get a shower of ATF) and replace the filter. I suggest a filter kit from Autozone as that was the only one that had a rubber gasket instead of a cork one in my situation. You may even be able to reuse the original gasket if it's one with rubber over a metal frame.

Fill it back up and drive it for 5k miles, and then pump out as much as you can again and refill.

Pump and fill every 30k miles after that.

Edit: Any fluid will likely work the same as any other. Dex 3 from Walmart, any Dex 6, MaxLife, or Amsoil. My personal favorite is Wolf's Head Universal as it's a full syn and I can get it for $4.25 a quart.
 
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Originally Posted By: Kuato
Another vote for #3, then #4 every 30000 miles.

Definitely do NOT flush it, IMO.

I agree with using the same Dex 3 that is in it already.


Pure BUNK on the "no flush" comment.
 
Doesn't that model have a drain plug? If so start with all few drain and fills with mineral based dex/merc with 1,000 miles between them. After 3,000 miles change the filter and switch over to Maxlife or dex 6.
 
Originally Posted By: Donald
Originally Posted By: Kuato
Another vote for #3, then #4 every 30000 miles.

Definitely do NOT flush it, IMO.

I agree with using the same Dex 3 that is in it already.


Pure BUNK on the "no flush" comment.


Please explain why. For my part, I have seen and heard of numerous transmission failures after a flush when the unit had over 100k on it. That's my experience, what's yours?
 
Originally Posted By: Donald
Originally Posted By: Kuato
Another vote for #3, then #4 every 30000 miles.

Definitely do NOT flush it, IMO.

I agree with using the same Dex 3 that is in it already.


Pure BUNK on the "no flush" comment.


Big difference between flush, drain/refill, and total fluid exchange.
Flush means using a machine to force solvent through the trans trying to clean it prior to new fluid but does more harm.
Drain/refill means draining and adding fluid repeatedly in certain intervals if you have a trans dipstick.
Fluid exchange means disconnecting the ATF cooler lines, connecting them to two tanks holding fresh ATF and old ATF and using the trans ATF pump to exchange the fluid. Then you would change the filter, then check the fluid level which is useful for cars that don't have a dipstick.
 
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I prefer to do a pan drop for 2 reasons:
1. There is usually some stuff that sticks to the pan, and never gets filtered out.
2. If something is wrong with the transmission, you might see it in the transmission pan.

OEM gaskets are best. The ones found in "Gasket and filter" kits don't always last. You might consider an OEM filter, many replacement filters are cheaply made.
 
Use a hand pump to get ~2 quarts of fluid out the dipstick tube and pour in a quality Dexron-VI. Drive it around and get a feel for how the transmission shifts. If you notice improvement, I would drop the pan, clean the magnet, replace the filter and refill with 5 quarts of Dexron-VI (assuming you have the deep pan). You might wish to substitute a quart of Dexron-VI for a quart of LubeGard Red (available on Amazon for ~$21). That way you'll get 7 quarts of fresh fluid in there. Pull the battery cables off and reset the PCM, so shift patterns can be relearned with the new fluid. Drive ~1,500 miles and repeat.

I strongly recommend you get a decent cooler in there, however. The one in the radiator is a half-@$$ed effort on GM's behalf - based on my research the 4L60-E is designed around a top operating temperature of 200 F. The thermostat on our trucks is rated at 195 F and since the cooler allows ATF to match coolant temperatures, with high ambient temperatures you're looking at 200+ F.
 
Originally Posted By: Falcon_LS
Use a hand pump to get ~2 quarts of fluid out the dipstick tube and pour in a quality Dexron-VI. Drive it around and get a feel for how the transmission shifts. If you notice improvement, I would drop the pan, clean the magnet, replace the filter and refill with 5 quarts of Dexron-VI (assuming you have the deep pan). You might wish to substitute a quart of Dexron-VI for a quart of LubeGard Red (available on Amazon for ~$21). That way you'll get 7 quarts of fresh fluid in there. Pull the battery cables off and reset the PCM, so shift patterns can be relearned with the new fluid. Drive ~1,500 miles and repeat.

I strongly recommend you get a decent cooler in there, however. The one in the radiator is a half-@$$ed effort on GM's behalf - based on my research the 4L60-E is designed around a top operating temperature of 200 F. The thermostat on our trucks is rated at 195 F and since the cooler allows ATF to match coolant temperatures, with high ambient temperatures you're looking at 200+ F.


I put in both Lubgaurd RED and the Lubegaurd that many use in Honda and actually says GM on the bottle.

but look what AMAZON says. Strange huh? The ATP Friction Modifier came back as recomded and says Chevy Trucks approved.

flau8o.jpg



I put ATP AT-203 Synthetic Automatic Transmission Fluid Friction Modifier in our 2007 Trail blazer when I dropped the pan and clened the magnet and put new Castrol Trans fluid the syn blend for Chevy Truck...
First I did the drop pan and put new fluid..and it felt better but once I put ATP in.
WOW.

it was much better

also look on you tube and look what Scotty Kilmer as to say about just about ALL ATP products.

even there multi syn Trans fluid made by ATP.
 
Time for a change.

GM's normal service is 100k miles. Severe is 50k miles. This is with drain/refill service so there's still more than half old fluid in there.

Have your mechanic drop the pan and clean out the sludge and magnet.
 
As it is not exhibiting any problems . . .

I'd do a pan drop filter and fluid top off with Dex VI.

Then after 5k, I'd do complete fluid exchange with Dex VI.

After that, every 30k on changes should be fine.

I'll only defer fluid changes on a high-mileage box if it's experiencing issues, as it's likely too late at that point anyway and fluid isn't going to fix it. But I know opinions vary wildly on this point.
 
If it were mine...flush and filter change ASAP. I like clean ATF.

There is some risk on a higher mileage, neglected unit, but IMO if it has problems afterwards, they were coming soon anyways.

I bought a $950 Explorer with the original trans, unknown maintenance, and did a flush at 150K miles, shortly after purchase. No issues. Shifted the same afterwards (no issues beforehand).

Pan drops aren't that bad, but not really fun to do with the vehicle on the ground. If you can do an oil change, you can do a pan drop/filter change, it just isn't much fun with the vehicle on the ground, and you might find out what old ATF tastes like.
 
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