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

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Originally Posted By: 01rangerxl
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.
if you do drop the pan correct you wont spill any.. you want to drop the rear bolts and let it leak slowing and you losen the others. ERIC the Car guys shows how to do this perfect on his Subaru.... I did it on our famly trail blazer and put in new filter and cleaned out the pan and big WASHER looking magnet that was actually stuck to the top of the Trans and not on the bottom of the pan. Put new gasket on.... took like 30 minutes.... not even.
 
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Originally Posted By: LotI
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.
We got a letter in mail from CHEVY as soon as truck hit 80K miles that said it was time for a trans services. However ours came with a factory hitch for towing and we had towed a few small U-Hauls.... So perhaps thats why we got the letter sooner then 100K truck as about 90K now.
 
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Originally Posted By: David1
Originally Posted By: LotI
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.
We got a letter in mail from CHEVY as soon as truck hit 80K miles that said it was time for a trans services. However ours came with a factory hitch for towing and we had towed a few small U-Hauls.... So perhaps thats why we got the letter sooner then 100K truck as about 90K now.
Sounds like they're fishing for revenue...got to pay for recalls, you know. grin
 
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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 [email protected]$$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.
DO NOT DISCONNECT THE BATTERY!!!!!! If you do this, you risk damage to the HVAC actuators. When you power the system back up they go through a check and slam open and shut and this sometimes will lead to a few broken ones. Pull the fuses to the PCM. I think it's fuses 10 and 28. You reset the PCM this way without fear of messing up those actuators. Leave the fuses out for about an hour and put them back in. But I would suggest that you clean the throttle body first so the PCM gets to relearn with a clean throttle body as well. Cleaning the throttle body is a piece of cake, as is changing the plugs on these. Be sure to only use AC DELCO 41-103s. TBs hate Autolites and Bosch Platinum +4s cause preignition. I just did a pan drop and filter change using a Wix filter and a Felpro gasket. Be sure which pan you have before you buy anything. Some TBs have a deep pan, and some have the shallow pan. Also, I started to use DEX VI but decided on Valvoline Max LIFE ATF fully synthetic, since the woman's Toyota performed awesome with it in there. Be sure to not over torque the tranny pan bolts when you reinstall them, or the next time you drop it you'll end up busting one and having to use an EZ Out which is not fun. Trust me lol.
 
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That's rather interesting. I've never had or heard anything slam shut after disconnecting the battery for over 6 hours. That being said, and not to go off topic here, but I'm running Autolite double platinums and the truck pulls like a champ. I don't see what's so special about the NGKs/ACDelcos.
 
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I believe the Autolite double platinums are the only ones besides the Delcos that don't cause problems. Bosch +4s and others are said to really destroy the already bad fuel economy and generally not last as long. I guess "slam" was a poor description for what happens to the actuators, but on trailblazer forums it's explicity said to not disconnect the battery for fear they will be damaged. Better safe than sorry, plus it's easier to just pull 2 fuses.
 
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I'll keep that in mind about the actuators and have a look into it. I haven't heard anything the last two times I pulled the battery cables off - perhaps this only affects certain model years? I don't know. Gas mileage wise, I'm running Euro V rated gas with Mobil 1 ESP Formula 5W-30, which is pretty close to being a 5W-40. I've got a 3.73 rear end, and I average about 22 MPG combined according to my ScanGauge-II. Not too bad, considering I have my share of stop and go, but I use cruise control where possible on much of my highway driving. I also have flow matched injectors along with the Autolite APP-5263's and run Dexron-VI in the transmission with 2 bottles of LGR. Not quite sure how much of a difference in fuel economy Dexron-VI really makes, but I would assume it to be very minor.
 
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Does this vehicle have a drainplug on the torque converter? How we used to do it with the fords is drain the converter via a bolt on it, then drop the pan. You get a lot of fluid this way. Get a pack of chemical resistant gloves also, you will need them. Usually the pan gasket is reusable in ford products, dont know about GM. Get a big can of brake parts cleaner, and some lint free towels to clean the sludge out of the pan, and magnet. Have a new filter ready to go in also. Not a bad job at all.
 
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Originally Posted By: Falcon_LS
That's rather interesting. I've never had or heard anything slam shut after disconnecting the battery for over 6 hours. That being said, and not to go off topic here, but I'm running Autolite double platinums and the truck pulls like a champ. I don't see what's so special about the NGKs/ACDelcos.
I put Denso Platinum TT Spark Plugs in the Trail Blazer and its fine. It did have ACDelco Professional Iridium Spark Plugs in there from factory and 1 of the plugs had a cracked and missing part of the Insulator, I was scared it feel down the plug whole but it came out so easy and i looked with a light and saw nothing.... Im just shocked GM would put a spark plug like that in a truck and we bought that truck NEW.
 
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We have routinely run the Factory OEM ACDelco (by NGK and even before) to far beyond 200k miles without a peep. Over and over and over. A bunch of Silverados and Savanas...
 
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Originally Posted By: threeputtpar
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.
This^^^^
 
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This is what I would do. If the tranny pan has no drain plug, order a pan with a drain plug already installed in it for about $25. Drop the pan, replace the filter and gasket with ac delco or wix, use the new pan with plug in it. Refill with dex 6 or valvoline syn atf spec'd for dex 3 and dex 6 through the dipstick tube to proper level. Let Ur kid drive the car. Then at every motor oil change, drain the tranny fluid out the drain plug and refill at the dipstick tube again. U could do it sooner than every oil change if u want. This is what I did on my daughter's s10 at 100k miles and tranny runs good as new.
 

mrdctaylor

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Done. Dropped the pan last a week ago and put in a new AC Delco filter. Filled with 5 quarts of Super Tech Dex VI. It is shifting great. I'll pump some more out at the next oil change and replace with more new fluid. Everything seems good. Thanks for everyone's advice.
 

mrdctaylor

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Just an update. It is 4-5 months and a couple of thousand miles later. Everything is running great. The TB shifts really well and the pan drop/filter change seems to have introduced no issues.
 
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