Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum banner

1 - 20 of 85 Posts

·
Registered
Joined
·
1 Posts
Discussion Starter · #1 ·
I have an 03 trailblazer with the 4.2 vortec inline 6, idk much about transmissions but mine is just acting goofy. I have 238,801 on the odometer and I need to change the fluid in the tranny, just looking for tips when changing fluid and filter.
 

·
Registered
2004 chevy trailblazer_lt
Joined
·
1,040 Posts
I would suggest doing a pan drop and filter change. Do not do a fluid exchange that is offered at many quick lube places, chain auto repair shops, and some dealership service departments.

Jack your TrailBlazer up and place it on jackstands.

Get a large oil pan that is able to hold 7 - 10 quarts of fluid, and place it under the transmission's oil pan. Then begin to loosen the transmission oil pan bolts, with the loosest bolts towards the front of the car and keep the back pan bolts barely loose. When you get to the point where the front pan bolts are essentially out, see if you can grab hold of the pan lip and pull it down. WATCH OUT because transmission fluid will begin to pour out all over you if you are not careful. Now, begin removing the bolts from the sides of the transmission oil pan, and as you do this, the pan will tilt down in front more and fluid will keep flowing out. When you have all of those bolts out, move to the rear of the pan and begin to loosen those bolts even more. Again, WATCH OUT for more flowing fluid.

After much fluid has flowed out of the oil pan and into the drain pain, put one hand under the transmission oil pan to steady it, and with your other hand, finish removing the rearmost pan bolts. Then, all of a sudden, the pan will be free and supported by your one hand. Now, using you other hand, grab the pan and pour the rest of the fluid into the drain pan.

Leaving the drain pan in place to catch all the drips, remove the transmission filter by pulling down on it, and place it in the drain pan. Now, remove the new transmission filter from the box and install it. Now, here is a hint. All the books say to remove the filter seal from the transmission valve body and install a new one. Well, I normally leave the old one in, and push the new filter into it and make sure the filter is in there snug and tight.

Now figure something (a large piece of cardboard, newspapers, etc.) to place under the transmission valve body to catch all the drips, and move the drain pan out of the way. Now you will want to clean out the inside bottom of the oil pan. Use paper towels, carb cleaner, brake cleaner, etc., and clean off the magnet and put the magnet back in the pan.

Pro Tip: The factory installed transmission oil pan gasket is a high quality gasket and can be reused many, many times, so use it, and do not throw it away. You can throw the replacement gasket that comes with your filter away when you are finished.

Pro Tip: Before doing all this work, tray and get under your TrailBlazer and measure the depth of the oil pan. There are 2 different filters which can be used. One for a shallow depth pan, and one for a deeper depth pan. The shallow pan measures about 2 & 1/4 inches deep from the pan flange, and the deeper pan measures about 2 & 7/8 inches deep from the pan flange. Now, armed with this information you can purchase the correct transmission oil filter!

Pro Tip: Dexron III, the fluid specified for your transmission has been discontinued and is superseded by Dexron VI, which is backward compatible with all previous Dexron AT fluids. Dexron VI is a much better fluid than Dexron III.

You will also need to purchase at least 4 quarts of Dexron VI transmission fluid in order to replace the fluid that you drained from the transmission. If I were you, I would purchase 6 quarts of Dexron VI just to be safe.

Now if you are planning on keeping your TrailBlazer for quite awhile and are planning on changing the transmission fluid again, consider purchasing a Dorman transmission oil pan with drain plug, Part Number 265-811 (about $32.00 from rockauto.com). This way, the next time you want to drain the transmission fluid, you can just remove the drain plug from the pan. If you do go this route, you will need to use a transmission filter for the deep pan (such as Purolator P1267 filter).

OK, so now reinstall either the new Dorman pan, or the cleaned factory pan and tighten the transmission oil pan bolts to 13 foot-lbs. Take the TrailBlazer down off the jackstands, and add at least 3 quarts of the Dexron VI to the transmission through the dipstick tube. Now start the engine and check the transmission dipstick. Add Dexron VI until the fluid comes up to the cold mark on the dipstick. Now sit in the driver's seat, place the parking brake on and with your foot on the brake pedal, shift your transmission through all the gears and then back to park and recheck your fluid level.

That's all there is to do it.
 

·
Registered
2003 Chevy Trailblazer LT
Joined
·
264 Posts
I would suggest doing a pan drop and filter change. Do not do a fluid exchange that is offered at many quick lube places, chain auto repair shops, and some dealership service departments.

Jack your TrailBlazer up and place it on jackstands.

Get a large oil pan that is able to hold 7 - 10 quarts of fluid, and place it under the transmission's oil pan. Then begin to loosen the transmission oil pan bolts, with the loosest bolts towards the front of the car and keep the back pan bolts barely loose. When you get to the point where the front pan bolts are essentially out, see if you can grab hold of the pan lip and pull it down. WATCH OUT because transmission fluid will begin to pour out all over you if you are not careful. Now, begin removing the bolts from the sides of the transmission oil pan, and as you do this, the pan will tilt down in front more and fluid will keep flowing out. When you have all of those bolts out, move to the rear of the pan and begin to loosen those bolts even more. Again, WATCH OUT for more flowing fluid.

After much fluid has flowed out of the oil pan and into the drain pain, put one hand under the transmission oil pan to steady it, and with your other hand, finish removing the rearmost pan bolts. Then, all of a sudden, the pan will be free and supported by your one hand. Now, using you other hand, grab the pan and pour the rest of the fluid into the drain pan.

Leaving the drain pan in place to catch all the drips, remove the transmission filter by pulling down on it, and place it in the drain pan. Now, remove the new transmission filter from the box and install it. Now, here is a hint. All the books say to remove the filter seal from the transmission valve body and install a new one. Well, I normally leave the old one in, and push the new filter into it and make sure the filter is in there snug and tight.

Now figure something (a large piece of cardboard, newspapers, etc.) to place under the transmission valve body to catch all the drips, and move the drain pan out of the way. Now you will want to clean out the inside bottom of the oil pan. Use paper towels, carb cleaner, brake cleaner, etc., and clean off the magnet and put the magnet back in the pan.

Pro Tip: The factory installed transmission oil pan gasket is a high quality gasket and can be reused many, many times, so use it, and do not throw it away. You can throw the replacement gasket that comes with your filter away when you are finished.

Pro Tip: Before doing all this work, tray and get under your TrailBlazer and measure the depth of the oil pan. There are 2 different filters which can be used. One for a shallow depth pan, and one for a deeper depth pan. The shallow pan measures about 2 & 1/4 inches deep from the pan flange, and the deeper pan measures about 2 & 7/8 inches deep from the pan flange. Now, armed with this information you can purchase the correct transmission oil filter!

Pro Tip: Dexron III, the fluid specified for your transmission has been discontinued and is superseded by Dexron VI, which is backward compatible with all previous Dexron AT fluids. Dexron VI is a much better fluid than Dexron III.

You will also need to purchase at least 4 quarts of Dexron VI transmission fluid in order to replace the fluid that you drained from the transmission. If I were you, I would purchase 6 quarts of Dexron VI just to be safe.

Now if you are planning on keeping your TrailBlazer for quite awhile and are planning on changing the transmission fluid again, consider purchasing a Dorman transmission oil pan with drain plug, Part Number 265-811 (about $32.00 from rockauto.com). This way, the next time you want to drain the transmission fluid, you can just remove the drain plug from the pan. If you do go this route, you will need to use a transmission filter for the deep pan (such as Purolator P1267 filter).

OK, so now reinstall either the new Dorman pan, or the cleaned factory pan and tighten the transmission oil pan bolts to 13 foot-lbs. Take the TrailBlazer down off the jackstands, and add at least 3 quarts of the Dexron VI to the transmission through the dipstick tube. Now start the engine and check the transmission dipstick. Add Dexron VI until the fluid comes up to the cold mark on the dipstick. Now sit in the driver's seat, place the parking brake on and with your foot on the brake pedal, shift your transmission through all the gears and then back to park and recheck your fluid level.

That's all there is to do it.
Do you have the dorman pan ? Im thinking about getting one
 

·
Registered
2004 chevy trailblazer_lt
Joined
·
1,040 Posts
Diamond193 - yes, I do have the Dorman transmission oil pan. Well worth the money. I also put one on another of my vehicles that did not have a drain plug in the pan. Both Dorman pans were vary well made, and have made my life easier since I like to drain out some old ATF once a year and replace it with fresh. Keeps the additive package in the transmission fluid fresh.

Miketexas, you are generally correct. However, once in a while replacing a clogged filter will help some rough shifting issues.
 

·
Registered
2003 Chevy Trailblazer LT
Joined
·
264 Posts
Diamond193 - yes, I do have the Dorman transmission oil pan. Well worth the money. I also put one on another of my vehicles that did not have a drain plug in the pan. Both Dorman pans were vary well made, and have made my life easier since I like to drain out some old ATF once a year and replace it with fresh. Keeps the additive package in the transmission fluid fresh.

Miketexas, you are generally correct. However, once in a while replacing a clogged filter will help some rough shifting issues.
So with the dorman pan everytime you drain and refil you still replace the filter right ?
 

·
Registered
2006 chevy trailblazer_lt_ext
Joined
·
286 Posts
So with the dorman pan everytime you drain and refil you still replace the filter right ?
You would replace the fluid and filter every service interval. I do mine every 50k. If you tow or are a “spirited” driver I would suggest a more frequent interval. The 4L60E trans is the Achilles heal of these vehicles IMO.
 

·
Registered
2003 chevy trailblazer_ls
Joined
·
593 Posts
Diamond193 - yes, I do have the Dorman transmission oil pan. Well worth the money. I also put one on another of my vehicles that did not have a drain plug in the pan. Both Dorman pans were vary well made, and have made my life easier since I like to drain out some old ATF once a year and replace it with fresh. Keeps the additive package in the transmission fluid fresh.

Miketexas, you are generally correct. However, once in a while replacing a clogged filter will help some rough shifting issues.
I never seen a clogged filter do anything except cause the trans to fail eventually. If the trans filter is clogged it is clogged with failed transmission parts.
 

·
Registered
2003 Chevy Trailblazer LT
Joined
·
264 Posts
You would replace the fluid and filter every service interval. I do mine every 50k. If you tow or are a “spirited” driver I would suggest a more frequent interval. The 4L60E trans is the Achilles heal of these vehicles IMO.
Might just start changing it every year. I do tow but nothing crazy like most people do. I like to tow half of what im rated for.
 

·
Registered
2004 chevy trailblazer_lt
Joined
·
1,040 Posts
Diamond193 - with the Dorman pan. you do not have to change the filter every time you drain ATF from the pan. That's the great thing about having a transmission oil pan with a drain plug. As I indicated earlier, I normally drain 3 - 6 quarts (vehicle dependent) a year from my vehicles and replace with fresh. Then, every 3rd or 4th year I'll drain the pan, drop the pan,and change the filter. That way I am keeping the additive package "fresh" and not depleted. This way, the concentration of friction modifiers, antioxidants, etc., stays relatively constant in the transmission fluid.
 

·
Registered
2003 Chevy Trailblazer LT
Joined
·
264 Posts
Diamond193 - with the Dorman pan. you do not have to change the filter every time you drain ATF from the pan. That's the great thing about having a transmission oil pan with a drain plug. As I indicated earlier, I normally drain 3 - 6 quarts (vehicle dependent) a year from my vehicles and replace with fresh. Then, every 3rd or 4th year I'll drain the pan, drop the pan,and change the filter. That way I am keeping the additive package "fresh" and not depleted. This way, the concentration of friction modifiers, antioxidants, etc., stays relatively constant in the transmission fluid.
So i can get away with running the filter a few times between changes ?
 

·
Registered
2003 Chevy Trailblazer LT
Joined
·
264 Posts
Diamond193 - with the Dorman pan. you do not have to change the filter every time you drain ATF from the pan. That's the great thing about having a transmission oil pan with a drain plug. As I indicated earlier, I normally drain 3 - 6 quarts (vehicle dependent) a year from my vehicles and replace with fresh. Then, every 3rd or 4th year I'll drain the pan, drop the pan,and change the filter. That way I am keeping the additive package "fresh" and not depleted. This way, the concentration of friction modifiers, antioxidants, etc., stays relatively constant in the transmission fluid.
Ill look up the pan if anybody has a link to it please post. I do not shop on amazon so please elsewhere
 

·
Registered
2004 chevy trailblazer_lt
Joined
·
1,040 Posts

·
Registered
2004 chevy trailblazer_lt
Joined
·
1,040 Posts

·
Registered
2007 chevy trailblazer_ls
Joined
·
15 Posts
Do you have the dorman pan ? Im thinking about getting one
I have on '07 with a deep pan and I ordered a replacement pan with a drain plug, makes partial changes easy. Doing a DIY complete flush is actually easy, there are a number of videos on YouTube on how to do it. If you're mechanically inclined you might want to change the 1-2 accumulator while you have the pan off. The parts are cheap and will make 1-2 shifts much better.
 

·
Registered
Joined
·
2 Posts
I have an 03 trailblazer with the 4.2 vortec inline 6, idk much about transmissions but mine is just acting goofy. I have 238,801 on the odometer and I need to change the fluid in the tranny, just looking for tips when changing fluid and filter.
Our transmission went out at 230,000 miles. I had it rebuilt for $1600.00 and she's still going.
 
1 - 20 of 85 Posts
Top