To change transmission fluid or not?
04-21-2007, 08:30 AM
#11
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I am agreeing with the 2 previous posts, to many times we flush a trans out at work and 2 weeks later BOOM, its done.... time to get it rebuilt... I would drive yours and beat the crap out of it until it pukes 
04-21-2007, 09:01 AM
#12
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This is from Butch on Denalitrucks.com
1) If you have over 10000 miles since the filter was last changed, drop the pan, clean it
completly, change the filter and bolt back up with a new gasket. (If you jump ahead and get the fitting in and pump out the first 3-4 qts before you drop the pan it will be empty and much cleaner to do the filter change) If you have less
than 10000 you can skip ahead to #3, although its always safer to change the filter
and clean and check the pan for particles or clutch pieces (not a good sign!)
2) Add 3 or 4 qts new fluid to bring it to the full mark on dipstick.
(DON'T START IT)
3) Remove the upper transmission line from the radiator, only very little fluid will drip,
if any at all, because its higher than the transmission.
4) Screw a short fitting into the radiator that you can attach a piece of tubing to. It is and odball fitting size on our newer trucks, and some just stick the tubing in the hole and hold it, a little messier but it works. You will need about 2 or 3 feet of 3/8 clear plastic
tubing. Clear gas line works great, but you can use almost any plastic or vinyl
tubing.
5) Clamp the tubing onto the fitting you put in the radiator and run the tubing over the
radiator support and out the front of the truck and into a gallon or larger jug.
I tape a big nut as a weight on the end of the tube to keep it in the jug, if you have a
helper they can just hold it in.
6) Start the truck. Fluid will start pumping out the tube into the jug. Watch the tube
untill you see bubbles or hear a bubbling sound and immediatly shut the truck off. It
will take about 30 seconds and will pump out 3-4 quarts of fluid.
7) Add 3-4 quarts of new fluid, to the full line on the dipstick, empty the jug (don't
forget that) and start it up again as before and watch for bubbles, and shut it off
again.
8) Repeat again, adding 3-4 quarts, empty the jug, start, watch for bubbles and shut
off.. If you really want to be assured that you have 100% change, add just 2 more
quarts and repeat. If the fluid was dirty, or the new fluid is a different color, you will
see the color change in the clear tube, this is when you know you have changed all
the fluid. I usually watch for the fluid color change rather than the exact number of
quarts.
9) Remove hose, replace fitting with transmissiom line, fill transmission to full line,
start the truck and warm up, when hot check and fill to line on dipstick.
You've just changed and flushed every drop of old fluid from the transmission, converter and cooler system. If your changing to synthetic, you will be 100% synthetic, none of the oil will intermix with this flushing procedure because the fluid follows one path from the filter to the pump, through all the transmission passages, through the converter and then out the cooler line and back to the pan. As my Denali only has 7000 miles on it I haven't changed it yet, but in my last truck, a 2000 Sierra 5.3, it took 14 quarts as i remember to flush it. Be safe and get 15 quarts. This is not a back-flush and will not dislodge any particles in the tranny. It is completly safe and easy to do. It may sound difficult but once you get the fitting made, you can do a complete flush in less than an hour for only the cost of the fluid.
1) If you have over 10000 miles since the filter was last changed, drop the pan, clean it
completly, change the filter and bolt back up with a new gasket. (If you jump ahead and get the fitting in and pump out the first 3-4 qts before you drop the pan it will be empty and much cleaner to do the filter change) If you have less
than 10000 you can skip ahead to #3, although its always safer to change the filter
and clean and check the pan for particles or clutch pieces (not a good sign!)
2) Add 3 or 4 qts new fluid to bring it to the full mark on dipstick.
(DON'T START IT)
3) Remove the upper transmission line from the radiator, only very little fluid will drip,
if any at all, because its higher than the transmission.
4) Screw a short fitting into the radiator that you can attach a piece of tubing to. It is and odball fitting size on our newer trucks, and some just stick the tubing in the hole and hold it, a little messier but it works. You will need about 2 or 3 feet of 3/8 clear plastic
tubing. Clear gas line works great, but you can use almost any plastic or vinyl
tubing.
5) Clamp the tubing onto the fitting you put in the radiator and run the tubing over the
radiator support and out the front of the truck and into a gallon or larger jug.
I tape a big nut as a weight on the end of the tube to keep it in the jug, if you have a
helper they can just hold it in.
6) Start the truck. Fluid will start pumping out the tube into the jug. Watch the tube
untill you see bubbles or hear a bubbling sound and immediatly shut the truck off. It
will take about 30 seconds and will pump out 3-4 quarts of fluid.
7) Add 3-4 quarts of new fluid, to the full line on the dipstick, empty the jug (don't
forget that) and start it up again as before and watch for bubbles, and shut it off
again.
8) Repeat again, adding 3-4 quarts, empty the jug, start, watch for bubbles and shut
off.. If you really want to be assured that you have 100% change, add just 2 more
quarts and repeat. If the fluid was dirty, or the new fluid is a different color, you will
see the color change in the clear tube, this is when you know you have changed all
the fluid. I usually watch for the fluid color change rather than the exact number of
quarts.
9) Remove hose, replace fitting with transmissiom line, fill transmission to full line,
start the truck and warm up, when hot check and fill to line on dipstick.
You've just changed and flushed every drop of old fluid from the transmission, converter and cooler system. If your changing to synthetic, you will be 100% synthetic, none of the oil will intermix with this flushing procedure because the fluid follows one path from the filter to the pump, through all the transmission passages, through the converter and then out the cooler line and back to the pan. As my Denali only has 7000 miles on it I haven't changed it yet, but in my last truck, a 2000 Sierra 5.3, it took 14 quarts as i remember to flush it. Be safe and get 15 quarts. This is not a back-flush and will not dislodge any particles in the tranny. It is completly safe and easy to do. It may sound difficult but once you get the fitting made, you can do a complete flush in less than an hour for only the cost of the fluid.
04-21-2007, 09:52 AM
#14
hmm...I can see exactly where you are comming from, and I was aware of the bonding between parts.....Try to find a service history really...But if u belive its NEVER been done..then dont do it...
ITs actualyl funny..my dads buddys tranny jsut went in hsi van last night at our place...2 weeks ago it was flushed.
Listen to these other guys....unless you cna find out the last tiem it was done
ITs actualyl funny..my dads buddys tranny jsut went in hsi van last night at our place...2 weeks ago it was flushed.
Listen to these other guys....unless you cna find out the last tiem it was done
04-21-2007, 01:50 PM
#18
Originally Posted by UnrthdxDream
hmmmm what if im sitting at about 36k miles and dont know if its been flushed since i bought it used at 29k? 
As mentioned above, if you're going on 100k with the original fluid, I wouldn't do a complete flush as it may be the death of that trans...the junk and varnish that has built up is actually filling clearances and holding the trans together lol (this was especially the case with older Ford autos IIRC)
04-21-2007, 02:42 PM
#19
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Just want to add, use the Dexron VI oil, its great stuff.
Look at
http://www.petro-canada.ca/pdfs/IM_8017_E_v14.pdf
this is the same oil carried by you local GM dealer.
//
Look at
http://www.petro-canada.ca/pdfs/IM_8017_E_v14.pdf
this is the same oil carried by you local GM dealer.
//
