84CUCV
3/4 ton status
I have a 700, 400 and a 4l80e that need it. not looking to do a drop and fill. looking to get it all out and put all new atf in. so how is it done? thanks
CK5
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How to flush a tranny
- Thread starter 84CUCV
- Start date
YZEATER
1/2 ton status
i'm pretty sure you can disconnect the tranny cooler lines, put one line into a bucket with new fluid, and the other in an empty bucket and run the engine till the fluid comes out clean.
I don't think it's possible to do it yourself, correctly.
The fluid lines are pressurized. Disconnect them from the cooler, the fluid coming out is under pressure, the return line isn't, thus the fluid isn't going to return at the rate it's leaving.
The trans flush offered at places forces fluid in while the old is removed, and uses a LOT of fluid IIRC. Even 15 quarts at $2/bottle (both probably low numbers for a flush) gets you to $30, while professional flush runs what, $75?
The fluid lines are pressurized. Disconnect them from the cooler, the fluid coming out is under pressure, the return line isn't, thus the fluid isn't going to return at the rate it's leaving.
The trans flush offered at places forces fluid in while the old is removed, and uses a LOT of fluid IIRC. Even 15 quarts at $2/bottle (both probably low numbers for a flush) gets you to $30, while professional flush runs what, $75?
5280k5
1/2 ton status
The flush machine utilizes an electric pump to feed new fluid in at a 1:1 exchange rate for old fluid coming out. The machine I've used runs a minimum of 12 qts of fluid through and had a max capacity of 22 qts(for really dirty fluid this was great). The dealership is used to work at got a lot more than $75 for the service but it did include a trans. cleaner before and
conditioner additive afterwards, yeah I know big deal.
Either way, it's still a much cheaper alternative to replacing a tranny from lack of maintnenace. Ask me how I know that.........
conditioner additive afterwards, yeah I know big deal.
Either way, it's still a much cheaper alternative to replacing a tranny from lack of maintnenace. Ask me how I know that.........
84CUCV
3/4 ton status
ok i will get a few prices i guess. was hopeing to do it myself.
I don't understand what you mean by "correctly". I just measure how much is coming out and put that much new in the fill tube. The gallon jugs usually have a handly little scale on the side. Yes, the machine with the giant piston is handy, but in the end if you have the right amount of fluid in, what's the difference?
I can't see paying $60+ for something this simple.
I can't see paying $60+ for something this simple.
84CUCV
3/4 ton status
i guess my next question would be. what is you mess up and its to little atf? do you hurt the trany?
Pookster
1/2 ton status
Nothing really beats a tranny flushing machine- its one of the few maintaince things that the machine really is better.
THe question is, is the fluid they are replacing as high quality as the one your putting in?
If your tranny was neglected, go get a flush. At least you can start fresh from there.
If your tranny was under constant fluid changing (like every year or two) you probably dont need a flush.
A flush is also very good if you get water in your tranny.
THe question is, is the fluid they are replacing as high quality as the one your putting in?
If your tranny was neglected, go get a flush. At least you can start fresh from there.
If your tranny was under constant fluid changing (like every year or two) you probably dont need a flush.
A flush is also very good if you get water in your tranny.
I've done it myself with a mechanic friend. We did it on my '99 Ram a few years ago.
I bought a 5 gallon (yep, 5 gallon) bucket of Valvoline ATF+4 (damn MOPAR) and we sunk the return line into that. Started the truck and it pumped out of there and into an empty bucket we had.
Worked pretty good but we ended up needing still another few quarts of ATF to top it off correctly. However MOPAR automatics aren't known for their small size so it might require less with a GM automatic.
I just do a pan drop myself now. That truck had an unknown history and a so-so quality tranny from the factory so I decided to do the whole flush routine first.
If you drop the pan and take off the filter and then let the thing sit and drain overnight a suprisingly large amount of fluid comes out. I did this with my Tracker and thought for sure it was leaking into the transfer case because I had to add so much. Turned out I had just drained off 75% of the capacity while it sat overnight.
I bought a 5 gallon (yep, 5 gallon) bucket of Valvoline ATF+4 (damn MOPAR) and we sunk the return line into that. Started the truck and it pumped out of there and into an empty bucket we had.
Worked pretty good but we ended up needing still another few quarts of ATF to top it off correctly. However MOPAR automatics aren't known for their small size so it might require less with a GM automatic.
I just do a pan drop myself now. That truck had an unknown history and a so-so quality tranny from the factory so I decided to do the whole flush routine first.
If you drop the pan and take off the filter and then let the thing sit and drain overnight a suprisingly large amount of fluid comes out. I did this with my Tracker and thought for sure it was leaking into the transfer case because I had to add so much. Turned out I had just drained off 75% of the capacity while it sat overnight.
Drop 2 quarts of oil out of your engine. Pour two in. You've contaminated the 2 quarts that you just put in. Doesn't really serve a point does it?Blue85 said:
Either you mix as much fluid as possible to minimize contaminants, (expensive) or you prevent good fluid from mixing with bad as much as possible. Not sure this is entirely what the machines do, but if they are removing all fluid pumped out and returning new fluid in the return line, then the fluid is likely not "mixing" much. I'm sure there is some contamination, but not like pouring 2 new quarts of ATF into a tranny pan with 2 quarts of old fluid, and internals holding another 11 quarts of old fluid.
Thunder
3/4 ton status
Blue85 said:
How true! I have flushed many trannys this way and never had a problem. Very Easy to do. Its not rocket science. All you need is a bucket, a wrench and some tranny fluid. drop the pan do a basic fluid filter change, then pull the cooling line at the radiator. start up and run a couple of quarts out. add a couple of quarts. Keep adding and flushing till it comes out nice and pink and clean. flush out a couple of quarts add a couple of quarts its a real No brainer.
Jees.... if you are worried abouit a tiny little bit fluid contamination. Just pull the tranny and rebuild it. With white gloves on.
dyeager535 said:
This may be true, but the machine can't do any better. The tranny pump picks up fluid from the pan through the filter, so whether new fluid comes from the fill tube or the return line, it will still mix in the pan. This is why they sometimes flush more fluid through than the total capacity of the tranny.
Plus, in your analogy above, the result is still cleaner than where you started. If you really want to be throrough, pull the pan and let it drain overnight. Then fill the pan back up and start the flush.
If you remove a cooling line, start the engine, turn it off, fill what was removed, and repeat until you've done 15 quarts or so, you've probably done what the machines can do.
However, anyone that has gotten water in their automatic will surely attest that you will spend TONS of money on automatic trans fluid trying to get the color back to what it should be. No idea if the machines are more efficient, or they simply use a lot of fluid, but I've BTDT and probably used twice as much fluid as the trans called for, and STILL had pink fluid.
I have never seen a GM transmission dipstick tube that will allow you to dump nearly as much fluid in as it forces out throught the tranny line. (at least unpressurized) The fluid transfer is much faster through the lines than you could ever accomplish with a funnel. I would not attempt to try and keep up the fluid level with a line disconnected for fear of running the transmission dry.
However, anyone that has gotten water in their automatic will surely attest that you will spend TONS of money on automatic trans fluid trying to get the color back to what it should be. No idea if the machines are more efficient, or they simply use a lot of fluid, but I've BTDT and probably used twice as much fluid as the trans called for, and STILL had pink fluid.
I have never seen a GM transmission dipstick tube that will allow you to dump nearly as much fluid in as it forces out throught the tranny line. (at least unpressurized) The fluid transfer is much faster through the lines than you could ever accomplish with a funnel. I would not attempt to try and keep up the fluid level with a line disconnected for fear of running the transmission dry.
84CUCV
3/4 ton status
OK thanks for the help guys.
84CUCV
3/4 ton status
really, i was thinking if it was dry for a short time it would not matter. shows how much i dont know
