Changing the ATF

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I would like to change the fluid as it has never been changed in 9 or so years. The shop I went to wants 110 to hook it up and exchange fluids. They said if I want the pan dropped and new filter it would be double, so about $220. Thats a bit steep, so I would like to do it myself.

My question is, can you drain all the fluid by disconnecting the trans cooler lines and dropping the pan? Apparently just dropping the pan will only yield about 4 quarts or so. I rather do it once and throughly, and change out all fluid and the filter.
Also, is it safe to reuse the old gasket, or should I put the new one that came w/ the generic trans filter I got at Kragen Auto?
Any advice is appreciated
BTW it is a 99 monte carlo, 3.8L
 
You can do a "flush" via the cooler line by yourself. I dont have the instructions at the moment but they can be had on Amsoils site. Do not reuse the old tranny pan gasket. You will usually get one with a new filter. You will need around 15 quarts of whatever brand ATF you prefer. I always buy a few extra just in case. Also lubegard is also something to consider in a vehicle with higher mileage. A cooler line flush will get pretty much all of the old fluid out if done properly. One more recommendation would be to add a Magnefine in-line filter. The stock filtration on these trannies is quite poor. Good luck!
 
The car is old but only has some 30k miles on it. I want to change the fluids b/c of the extended time they have been in the car, not b/c of miles. That in line trans filter looks neat but I doubt I need it. Also, the mechanic said that changing the filter isn't usually necessary b/c they rarely are clogged/have filings in them anyways, not sure about that though.
 
With on 30K on the vehicle, you should be fine with changing it via the cooler line flush method. I would not think you need to drop the pan and change the filter. Doing it via the cooler line flush method should be slightly better than a shop doing it as there should be less mixing of old and new fluid since you typically dump out 2 QTs of old, thes stop engine and add 2 QTs of new.

The Magnefine filter is a great idea for any AT and costs about $15-20. A great inventment. Its especially important if one wants to use synthetic ATF and will keep the ATF in the AT for say 50K miles. Since in that case the wear metals will build up for 50K rather than being dumped earlier.
 
For those interested, here's the fluid change method I use on all my cars that don't have a torque converter drain:

1. Pull the transmission dipstick. Fresh fluid is translucent and cherry red. Some darkening is normal, but if it is reddish brown or mustard color and smells like burnt varnish, it is worn out.

2. Make sure the fluid is warm.

3. Remove all pan bolts except for the corners. Remove the bolt from the lowest corner, then loosen the other corner bolts a turn or two. Carefully pry the pan to break the gasket seal at the lowest corner. Drain mostly from this corner. With good technique you can avoid or at least minimize the red bath.

4. Remove pan. Inspect the pan before cleaning. A small amount of fine grey clutch dust is normal. However, if you find metal shavings, there has been transmission damage. Remove all old gasket material. Some rubber gaskets are reusable. Clean the pan and magnet with solvent and wipe dry so there is no harmful residue. Shop air can be used to clean the magnet. Hammer back any pan damage from previous overtightening.

5. (Optional) Drill hole in pan at low point and install a drain kit available from most auto supply houses. Make sure the kit protruding inside the pan doesn't interfere with anything on the transmission.

6. Replace filter.

7. Position gasket on pan. Some gaskets have four holes slightly smaller than the rest to allow four bolts through the pan and through these smaller holes to hold the four bolts and gasket in place.

8. Hand tighten pan bolts in a criss-cross pattern. After that, use a torque wrench to tighten bolts to proper ft-lbs as per manufacturer.

9. Refill the transmission using only the amount shown as “refill capacity” in the owners manual (or an equal amount that was drained), using the type of fluid specified for the vehicle.

10. You now have replaced the trans fluid and filter according to manufacturer’s requirements. Fluid is changed in the pan only.

You can stop here and go to Step 17 if you just wanted a regular drop-the-pan fluid change. For a complete exchange of the fluid (including transmission body and torque converter) continue with the next steps.

11. Obtain the total system capacity of the vehicle from the manufacturer. Have this amount - plus a bit more - of fluid readily available.

12. Disconnect the oil cooler line from the oil cooler. Tickle the ignition to find the flow direction. Direct the stream of fluid toward a receptacle. It is better to use a clear length of hose with a shoplight laying next to it so you can see when all the old fluid has left the system.

13. Start the engine, let it idle to pump out old trans fluid until you start seeing air bubbles. This is a good time to shift through the gears to flush those fluid circuits.

14. Stop the engine. Refill transmission through fill tube with fresh fluid - same amount as pumped out (usually about 2-3 quarts).

15. When either the fluid color brightens or the total capacity has been replaced, shut the engine off and re-attach the oil cooler line. All trans fluid has now been changed.

16. Button everything back up. Clean up the mess.

17. Recheck the fluid level. With the car on level ground, set the parking brake and the transmission in Park or Neutral. Let the engine idle for a few minutes. Shift the transmission through all detents, pausing momentarily at each position, before returning the lever to Park or Neutral. Check the fluid level again and check for leaks. Refill fluid so it is slightly undercharged. This way it can be properly checked and topped off after a long drive.
 
If you would prefer not to change the filter then leave the old one in. Me, I would change it out just so I can inspect the pan and see whats going on. Your choice, but yes a bit premature at 30K. Notice the word your mechanic used was "usually". I have done this several times using Red Line ATF and Magnefine and am very pleased with the results.
 
12. Disconnect the oil cooler line from the oil cooler. Tickle the ignition to find the flow direction. Direct the stream of fluid toward a receptacle.

Looks like a good guide, thanks. What do you mean by tickle the ignition? Also, do you add fluid to the trans before disconnecting the cooler line? If so, wouldn't it just come out the line? Lastly, you say to turn the car on and put it through the gears, will it not hurt the trans b/c you are not hitting the gas while in gear, thus the gears are not moving?
Thanks
 
There seem to be three schools of cooler line flushes:
1) Follow the Amsoil directions, but I believe people have trouble refilling via dipstick as same rate its being pumped out.
2) Pump out 2 QTs of ATF, turn engine off and fill with 2 QTs, cycle until done (change in color or you have gone through enough QTs).
3) Pump out until you see air bubbles in the fluid line, then shut off engine and add what was pumped out. This method should have the least mixing of old and new fluids and in theory use the least new ATF and have the least mixing of old and new fluid.
 
Originally Posted By: monte

12. Disconnect the oil cooler line from the oil cooler. Tickle the ignition to find the flow direction. Direct the stream of fluid toward a receptacle.

Looks like a good guide, thanks. What do you mean by tickle the ignition? Also, do you add fluid to the trans before disconnecting the cooler line? If so, wouldn't it just come out the line? Lastly, you say to turn the car on and put it through the gears, will it not hurt the trans b/c you are not hitting the gas while in gear, thus the gears are not moving?
Thanks


He means to hit the starter for just a second. Long enough to turn the engine a little, but not long enough to actually start the engine running.

When the car is in gear, but not moving, no gears are turning. The only thing turning is the input shaft into the torque converter. I'm not sure how its bearings are lubricated, but I'd guess that just idling won't cause them to overheat. They might even be permanently lubricated like some wheel bearings, and then it's not a problem at all.
 
That car should have the 4T65-E auto trans. The gears in that transmission share ATF with the rest of the tranny for lubrication.
 
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