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I'm looking to do a transmission fluid flush and change the conventional oil with synthetic. In efforts trying to find the best way to do the flush, a question arose. What is the path of the oil in the tranny? Specifically, from the pan/reservoir, where does the oil go once it is picked up from there?
My hope is that the oil from the pan gets routed from a to z through the tranny. I found a diagram a while back showing some of the fluid path, but I can't find it anymore.
Due to the age of the behicle the shops that have the correct machi es are telling me they wont do it. Lol. This one time im not being too cheap. Some places want $300! Crazy.
Yeah, we didn't recommend trans fluid change if it had over 100k miles either. If the customer wanted it done anyway, it was no guarantee it would go into gear with new fluid. There were a couple that did that, we warned them it could happen.
Yeap. I understand the risks, but i feel a little better about it since my tranny was rebuilt 12k miles ago and i already changed the oil once. The rebuild shop has since gone bust so no warranty.
As you probably know, simply draining the fluid won't help, as more than half of the fluid is still retained in the torque converter. You might be able to take it out of the cooler lines with the transmission somehow turning, but that sounds like an awful lot of work.
Scope, it is going to be a lot of work! Im hoping that the return line to the transmission will have some suction. Here is my plan (if no suction, which is most likely case) after some more thinking. Two person job, min.
1. Drop pan, inspect and clean magnets. Assuming no unexpected metal chips, change filter reinstall pan. Fill with cheap synthetic atf.
2. Disconnect feeder line to oil cooler. Place end in big bucket. Bucket should have markings for 1 quart intervals.
3. Disconnect return line. Connect return line to bottom of a fresh atf reservoir that can be raised or lowered to add just a few inches of head than the level of the fluid in the reservoir pan. This must be lowered when vehicle is off so no overfill of fluid In tranny. Fill one quart of fluid into reservoir at a time as the used fluid bucket fills one quart.
3.5. As you are doing step 3, cycle through 4x4 modes and gears... (is this ok to do? The idea is to move the oil in the transfer case as well).
4. When 12 quarts of fluid fill in bucket. Stop. Dump used fluid from bucket. Repeat step 3 with mobil 1 synthetic atf.
5. test drive car nervously hoping everyone who advised not to change fluid was wrong!
6. if step 5 is a success, test drive next day morning. See if transmission behaves properly. Hopefully it changes out of 3rd to OD without initial delay.
Is there a drain plug on Toyota torque converters? I'm sure the cooler line won't have suction, you need a pump (trans flush machine) to do it that way. I guess you could add fluid to the fill tube while the cooler line is off, but it'll be tricky. Or, just do several drain & fills a couple miles between.
bswarm, I also thought of the drain and fill idea, but that gets very expensive and still at the end you merely have a more diluted mix of conventional oil to synthetic. I purchased a little fluid pump (manual) in the case that my above plan doesn't work, but I don't feel comfortable 'forcing' fluid through the system. I think having it pump the fluid through as if there was no difference to it's regular operation, and just intercept the outgoing oil and supply a new feed to the return is safer for the transmission.
It should be noted that when i changed my transmission fluid about 5k miles ago 9about 7k after rebuild) I did so because the tranny temp reached over 300 and research showed that the oil becomes useless after that. The pan had a lot of residue and sludge for only 7k of use on that oil, and for a rebuilt tranny.
It's been a long time since I've used a trans flush machine (retired) but I think they run about 30psi. The flush machine automatically adjusted the pressure and direction of flow. Have power steering? MacGyver method?
The trans cooler line pressure is not the same as the trans pump line pressure. Yes I was talking about p/s inline with trans cooler line, but that was a MacGyver joke. It'd be too much pressure.
Yeah, I was thinking that the pressure from the PS pump would be too much.
My hand crank fluid pump should be enough if I have to pump the fluid... which would be in the case my plan above fails. If all the oil is delivered by sat morning, I'll be doing this saturday
As to the drain and fill, I decided to do that to my wife's Suburban. Looked into it as you are and didn't have the time then. GM recommended synthetic for shifting problems. I was hesitant like you because of the cost. I did it that way and got immediate results, with better shifting. The first time I changed the filter, and at the oil changes after that I would just drain the tranny, it has a drain plug. And fill with the synthetic. It has really helped "calm" that tranny down, no more hunting. I'm not saying it will work great with this Toyota tranny, just more food for thought.
Interesting, thanks for the info. Depending on the year of the suburban, the ATF Toyota reccommends, dexron, is a gm spec... so there is some similarity.
I'm not sure that will work as well as you hope. I believe the transmission has pressure regulators, that divide the fluid between the transmission and torque converter. (At least this guy so believes.) If you can't supply enough pressure to "open" the regulators, I'm not sure where the fluid would go with just hand-pumping.
Also, without an integral drain plug (on the "bottom"), I'm pretty sure the torque converter needs to be rotating, or you will only remove the fluid from one side.
I suspect that commercial "power flush" equipment pressurizes the fluid to where it "should" open the regulators. But I have no idea how that helps with a non-rotating torque converter.
As sketchy as it sounds, if I felt that I needed to remove "most" of the fluid (and I'm not certain that you do), I would be inclined to have the engine running and use the transmission's own pump to pump the fluid out through the cooler lines.
Let us know how it goes (and don't be afraid to use a camera).
Well, i'll do my best with a camera. Now, I need to convince my friend a lunch and some beers is worth the 'fun' to help out with this
Scope, I feel I need to get all of the fluid out because I read that the conventional and synthetic fluids don't mix well in a transmission. Also, if I do the work now, I won't have to change oil often in order to dilute the atf with mostly synthetic. This should cost less in the long run.
The trans flush machine I used was done with the engine running, so that included running through the torque converter, it did a really good job. And Redline Synthetic ATF does mix with regular ATF, that's premium fluid. I use it in my Saturns, it improved the shift quality.
The trans flush machine I used was done with the engine running, so that included running through the torque converter, it did a really good job. And Redline Synthetic ATF does mix with regular ATF, that's premium fluid. I use it in my Saturns, it improved the shift quality.
OH, does it really mix.. It is premium fluid, and the price isn't any less than premium either. lol. But, perhaps it would have been worth it? I don't know, the benefits of a full flush still appeal to me.
Again, i would love to pay someone $200 to do all this but noone around is willing to take the risk. I offered not to hold them responsible, etc, but... nope.
Well guys, a definite success yesterday. We ran into a couple of small issues, but otherwise it's really pretty easy.
I ended up ditching the hand crank fluid pump idea and instead used this relatively high volume, low pressure hand pump from harbor freight. If you ever use this, make sure you have 3/8" oil hose because the orange hoses it comes with is a complete joke! The suction end can't even hold it's cross section under suction, it just collapses.. lol. stupid! http://www.harborfreight.com/multi-u...ump-66418.html
1. Drained oil from tranny and transfer case from drain plugs. I used a clear plastic storage box to mark the 1 quart increments. I poured 1 quart of water in there incrementally and made the marks, no guesswork!
2. I removed the oil pan and inspected the interior. Everything looked perfectly clean, after all the oil was changed about 5k miles ago.
2.5 Put the cheap synthetic fluid in, removed 6 quarts, put 6 quarts.
3. Remove skid plate, undue proper hoses and connect a 1-foot section of hose to the feeding pipe (oil comes out of this one) and a 4-foot section to the return.
Then my friend and I promptly got into a little argument about the return line characteristics. lol. His experience with his aisin tranny on his cherokee was such that there is a LOT of pressure in the coolant hose line system, and a lot of suction pressure. I said, I don't think that is the case here and so we decided to see if my original idea of a 'reservoir' or fluid held up high to add some head to the system would be enough to go through the tranny. So, we did this.
Yeah, definitely no suction in that line, at all. (I had moved away from my original reservoir+head idea after some more research, which is why i preemptively purchased the hand pump... also, i moved away from the hand crank one because I was not sure what pressure it will be feeding with and I felt I wouldn't have good control over the flow of the fluid)
4. Run the oil through. So, it was tough keeping up with pictures on this since both of us had to be on top of our work, but I managed some pictures and one video.
Here is the 3rd time we are filling the container with oil. The first two times (both 6 quarts each) would have completely flushed the conventional fluid out and now we are getting just the new cheap synthetic fluid. By the end of the 3rd container we would have removed 6 quarts of the remaining conventional oil, added 12 quarts of the cheap synthetic, and during the 3rd container filling we were already adding the mobil one synthetic.
So, at this point all there was left to do was to add the 12 quarts of mobile one. We had the rythm down so I was able to stay away from the car's kill switch and take some pics. Here is how we did the pumping, simply look at the container and once it has reached 1 quart, my friend would make sure that he has pumped 1 quart back into the system.
Ignore that orange hose.
And here is a video of the process. Que the anti-dramatic audio layover!
RESULTS: There was a scare at first, followed by a lot of confusion. I kept perfect records of the oil comping out and going in. I did have a big spill at one point so I estimated a total of about 1 quart loss to spilling (overkill). But, after the fluid was in and things plugged back in, turned on the car and moved the shift lever to R, didn't get the familiar slight jerk. Let it roll down the drivewat to level ground, and sure enough, there was nearly no pull in the tranny. Checked the oil level and the oil didn't even show up on the dipstick. TOTALLY confused we put in one quart and the car started acting normal, but still the dipstick was barely tipping the oil. Put in a 2nd quart and went for a test drive to get it up to temp. Checked the fluid level and it was OK. SO, assuming one quart went to spills, how was I one quart short???? I kept a record of the fluid exchange and everything was adding up... Totally confusing.
ANyway, the rest of the evening it drove perfectly and without issue.
I forgot to mention that I bypassed the B&M oil cooler that I had spent so much time on installing. I don't think it's doing anything. The other one I installed in the front of the car seems to be doing all the work anyway. We shall see.
I am about to go for a test drive this morning. One of the issues before was that the transmission didn't kick out of 3rd and into 4th during the first drive of the day. It would linger for about a mile or so before it changed out properly and then the rest of the day would be no issue. I don't think the atf change would have effected this, but i'll see soon.
03-04-2015, 02:50 PM
