Greetings all! I wanted to know if there was any way to drain ALL the fluid from the transmission, not just what's in the pan but all of it. It had started slipping so I: drained what was in the pan, changed the filter, and replaced about 5 quarts with ATF +3. This fixed the slipping, but I think I had put more fluid in than what came out (the fluid is on the correct mark on the dipstick now, it was probably low before). This vehicle is a fleet vehicle for an auto parts store, and it has served its purpose well with 267,000+ miles. The transmission has never been replaced! My boss didn't want to have it power flushed if he could help it since it is kinda pricey. I told him I would post this question on this group and see what I could come up with.
If it helps, it is a 3.3L engine, and I believe an A-604 tranny.
Disconnect tranny cooler return line, extend the end coming from the cooler with rubber tubing as necessary and place end of tubing into empty bucket. Start engine to allow the tranny's own pump to push old fluid into the bucket. Add fresh makeup fluid as necessary to keep the level within proper range as old fluid gets pumped out. Move shifter through the shift settings a couple of times during the process.
You will never get 100% of the old fluid out because it's a dilution process, but if you use about 50% more fluid than the total capacity as given in the shop manual (counting the 5 qts. that you already did with the filter change), you'll end up with well over 90% complete flush.
It's just as well not to do a high pressure flush. It is claimed by some that this could jarr lose deposits that might better be left where they are and create problems.
The above-described process is arguably the optimum combination of low cost, thoroughness, and least risk of creating new problems.
ATF+3 is the right fluid, so continue with that since you already started with it, although some dealers and informed individuals apparently would have used ATF+4, considered to be a better fluid (with
267k on the existing tranny, is anyone going to argue that ATF+3 is a problem?). (Before someone corrects me, the TSB on this - #21-006-01 - says to use ATF+4 on everything except '99 and earlier minivans due to wear-in issues in the torque converter clutches if ATF+4 is used. The logic apparently being used by many dealers, probably correctly, is that with a 5+ year-old minivan, wear-in is pretty much a done deal. Therefore the prevailing wisdom is ATF+4 for everything.)
Bill Putney (to reply by e-mail, replace the last letter of the alphabet in my address with "x")
I believe that you are correct that the TSB specifically exempted 1999 and older 4-speed minivan transmission from using ATF+4. That said, and supporting your statement about what dealers are actually using, I had my
1999 T&C trans fluid replaced at the dealer two years ago (then at 36K miles) and when I asked they said they used only ATF+4. The receipt also clearly stated that ATF+4 was used. I have not noticed any problems with the newer ATF+4 synthetic fluid.
I purchased the re-usable silicone/metal trans pan gasket and plan to do the next filter change myself shortly using ATF+4 again. If anyone knows any reason why ATF+4 would not be a good idea, I'd appreciate knowing since I could just as easily use the cheaper ATF+3 as well. Thanks.
Well, Bill, I'm finally going to argue about this one. I've seen this solution bandied about here and there for some time now, and as a recommendation to a newbie tech, I think it's really fraught with the possibility for disaster. My recommendation would be: a standard pan drop, filter change and refill ought to be good enough. If you're concerned about a mess when dropping the pan, pump as much of the old fluid out as possible through the dipstick tube.
I think my main concern with this flush idea is the possibility that the trans will pump itself dry. I realize that you make the point to 'add fresh makeup fluid' as necessary, but I know from experience in trying new things like this, that the process often becomes much more chaotic than originally planned. I don't know about yourself, but to me, the idea that the trans pump would run dry is a little scary. Perhaps my concern is needless? Or is there the chance that the pump will suck air for awhile, and cause all sorts of resulting bad secondary effects? Has anyone considered this? I'd like to know.
My second concern with this is that it wastes fluid! This ATF+4 stuff is expensive, and even though you might make the claim that the net cost is lower than replacing/rebuilding the transmission, I question how much more effective this method is than just dropping the pan and replacing what fluid comes out at regular intervals. Pissing away expensive fluid for a maintenance process seems like overkill to me, not to mention a waste of resources. Certainly there will be some older fluid still in the transmission if you forego the flush, but if you're maintaining a regular maintenance interval, how much does it really matter? I think little. If there's a study that indicates that the benefits of throwing away good fluid in a flush are really high, I'd like to see it.
Thirdly, I think that this is a potentially dangerous process. Engaging a vehicle's transmission with the engine running while it's being worked on is inherently dangerous. Not to mention that typically it will be supported on jack stands during the process; I'm always particularly concerned about entering a vehicle that's supported on jack stands, as would be necessary to operate the shift lever. It seems to me that you're creating an additional opportunity to knock the thing off the stands; perhaps not a real easy thing to do, but to be honest, claustrophobic as I sometimes get when lying under a vehicle, I don't like taking chances.
So I'm interested in seeing a debate on this topic. I'll freely admit that I'm going to be tough to convince that this flush idea is a good one, but I'll try to keep an open mind. Whatcha got?
I can't back up anything that I said with anything other than gut feel and a little (more than none, less than a lot) experience in doing the procedure I described.
You are right - for me, it did initially become more chaotic than I had anticipated. However, within less than a minute of starting it, my over-optimism became obvious, and I stopped and had my wife come out to assist. She sat in the driver's seat to periodically start the engine, move the shifter, stop the engine, etc. at my command. With a helper it was very manageable. It will be easy going the next time I do it. I even spliced the line for easy disconnect and re-connect for future flushes.
Once I got my bearings, it was very simple to periodically check the fluid - it wasn't like it was going to empty iteslf out in a minute or less - there was a comforable amount of time to check fluid during the process, and when it started getting low, stop the engine and add more fluid, then proceed. Never came close to sucking air.
Re: the wasted fluid, my reasoning is this: If one believes that the fluid deteriorates at a certain rate (due to temperature and shearing), then over the life of the vehicle, one would need to put (approximately) the same amount of fresh fluid thru the vehicle whether in a partial-change fashion, or thru sudden 100% changes - the former being closer to your one pan-full at a time, the latter being closer to my
90+% transfusion at a time. Since any time any procedure is done, there is a certain fixed amount of overhead involved (in getting tools, out, cleaning up, etc.), I figure I will do my 90+% procedure less often than you would have to do your less-than-50% change to get the same benefits (in tranny life and performance), and due to the "overhead effect", will save time overall. But yes - I probably do waste more fluid. But for less total money than if I paid a shop to do it, I get a *lot* more fluid to do with what I want, and get the benefit of a more thorough change.
As far as the danger, I would not be under the vehicle during any of this - I make the rubber hose long enough to do it all standing up (except for the initial hookup).
That's it for me. We each look at the facts at hand and make our decisions, and get the results good or bad. I am not saying your philosophy is wrong. I'm just saying what feels right for me as one who is arguably an obsessive-compulsive (as in "Hmmm - in the above post, did I spell "shearing" right? Is it "procede" and "preceed", or is it "proceed" and "precede", but I know it's "procedure"), but getting less so as I get older.
Bill Putney (to reply by e-mail, replace the last letter of the alphabet in my address with "x")
Thanks Bill for your quick reply! I have heard of this procedure before, but couldn't remember the exact steps to be performed; so thank you for clearing them up for me :)
I will let my boss know and see what he wants to do. So far he is keeping the van in town for a couple days to see how the tranny is acting before he "re-assigns" it to "out of town duty." He may want me to do it on a saturday, which is our oil change day for the vehicles.
I will post back if I perform this procedure. Thanks again!
This is the initial feeling I got when I read this procedure. After thinking it over I will perform this on the van if I can get a helper. I would rather not do it alone. I don't think he will want to put ATF +4 in it, but just keep the +3 stuff since we carry that in our store.
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