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Symptoms gone after fluid change, would the following help prolong life?


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AvantGuy
Novice
AvantGuy profile image

May 21, 2021, 3:11 PM

Post #1 of 10 (366 views)
Symptoms gone after fluid change, would the following help prolong life? Sign In

Hello, thanks! New member here.
My issue has to be among the most common, but I searched the forum and found some but not all answers.

Background
2oo1 Toyota RAV4 2.0L AWD 170K-miles
  • Trans fluid changed at 90K miles and again today, 170K miles.
  • Over 21 years and high mileage, never any trans leaks.
  • Trans oil level always at top, never had to add a drop.
  • Today: No check-engine light, no codes.

My question(s):
(I have trans slippage symptoms over last two days. Got trans fluid changed. Symptoms gone after the change (yet I understand up to 30% of old fluid can remain)
  1. If it continues to run well, would I be helping to prolong the life of the trans by getting a full flush right away (...if there even is such a thing) ?
  2. Is that not worth the risk due to potential particle dislodgement?
  3. If advised against powered flush, would it help to do a repeat fluid change to further decrease the percentage of old fluid?
  4. Is there a 3rd trans fluid procedure, neither full flush nor "manual" fluid change, but something in between that I should consider such as, as I understand it, dropping the pan to change the filter, gaskets, and other stuff under there? (no leaks, ever)
  5. Re #4, because it has never leaked, should I not do a gasket replace? Is it wrong to leave the old filter? As far as I know, the filter is the original -- the pan has never been dropped.
  6. What does it mean that a simple trans oil change, with I dunno what quality of fluid (Jiffy Lube), made such a dramatic positive effect?
F a i l u r e S c e n a r i o
Recent 12 months:
Upshifts have had minor intermittent irregularities (most shifts are normal -- on most outings never happened even once -- an occasional slight clunk). During recent 3-4 weeks, clunks more often, about one out of 4 upshifts. The little clunks didn't seem significant to me; I chalked it up to normal wear & tear.

Yesterday:
Began to recognizably slip a little, worst case between 1st and 2nd.

Today:
When first putting it in motion, it slipped significantly right off the line, hadn't yet hit a shift point, it was barely 5 feet of travel when it happened. Then more bad behavior: At the next traffic sig, right off the line it slipped, then when rpm was probably around first up-shift point, the car acted like I partially pulled the hand brake. I would guess it was at the point it would have up-shifted from 1st because I made it across the intersection before it happened. I wasn't looking at the tach at that moment, but I didn't hear any significant drop in engine rpm - still pretty low rpm at that moment, and the drag was so brief (~~2-3 sec) but it's hard to tell.

Took it to closest lube joint for a trans fluid replacement. Fluid level was still right at 'fill-to' when I brought it into the shop. Asked the tech about fluid conditions: "No odor, could still see some red" :--) ...et voila- it now runs like it did a couple weeks ago (every outing, several upshift clunks)!

- - Bob


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

May 21, 2021, 3:46 PM

Post #2 of 10 (357 views)
Re: Symptoms gone after fluid change, would the following help prolong life? Sign In

I'm not the trans expert but let me clarify one thing.

There is really no such thing as a flush. The term is commonly used when describing a total fluid replacement procedure.

These machines simply rely on the transmission's own fluid pump to pump out the old fluid while it replaces it at equal proportions. It taps into the cooler lines with one in and one out.

The biggest concern with doing that on a high mileage vehicle is that the new fluid has a high concentration of detergent in it which can loosen up solid sludge that is currently sealing many pressure seals.

The upside of it is that it cleans valves and helps them work better.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

May 21, 2021, 5:01 PM

Post #3 of 10 (347 views)
Re: Symptoms gone after fluid change, would the following help prolong life? Sign In

I'm not a specialist either but had to know fundamentals about how they work, wear etc. pretty seriously.
I'm a bit lost if now a 3rd place (twice in a month or so) changed it again or just looked at it?
What do you mean by a "Lube Place" vs trained techs?
I don't like to bash people or these places they're motive is fast isn't in my vocabulary for such risks of a mistake. The one you named is old as a biz TMK don't hire fully trained techs rather teach the way to things fast and furious. That doesn't make sense for trans anything nor even oil changes IMO.


I understand people are busy and fast is attractive so will leave it as a poor choice for the costly things in a vehicle.
One last is a question is what did the fluid look like before you did it? You say reddish but doesn't take much to make it non reddish so what's left in it really doesn't change the color much If this just snapped out of the issues and is fine now I'm lost.
Just opinion again is not changing filter is probably fine if one was so clogged up with junk it couldn't flow the game is already lost would be my take on it.


Buy time is a maybe or touching it late bring out the gremlins awaiting,


Tom



gsferraro
Enthusiast

May 21, 2021, 6:25 PM

Post #4 of 10 (337 views)
Re: Symptoms gone after fluid change, would the following help prolong life? Sign In

Hello,
2001 to 2003 Rav4 everyone has bad PCM to the point where they extended the warranty, The bad computer normally takes out the Transmission. 2Nd biggest problem with this transmissions is the geartrain, i haven't seen a good one yet. Changing the fluid may or may not help depending on the problem. If your feeling any slipping or erratic shifting may be the start of something. Do you know if the PCM has ever been changed?


AvantGuy
Novice
AvantGuy profile image

May 21, 2021, 6:29 PM

Post #5 of 10 (337 views)
Re: Symptoms gone after fluid change, would the following help prolong life? Sign In

Thanks Tom

Yes, I read an old post by Gary where he wrote "There's no such thing as a trans flush". I only used the word "flush" to distinguish it from what was done today, which was just a drain-then-fill.

Don't worry, I know very well that these national franchise joints are the lowest of the low. This oil drain-and-fill is the only thing I would have them do, especially a transmission, engine, or drive train! They probably use the cheapest, junkiest fluid available. However, because the slipping worried me big time and I didn't want to drive another mile without at least getting new fluid in there. My regular mechanic is backlogged for a week. I'm 76 y.o. and have no tools and no longer have a body (scoliosis-ridden) that will allow me to crawl under anything, even just to pop a drain plug. That's why JiffyLube.

I do not plan to leave today's oil in for more than a few days. The next step is where I wanted help from this forum. Now that the trans responded so well to this fluid change, I intend to replace the fluid again, virtually right away. Getting it done at a fast food place was an emergency stopgap. I figure this new oil will help remove residual old oil, is my thinking. Then next week when I do the repeat oil change, I figure that outta get it closer to 100% fresh new oil in the trans. Do you agree with that, Tom?

So my most short & sweet summation of my post is this:
  • I'm here to get your advice on the best method to do the repeat fluid change next week.

Yes, I'll take it to a real tech. I'm leery of going to a franchised transmission shop where I know they'd love to sell a rebuilt.

Thanks again, B o b

[edit] That was to Tom, sorry HT. Replying now to yours...


(This post was edited by AvantGuy on May 21, 2021, 11:22 PM)


AvantGuy
Novice
AvantGuy profile image

May 21, 2021, 6:55 PM

Post #6 of 10 (328 views)
Re: Symptoms gone after fluid change, would the following help prolong life? Sign In

HT,

Nice, that's nifty (using the transmission's own pump...). I know for sure that was not done today. It was all "manual", as he called it. Is there a name for that procedure (so I can ask for the right thing)?
Oh, would they have to drop the pan for that (tap into the cooler lines)?

New fluid with detergent... Is that true with any brand and type of trans fluid? I like the upside, but fear the downside. At 170K miles, is this basically a coin flip to choose the best method?

Oh, so if any fluid I use has detergent, would it eventually dislodge the sludge anyway or is it the added pressure from the pump method that changes the game?

Thanks very much HT,
B o b


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

May 21, 2021, 7:01 PM

Post #7 of 10 (322 views)
Re: Symptoms gone after fluid change, would the following help prolong life? Sign In

No, it's the detergent that dissolves the sludge. The problem is that is some cases the sludge is holding the trans together.
Most shops mistakenly call it a flush, even though it really isn't. Some call it a fluid exchanger.

No, you don't have to drop the pan. You tap into the cooler lines at the radiator.

Usually Toyotas have drain plugs so it makes a drain and fill pretty easy.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



(This post was edited by Hammer Time on May 21, 2021, 7:03 PM)


AvantGuy
Novice
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May 21, 2021, 7:10 PM

Post #8 of 10 (318 views)
Re: Symptoms gone after fluid change, would the following help prolong life? Sign In

Thanks gs,

I know that the ECU has never been replaced, and I don't think the PCM has either (is it one piece, or in a separate housing from the ECU?)


Quote
Changing the fluid may or may not help depending on the problem


As I wrote earlier, the fluid was changed today and it improved it tremendously. The slipping actually went away! I'm asking about changing it again in order to start at 100% new oil rather than 70% new fluid mixed with 30% old fluid.

Cheers,
B o b


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

May 21, 2021, 7:37 PM

Post #9 of 10 (312 views)
Re: Symptoms gone after fluid change, would the following help prolong life? Sign In

ECU and PCM are both the same exact part.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



AvantGuy
Novice
AvantGuy profile image

May 21, 2021, 11:14 PM

Post #10 of 10 (297 views)
Re: Symptoms gone after fluid change, would the following help prolong life? Sign In

Thanks everyone for the education!
Cheers, Bob.






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