Driving while transmission over-filled

I purchased a 1994 Previa S/C AllTrac LE this week, and carefully checked engine oil and coolant levels before driving home (50 miles), but I foolishly relied on the fact that the seller showed me a receipt indicating that the vehicle had just had the transmission checked and fluid changed by her regular shop (NOT a Toyota dealer). By the time I got home I noticed that there seemed to be a slight growling sound in the transmission at low speeds (10 to 25 mph), so I checked the transmission fluid level immediately upon arrival, when it was hot. To my astonishment, the fluid on the dip stick was about 4 inches above "hot full"!! The next morning I drained the excess fluid -- exactly two liters! The fluid is very dark red in color, but does not seem to smell burnt. In a two-liter clear soda bottle I cannot begin to see through the fluid. Considering the extent to which I and other prospective purchasers drove it before I checked the fluid level, I estimate that the vehicle must have been driven with transmission sump so seriously over-filled for 4 hours minimum. What are the most likely indications of possible damage for which I should be especially vigilant? Of course, I will want to change transmission fluid very soon (I plan to use AMSOIL Multi-Vehicle ATF), but my understanding is that, short of removing the transmission, the only way to see that MOST of the fluid is new is to flush the transmission with the new fluid so that the old fluid in the torque converter is flushed, but the high price for doing that would be almost prohibitive for me. Is there any less expensive way to change more than about half of the ATF other than either to flush with new, expensive ATF, or to change fluids two or three times over the next year? Any advice for this first-time Previa owner (who is mechanically adept, but is NOT a professional mechanic) will be most sincerely appreciated.

It's very difficult to say with any certainty if this caused damage or shortened the life of your transmission. Usually you can get by with an extra quart or so with no ill effects. With serious overfilling (like what it sounds like you had), if the ATF gets high enough to contact the gears, they will whip the fluid into a foam. Foam is basically fluid mixed with air. The problem is air reduces the volume of fluid that's pumped and since it's compressible, the result is low fluid pressure & reduction in lubrication to the critical areas. Automatic transmission fluid is also used to transfer heat out of the transmission & when it's mixed with air it's less dense and less effective doing that. This can lead to slipping/overheating of the clutches and if driven this way for too long can burn or damage them. When clutches fail debris from them ends up in the fluid. If they slipped excessively the fluid will usually be dark red or brown and smell burnt. Sometimes clutches don't burn, they just start falling apart. This is usually evident by fiber type debris (lots of it) built up in the strainer/filter area and/or laying in the bottom of the pan. If there's lots of debris, then you have a problem and the transmission will likely fail soon. If it's clear, then you are likely okay.

I would recommend removing the pan and replacing the strainer. Inspect the old strainer carefully to see if it's got debris in it. While the pan & strainer are off, start the engine, put your foot on the brake, and cycle through the gears, then back to park (this will help purge a little extra of the old fluid out). Try not to run the engine for more than a minute with no ATF in the transmission. After you get the new strainer installed and the pan back on, fill to the correct level with the Amsoil ATF. I like Amsoil synthetic ATF and it's what I prefer & run in the vehicles I care about. It's compatible & will mix with the standard Dexron III that remains inside the torque converter. Amsoil synthetic does not require a thorough transmission flush. Personally I don't like power flushes and would never pay to have one. Knowing what I know about how most automotive shops are run, I would worry about the flushing equipment not being correctly maintained and ending up worse off then I was before (who knows what's been run through there). If you change the transmission fluid every 60k miles or so you'll never need one. If you just want to make it a higher percentage of Amsoil ATF, then drain & replace fluid a couple more times at intervals you can afford.

In regards to flushing transmissions, a couple of times I have had rigs come in with water/antifreeze mixed with the ATF (caused by a failed trans cooler inside the radiator). In both cases I drilled an 11/32" hole in the torque converter to drain. After it drained I tapped the hole for 1/8" pipe thread and put a pipe plug in it. This is probably too extreme for anything short of severe contamination, but it's an option to power flushing.

Thanks for posting here on TVT & let us know how it all turns out. Good luck & enjoy your new Previa! Tim

Here's what clutch debris looks like when it ends up in your strainer. This is an example of what you DON'T want to see:

http://i8.photobucket.com/albums/a23...n/IMG_0818.jpg

http://i8.photobucket.com/albums/a23...n/IMG_0816.jpg

This strainer was removed from a correctly functioning transmission during routine maintenance. This transmission was likely less than 1k miles away from complete failure and was not returned to service until AFTER it had been rebuilt.

Apparently I dodged any bullet: while the transmission pan had a very thin coat of sludge, there did not seem to be debris, and the filter seemed quite clean, with no sludge on it at all in the portion that one can see through the little "window." The transmission pan had no magnets at all, but there are 4 little indentations for them. Tim, what's your opinion about magnets: should I put four into the pan? Somebody online mentioned rare earth ones. What say you? Of course I'll replace the filter, and install AMSOIL Multi-Vehicle ATF, and drain/refill ATF 2 or 3 more times within the next year or so, eventually ending up with mostly AMSOIL. Is there any filter, other than the one available from Toyota, that is to be highly recommended? Thank you most sincerely for your invaluable coaching, Tim!

Glad to hear you lucked out. And to think somebody paid to have that done to their vehicle :no:. I would want magnets in there. Try to stay with same basic shape & height as originals. Rare earth magnets have more attraction, but they can also fracture and have a thin nickel plating. Probably nothing in this environment that would cause them to fracture or lose their plating, but this would be the only concern I'd have. If you use this type, inspect carefully before putting them there to be sure the plating is not lifting and there's no cracks/fractures. The only filter in the transmission is that strainer (not really a filter, just a super fine mesh screen). It could be cleaned, but I always replace. I've used both Toyota and aftermarket and both appeared to be of the same quality (could not tell the difference). Based on that, I usually just get the cheap ones off www.rockauto.com or whoever has a good deal on them. If you go Toyota, you need to buy the strainer, strainer gasket, and pan gasket separately. If you go aftermarket, some manufacturers (like Fram) will supply everything you need in a single kit. Tim

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Originally Posted by Melisander Wildberger

Apparently I dodged any bullet: while the transmission pan had a very thin coat of sludge, there did not seem to be debris, and the filter seemed quite clean, with no sludge on it at all in the portion that one can see through the little "window." The transmission pan had no magnets at all, but there are 4 little indentations for them. Tim, what's your opinion about magnets: should I put four into the pan? Somebody online mentioned rare earth ones. What say you? Of course I'll replace the filter, and install AMSOIL Multi-Vehicle ATF, and drain/refill ATF 2 or 3 more times within the next year or so, eventually ending up with mostly AMSOIL. Is there any filter, other than the one available from Toyota, that is to be highly recommended? Thank you most sincerely for your invaluable coaching, Tim!

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the A340E is supposed to have magnets... the idiots who serviced it probably threw them out
there are supposed to be 3 magnets in the A340E/F (the A46DE/DF has 2 but there's a place for a 3rd one).... you can buy replacements from toyota under part number 35394-30011

for a high mileage vehicle, I rather use Valvoline Maxlife.... it is fully synthetic and has additives to ensure firmer shifts and seal conditioners... that is what I use on my old toyotas... shifts smooth but solid... much cheaper than amsoil

Thanks very much for your words of wisdom, TheMAN! Meanwhile, I've found Cascade Transmission Parts way out in the country in western Oregon, and its proprietor identified the transmission filter I need, which NAPA was unable to do. Oddly enough, it's the one that JEEP used in its version of the A340F, so I must assume that at the beginning of its supercharged Previa run in 1994 Toyota must have adopted that same transmission, tweaking it with a slightly different filter design the following year. As everyone knows, the Toyota dealers' prices are so absurdly inflated that, when it's not absolutely crucial to get an OEM part that is demonstrably superior, I go with other reputable manufacturers and suppliers.

don't panic... you never have to buy local!
order from rock auto.... cheap prices, and if you google, you'll find a 5% coupon code you can use that works towards the cost of shipping... there's a far better selection on rock auto and as such you can get quality parts instead of a limited selection of garbage from a local parts store

for important stuff though, I try to buy stuff from toyota... I order online... I have used conicelli toyota many times (their site is called partznet or something like that), and while their web catalog sucks, it doesn't bother me because I look the stuff up myself first and order by part numbers... the filter part number is 35330-30011... you have to order the 3 magnets anyway, so you might as well get the filter too at the same time :)
there doesn't appear to be a pan gasket, it's supposed to use RTV sealant... in the past, toyota used gray sealant but they have since switch USA suppliers and what you buy here in the states are now black sealant from the dealer... so you can choose to buy the "toyota black" if you want, under part number 00295-00103... or if you're going to get aftermarket, use a gray sealant, such as permatex ultra gray, don't use black as it doesn't have the same strength as the gray... you can always look on ebay of course ;)

the A340E is actually borrowed off the 4Runner from what I understand, but whatever... Aisin is who made it, and they're known to supply to different manufacturers

Thanks again, TheMAN! More than one person has suggested RockAuto, so I'll be dealing with them in the future. Regarding the transmission pan seal, because I'll want to take the pan down for inspection and more thorough emptying within just a few months, so I can achieve a higher percentage of the new ATF, I think I'll use a neoprene re-usable gasket for now, and then when I'm satisfied that everything is running well and I have a good concentration of new ATF, I'll use a more permanent cement on the tranny pan. Again, many thanks for your courtesy!

there is no need to remove the pan any time you just want to do a drain and fill... there is a drain plug on it, unlike domestics :)

The idea of taking the pan down from time to time was more to inspect for debris, since I don't know much about the history of the car, and the owner didn't keep a maintenance record. I still have to get magnets tomorrow, and car parts places don't seem to have them. I may have to go to a special magnet store in Portland if I can't find any at a hardware store. Toyota could get them -- for $11+ APIECE!! I'm just not going to spend $34 for 3 simple little magnets. I did pay $33 for a thermostat from them today, and $5 additional for its gasket! I think I have contributed sufficiently to Toyota's welfare for now. Many thanks again, TheMAN, for your reasonable advice.

dealer mark up FTL... true MSRP price on the thermostat is $21.66 and the o'ring is $5.60, so at least they didn't eat you up on the o'ring... still, I wouldn't pay a dime over MSRP considering typical MSRP price is about 60% over dealer cost
you really need to buy your toyota OEM parts from a better place... even with paying $8 USPS shipping from conicelli (for orders below $25, orders over $100 have free shipping), you would've came out ahead as they will sell to you at wholesale price, which is 20% off MSRP

You're absolutely right! I'm going to find a better place for those Toyota parts that HAVE TO BE OEM. I inquired as to the price of transmission magnets at the dealer (Capitol Toyota, Salem, OR), and was quoted $11 PER MAGNET!!! I stopped by a transmission shop and got them for $1 apiece. That sort of greed on the part of Toyota is simply beyond the pale. I'll look into Conicelli. Thanks again for caring!!