High Mileage ATF Change OR Leave Alone?

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484
Location
IL
My '98 4Runner has 188k miles. I've only owned it for 6 months. It seems to have been very well maintained. I spoke to the the only other owner (a woman who drove it 30 miles each way back and forth to work) and she "says" it always had the fluids changed. I spoke to her mechanic, small town, do-it-all type of guy who I do not know. He agrees that she always maintaned it with him, but he does not keep records. The transmission, along with everything else, works flawlessly. My Toyota dealer says the ATF looks to be pretty fresh. However, I'm using it mainly to pull our camper. I've read two thoughts---at this mileage leave it alone, or, go ahead and maintain with ATF change. We have a good Toyota service dept here and that is who would be performing any AT maintenance. Thoughts?
 

lukejo

Thread starter
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484
Location
IL
I should add that I did have the differential fluids changed at the first service...they did not look nearly as clean/fresh as the ATF.
 
Messages
456
Location
Aberdeen SD
I changed the fluid in my f150, while only 130k miles it was original, and that truck has had a trailer hooked to it from new, and 34 foot flatbed, a 28 foot cargo van, or a triaxle dump trailer. Its shifting better than ever. so if its been maintained i see no reason not to change it out.
 
Messages
25,985
Location
Upstate NY
Have the transmission filter changed and a complete ATF fluid exchange, however you want to do that. No need to go to a Toyota dealer. Maybe add a Magnefine inline filter. Install a transmission drain plug if there is not one. Don't believe the "its got xxx,xxx miles so its best to leave it alone advice". Its not sound advice. New ATF is always a good idea unless you are pushing the vehicle into the transmission shop.
 
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3,321
Location
Richmond, VA
My thought is to change it. ATF can look good after 50K miles, but its ability to keep an AT running perfectly may be compromised somewhat. Just imagine it as engine oil that has 3,000 miles - or maybe 9,000 miles because you don't know. I would sleep (and drive) much easier knowing that you have done all that you can to keep it running perfectly.
 
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387
Location
Charlevoix, MI
Changed the original fluid out on a 98 Regal at 166k, still running along beautifully at 195k now. New atf is always good, never a harmful thing, if something goes wrong it was going to go wrong whether you changed the fluid or not.
 

lukejo

Thread starter
Messages
484
Location
IL
Wow--seems to be unanimous. I guess this would be the forum with the best advice on ATF. I'm the over-kill type of guy on fluids, but buying such a high mileage vehicle, I sure didn't want to mess up a good thing. Thanks for the advice. I'll go ahead and plan on doing an ATF change this fall.
 

lukejo

Thread starter
Messages
484
Location
IL
Originally Posted By: daves66nova
Originally Posted By: lukejo
I'll go ahead and plan on doing an ATF change this fall.
Why not right away?
Ha! That's what I mean...it's not exactly a DD, but we are using it heavily to pull the camper during this beautiful fall weather. I expect that we'll work it in in the next couple of weeks. I'll do another oil change at the same time. Coolant and differentials were all changed 2 months ago.
 
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9,105
Location
Houston, TX
Originally Posted By: Brent_G
Exactly. If a fluid change kills a tranny, it was already on borrowed time.
+1 - lot of folklore about old transmissions and fluid changes. Change it...
 
Messages
702
Location
Portland, Oregon
I would do a drain and flush ideally every year and at least every other year. A drain and flush is only a partial flush. It freshens up the ATF fluid enough with additives and fresh oil that it's good to go till the next partial flush -- or hopefully so! I would use high mileage ATF like the Valvoline NexGen High miles variety. It's got seal conditioners and additives suited for high mileage cars. Also I've hear good things of Gunk transmedic and am using it in my 2nd car. Not sure if I buy the old tale that flushing the fluid dislodges and messes up transmission that haven't seen a flush in years. I tend not to. The odds seem far worse on going with the really old worn out fluid. But if you do a drain and flush, keep it simple, don't try pump out more fluid than drains from the pan with the engine off and in park. Getting air in the transmission by running it below minimum is what really can kill it.
 
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3,610
Location
Ponte Vedra Beach, FL
IMO...It's always a good idea to change out the fluids a few times before going to synthetic. I changed out the front and rear differentials along with the transfer case 3 times, each at 40K miles before switching to synthetic. IMO....it takes some time to get all of the worn fragments out of the differentials. I switched back to Toyota Red, after using the generic green for many years. I had a full system fluid exchange to make sure all the generic green was removed. Now, with the Toyota Red in the cooling system, I will drain the radiator once a year and refill it with a 50/50 mix once a year, before winter sets in. After a 3 drain and refills with conventional gear lube on the diff and transfer case, I switched to Mobil 1, 75W-90, full synthetic gear lube. If you use the discount codes at Advance Auto, you can accumulate some quarts of Mobil 1 Gear Lube and ATF for 5 to 6 bucks a quart, over time. Transmission and Power Steering get Mobil 1, ATF, Full Synthetic. I've done the ATF full fluid exchange a couple of times, with Toyota Fluid for the ATF, but now I plan to just empty the ATF pan once a year/20K miles and refill it with new Mobil 1 fluid based what was removed from the drain and any top off needed. The screen in the transmission is usually clean after the first drop and drain with the filter exchange on the AT. Power steering fluid is good to have the pump flushed every 3 or 4 years but you can use the "Turkey baster" method each year to exchange out the fluid for the PS unit. Still the flush method is a good idea....you will be amazed at the color of the used fluid that comes out along with wear particles. Cheers....enjoy your T4R.
 
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5,022
Location
Southeast
ok-- that 4runner may have the infamous AW4 AT. Let's hope that it does. It's been in a few other yota vehicles as well as a bunch of Jeep Cherokees and even 6 months of the first Jeep GC. It is a stout, sturdy transmission that can go a lot of miles. It does not have a real filter-- just a screen. An inline filter would be nice. It does have a magnet sitting in the pan. Only drawback-- it's weakness is that it can generate a bunch of heat, cook the fluid, etc.. It was not a good off-road performer in the larger grand chero-- unless it had extra cooling. so-- that is likely the original AT, and if it was driven nicely, looking at the fluid won't tell you much. If you are going to tow, ADD A COOLER. Change the fluid (don't bother changing the filter, it's just a screen). You can suck it out or do an exchange. Consider a syn ATF. Mine did very nicely with Dex VI. Add an inline filter since it really doesn't have one. This is all assuming you have an aw4. search aw4 on the 'net for casing pics-- you can look at it to identify... Mike
 
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