Automatic transmission service questions...

[MudbogPete]

My 4 runner has 100K on it. The tranny fluid was changed out at 50K miles, and I figure it is time to do it again.

I was going to buy a filter for it, but surprisingly the Toyota dealer said he wouldn't even bother with it since the filter is more or less just a screen. ......... rather, just replace the fluid.


Does this sound right to you ?

Also, is there anything special about the fluid, or will any type of ATF do ?


Thanks for any help....

 

[MudbogPete]

....Yeah... alrighty then.

I just drained the fluid and installed Mobil one synthetic Dextron III ATF.


I will update if it blows up later on.......

 

[TSP-MIKE]

The best thing to do is to take the pan off and put a new filter on. That is somewhat important because if you see a bunch of metal particles, that means that your tranny might go anytime. That will most likely not happen because those transmission are pretty much bullet proof! Then i would go to the dealer and get them to flush the tranny with toyota ATF. Why toyota? Because it was made specifically for toyota, and nothing else is better.

FYI Toyota buys there engine oil from Mobil. It's a synthetic blend. I don't know about the trans fluid. But you made a good choice on the Mobil 1 ATF.

Mike

 

[98 Joes]

I ask the same question of my local dealer and was told that the filter is a fine screen. I did some research and found it that is true. Also the replacement filter from Fram is a screen, I thought, 'cool, I'll buy a replacement filter to install and clean the old one and then I always have a clean filter on hand.' The dealer also doesn't use a gasket on the pan. They use some sort of silicone sealant (that they were out of). Always my luck.

 

[TSP-MIKE]

Just goto any auto part store and buy the black silicone in the tube. Apply an 1/8 bead on it and that's it! You don't need to put too much on there because when the silicon touches the fluid it expands!

mike

 

[98 Joes]

Thanks. I did my filter and fluid change today. Book doesn't tell you that you need to undo the front sway bar mounts. It's easy though. And I didn't need to remove the bolt from the dipstick bracket either. Oh well. you live and you learn. I was surprised to see magnets installed in the pan. That was cool. No metal shavings on them so that boosted my confidence in the transmission. I installed a new filter (screen, really) and I used the supplied gasket. For a sealant, I used Hylomar. I've used this stuff for years on airplanes and never had a leak. It doesn't harden and that makes it easier the next time. Someone had used some sort of red/pink sealant that got hard as a rock last time. It took me an hour to clean that crap off. Anyway, it's done and it's shifts like new. I'm a happy guy now.

 

[TSP-MIKE]

From the sound of it you did not use a toyota filter. Not that is matters but. Aftermarket seems to make gaskets for stuff that doesn't use it, like the gasket you put on your transmission. The transmission pan is made so that you're not suppose to use a gasket. By using the gasket you just warped the sealing surface of the pan where the screws go in. And i really don't want to break this bad news, but it'll leak soon. That "red/pink sealant" is the toyota sealant, it's very hard to take off, that's why i suggested to use that black silicone. It'll work like the toyota sealant but it's easier to take off.

Mike

 

[98 Joes]

I've given this a lot of thought over the past week and I want to address the last message (this will probably will be my last one also).

1. If you read the manual, some of the automatic transmissions DID come with gaskets installed. Book says to torque them to 51 in/lbs. I did this instead of the 65 in/lbs for a pan without a gasket. DUH!!!

2. At 51 in/lbs, I can assure you that the flange of the pan in NOT been deformed. The gasket is not squeezing out, therefore there is not that much force being applied to the face of pan. Certainlly not enough to deform the mating surfaces.

3. Though modern sealants are a wonderful innovation, they are not the ONLY solution to every problem. A fiber gasket with Hylomar on it will seal just about any mating surface. If you've never used Hylomar, don't condem it as inferior to silicone. Hylomar sealant was developed by Rolls-Royce engines to seal a gasketed surface under all conditions ranging from -50 F to over +300 F. I'm confindent in using it for over 25 years to seal all kinds of aircraft engine assemblies, that it will work fine for my lowly transmission pan also. After just over a week, it is sealed perfectly. Not a speck of leakage. I also know that when it comes time to pull the pan and replace the filter/screen, I won't be needing to scrape off a bunch of old, hardened sealant.

So, before making broad statements about how someone has done ALL the wrong things, try considering the point that there might be other ways of accomplishing the same task. Who knows, you might even learn a new trick or two.