My Transmission Pan Adventure

I use a Slippery pete pump, the one that fits quart bottles is great, fills super quick. I use Toyota WS. The check temp for 5.7 is check is 99-11 and the 4.6 is 127-138.

Im Just asking what exactly do you think is going to happen. If I dont use stainless the bolts with corrode and snap off and getting them out can require drilling if you dont have nub to grab and even then sometimes the nub snaps. If I use stainless with anti-seize, what is going to happen? Think about it, its a 100% chance that the OEM bolts will corroded and get stuck. The chances of what you are referring to with anti-seize applied is what, slim to none? And what then, the bolt gets stuck, just like the OEM ones already do? Sounds to me like you are just being a contrarian here.

 

Anti-seize will limit corrosion to an extent, not prevent it. Once you start screwing in the bolt there will be metal to metal contact. And the difference between a OEM bolt and a SS bolt getting stuck in aluminum is way different. The SS bolt will more than likely ripe out the trans threads since it welds itself, kinda like I said, to the aluminum. As me how I know. And drilling SS vs an OEM bolt is also totally different. Like I said, do with the advice/info as you please. I have dealt with enough SS and aluminum to know that I wouldn’t mix the two together unless it was a last resort. I prefer the lesser of the two evils. And to call me a contrarian would mean that the majority of people agree that there are no issues with aluminum to SS contact, which isn’t so. Have a nice day.

 

Yes, the majority of people and sources believe there is no issues with aluminum and stainless steel fasteners being used together, especially with anti-seize. For the every source you pull saying the opposite I can pull double. I understand your experience with boats on salt water, but while handling like one, the Tundra is not a boat and you dont have experience with what happens to cars exposed to salted roads. You make it sound like aluminum just touching stainless is going to cause the bolt to sieze. Stainless and aluminum are not kryptonite and Superman. With the amount of experience you have with aluminum and stainless steel fasteners it would seem it must be pretty common for them to be used together. Have a nice day as well.

 

https://www.tundras.com/threads/2014-transmission-maintenance-question.57617/page-2#post-1521266

Read from post 52-56.

I went with grade 10.9 when I changed my filter (had the same amount of metal shavings in it as yours, and mine had around 173k?)

@JohnLakeman is a great engineer, although he hasn't posted in awhile, he's very highly regarded in his field (I worked in one of the refineries he worked at before).

Personally, I won't be touching the bolts in my trans pan again, it's unnecessary. But I know the feeling of having to tinker with something, fix something that's not broken, etc. I'm guilty of it myself. If you absolutely feel the need to change them out, get a higher grade steel bolt. Use tons of anti seize, hit the tops of the protruding bolts with fluid film every now and again to prevent rust, although with a higher grade bolt, even if it's rusted, it shouldn't be a problem, the bolt is stronger than the original grade so it's less prone to breaking. The bolt that I had break on my truck wasn't rusted, the bolts are just weak. Food for thought.

When I change my trans fluid (I have a trans cooler) I drain and fill the pan, then I disconnect the return line and drain 2qts a time till the fluid looks new, then do another 2 qts just to be safe. 16qts maybe.

If you wanna use stainless bolts, by all means, use them if you feel comfortable with it. I don't personally agree with it, but I dont know everything there is to know about metallurgy either, as does anyone on this forum ( unless we have a metallurgy guru I'm unaware of)

 

I just came back from one of the best transmission shops here in Miami. The mechanic,"How is your truck shifting ...good? Ok, bro I've been working on these things for over 30 yrs. Don't worry about the filter...especially if you're not having any issues now. Did you change the fluid? Great. I'll see you @ 250-300k."

I get it's a mixed bag of opinions to "change" or "not to change" the filter, but For hose of us who have all the bolts frozen yet have a relatively low mileage transmission (73K), fresh transmission fluid, no shifting issues… It simply a better idea to not incur a big cost for having the bolts all drilled out with the possibility of worse, and keep on trucking.

 

I'm also in SoFlo (Miami). My Tundra came from the snow belt, so yeah... the bolts are all frozen in there. Just had a very experienced transmission mechanic tell me simply to not worry about the filter. If the fluid is fresh and there are no problems shifting… He said simply not to worry about it especially with low mileage I have (73K). I still wish I could get into it… But it seems to be such a mixed bag on peoples opinions of whether or not the filter actually needs changing if your tranny is pristine (and even if it's not, too ).

 

Check post #79 in the thread @Sumo91 linked above. It’s more of a screen than a filter.

 

I had no plans to change the filter, I only did it because I needed to drop the pan anyways to extract the broken bolt. Not sure if you read the OP or not. I would definitely recommend just leaving the bolts and the pan alone unless brand new or never been around salt. Not worth the headache.

There's a photo in the OP of the filter opened up. it's filter media that works similar to a vacuum bag.

 

I wish I'd known that before I was up at the crack of dawn and had driven though 5 different school zones to get to the mechanic lol. I'll have a wee look @ the OP. I'm in Miami, but the '07 (w/ 73k on it) was in effen Wisconsin. Enough salt for them to have a serious undercoat. It's a very cool cherry-ish reg. cab. Love it!

Thank you!

 

I am also in S. Fla. I really don’t know if to call it a filter or just a bag. I mean its probably not filtering microns but it does filter bigger particles. I personally just stop to oil changes. I just redid my trans cooler and the was already darker than the OEM color, which is expected. I have already done 1 4 qt change and did a 2 qt change when I added the trans cooler. When I hit 30k I will do like a 8qt change then nothing till 60k. When I do the 30k, just for kicks I will drop the pan and check the magnets.

 

Great OP article. I live by the water in Florida and when I bought a new boat with an outboard motor, my marine mechanic sprayed everyone of the bolts on the new engine with a product called Boeshield T9 (developed by Boeing). It sprays on like oil and dries (somewhat) to a sticky residue. Most Florida boaters know about this and use it as a corrosion preventative. Not sure if it would help to prevent galvanic corrosion between the SS and aluminum parts or not. I can't see it hurting though. I have used it on SS threads going in to aluminum and haven't has any locking issues yet. Down here, you can get it at Walmart. Good luck.

 

I am a Mechanical Engineer by trade. I have experienced Aluminum to 304 Stainless galvanic corrosion in automotive and industrial applications.
I am a seasoned shade tree mechanic who has dealt with his share of stuck, stripped and broken bolts. I live in Michigan

Get those stainless steel bolts out of your transmission or you will be drilling and tapping every one of those holes! You may even end up drilling out every one of those bolts because they will not back out of the hole. It will happen faster than you think if you expose that mix to salt.

Here is a handy chart. I very rarely use stainless hardware as a result. Not only is it a bad screw material from a strength standpoint but it reacts with nearly every application that would want to use it in. Steel is not much better than Aluminum. I learned this the hard way when I used stainless to attach the license plate to my wife's van. The holes in the plate got really bit and the screws/bolts corroded into the weld nuts on the van.

Notice that 304 (most stainless hardware) is on the very bottom and aluminum and steel are on the very top. The bigger the voltage potential between the two metals the faster/more they react. The less passive metal (higher up on the chart) will be the sacrificial metal. Your transmission will rot out and the bolts will be just fine.....

 

I just thought I would update everyone on this since it was a lively debated issue. I replaced the bolts and coated them with anti-seize one year ago. Took all the bolts out today and no sign of corrosion.

 

I think the concern is corrosion on the transmission, not the bolt. The transmission with SS304 bolts will become a sacrificial anode.

 

X2. Very bad having SS bolts in AL threaded holes. They will eventually become one…

 

I do not think anyone will convince op that ss to alum is bad.

 

https://www.fastenal.com/content/feds/pdf/Article - Corrosion.pdf

 

You guys can say what you want but from actual real world observable testing I have 0 issues after one year with the bolts in there meanwhile the OEM bolts after two years where corroded and snapping. I'll make sure to keeping checking them every year just to respond to this thread and if one "becomes one" with my transmission I will be honest but obviously no one responding has snapped off one of these bolts before if you think the OEM ones are any better. Just search Tundra transmission pan removal and see all the horror stories of them snapping and needing to be drilled out. Just one video for example. Feel free to leave the OEM ones in there and remember this thread when you're under there trying to get a broken one out.
https://youtu.be/LraQqGHTmKo

 

Wow thanks! This is probably the most helpful thing posted in here. Looking at that chart I am at a 2 meaning "The corrosion of the base metal is marginally increased by the fastener." So I have marginally increased the chance of corrosion but also as stated in the article adding a coating like I did with anti-seize will help negate that. Considering the OEM bolts corrode away into the transmission like crazy I see 0 evidence besides anecdotal naysayers that this is going to be an issue.



It would seem maybe people in this thread have mixed up what the issue is, if you look at the chart, if you use aluminum fasteners in a stainless base "Corrosion of the fastener is increased by the base metal." But when done in reverse its not really an issue especially when adding anti-seize that is made of aluminum like Permatex.

 

Your vehicle sir, do what you feel is right

 

This chart is talking about passivated SS. Your bolts are very likely not passivated. Especially if they are nice and shiny.
Soak them in lemon juice overnight if you want them passivated. They will not look as nice but there will be a nice non conductive passivated layer to help you out.
Yes, never-seize will help. But it would also have helped the original bolts. So you are not really comparing apples to apples here.
SS bolt will always look good. That is not what you should be looking at. You need to be looking at the threads in your transmission. This is not an easy thing to do on a hole that small and deep. It will start with some minor pitting. As the corrosion grows you will see some white corrosion of the aluminum. At this point you have a big problem. Eventually you will not have threads left. The bolt will not get stuck, it will just spin in the hole.
Do what you want.
If it were mine I would buy a good zinc plated or better yet a zinc flake coated bolt and replace them when they start rusting. Let the small cheap part be the sacrificial member. They are cheap and easy to replace. The transmission is NOT. Yes, I would also use never-seize.
https://www.mcmaster.com/products/zinc-flake-coated-screws/

 

OP went from "it definitely corrodes for everyone" to "it may become corroded", I see it as win-win. There wasn't a single road grime faced zinc-plated bolt in alu blocks in my older vehicle that went out without a torch, dremel, screw extractor, drill, helicoils and some profanity. I replaced some with SS304 + alu-based antiseize and never had any problem years after. The rest new zinc-plated bolts got alu antiseize and not showing any sign of stubbornness as well.

 

Good point with acid.

I lately use Noxudol 700 on all threads (+ reduce torque as it is a wet torque now). It is loaded with corrosion inhibitors and creates some sort of oxide layer on both mating surfaces. I.e. bolts turn dark and do not rust when cleaned dry with brake cleaner and left in dump location.