3rd Gen Differential and Manual Transmission (6MT) Fluid Change

I agree. Redline is good stuff. I was pretty happy with it except sluggish shifting in cold weather, but then I got stupid cause everyone raves about how great Amsoil is, and decided to try that. The Ford is better than Redline for the Toyota transmission, but I am not saying by any means that the MT90 is bad stuff.

 

What's the difference between the MT oils?

 

Similar to differences between engine oils. Usually, not much.

Although, in the case of MT oils, the base and additive package can either help or hinder shifting. The OEM MT oil in the Taco feels great, but I don't like what @Omar RVA's UOA reported. In the case of the saab, many folks were bouncing between the various MT oils trying to fine one that would give good, quality shifts and eliminate the problem of getting into 1st from a stop.

 

And some of the oils, like the Amsoil, make it tougher to get into reverse, especially if you have the URD short throw installed.

 

So is it better to just stick with OEM? I haven't had any problems with my shifting except the rough cold starts.

 

Redline is quite a bit better than OEM (noticeably), the Ford Motorcraft is even better than the Redline. I did not like the OEM fluid, it was too easy to grind gears.

 

When i had my 2000 Tacoma i swapped everything to Amsoil, all was fine except the transmission as it refused to go in 2nd gear when it was cold.

 

My experience with OEM was that N to 1 and 1 to 2 were awful feeling shifts for me. Often, I would get locked out of 1 (from a complete stop) without shifting down to 2 or giving it a bit of rev first. Based on research, the Ford motorcraft stuff seems pretty special (specifically for clutch/brake fluid applications) but I didn’t go that route; I do intend on changing the clutch/brake fluid to motorcraft when it’s time because I hate how my clutch feels under 32 degrees. I was torn between redline and Amsoil and, without going down the rabbit hole, what I read showed redline seems to offer slightly shorter service intervals (possibly at the trade off for slightly better performance).

I think what folks will find is that MUCH of this is subjective; without knowing every material property in the trans and how that interacts with oil + additive properties in the specific use case.

OA

 

Well thanks for that info. I'm trying to learn as much as I can about this vehicle and anything that can help improve the performance is good for me. Now that you mention it, I do have problems with going from 1-2 in cold days. It really hops on me and on top of that, I have been locked out of 1 a few times.

 

Exactly right man.
I have followed this thread with interest, just to see where it took different folks.
While I applaud some of you for doing your due diligence and making your decision based on facts as you understand them, you must do so with a caveat, as said in this quoted post.

Please, before you decide to change ANY fluids (other than washer fluid lol) to a different spec or a different brand, remember that there was a whole team of engineers working with the team who designed these components who ultimately spec'd out what to use. They know exactly the performance of each of these fluids will have with their selected components. They have tested and tested some more to determine their results. They have some of the best engineers in the world analyze these results. Their goal is reliability and durability within the constraints of their design. Also, their final spec is not subjective. It is based on real world results.

Also, remember that Toyota does not own a refinery. They issue their specifications to several vendors (Mobil, etc) and, as long as their fluid passes their specifications and they are commercially attractive, they go with the guys who have the right fluid. Those vendors like Mobil, Valvoline, etc then put their oils and fluids in Toyota branded bottles. So if you think one brand or another is better than Toyota OEM fluids, think again. It could be your favorite brand is already in the Toyota bottle! It's this way for all their fluids, not just motor oil.

Lastly, while bobistheoilguy is a great resource for laymen, it is like kindergarten for the guys who do this for a living. And unless you are a world class Tribologist and have access to the actual engineers who designed these components, then you are only guessing with your choice and could conceivably shorten the life of these components if you choose wrong. If you take nothing else from this post at least take this to heart: There is no perfect fluid spec for all applications. Everything is a compromise. However, these guys have tested pretty much every conceivable condition and chose the fluid that worked best for these varying conditions. You might choose one that helps shifting in cold, only to find out it causes excessive wear under load or when it gets hot.

Just wanted to throw this out there. I know this process intimately and have worked with top talent in my profession. I have almost 30 years experience as a design engineer and some of these guys make me feel like I should be in that kindergarten class lol.

 

You sound like an engineer. This is how it works in an ideal world, but in real life, the marketing and finance department wins out, which is why we have stuff like Ford not re-designing a car to not blow up when rear-ended.

 

I am, and marketing and finance does not "win out" as much as you think. Sure, cost is super important, but what is delivered for that cost is super important too.
Question: Why did you buy a Toyota? Because it's fast? Efficient? Beautiful? Can haul heavy things? I'm sure the answer is "no" to each of those things lol. You bought it because it's looks rugged and it has a pedigree of reliability and durability, just like I did.
Those categories above are real reasons people buy what they do. Some want efficiency, or beauty or speed or to be able to haul heavy stuff.

Toyota absolutely knows why people buy their products and it is reliability and durability when it comes to their trucks. If marketing and finance tells them they can only spend X on the total vehicle, they will spend it on the durability part, not the fancy interior part. That's why we only get the go pro mount instead of the camera too lol. The rest of the money went into the drivetrain! Not really but it works that way in real life.

 

While I agree that there is a whole team of engineers deciding on what’s what to use and why, one thing I feel thay gets overlooked more often than not is the mentality of manufacturing as a whole. Gone are the days where building things to last trouble free for 500k miles is the goal. I’ve owned/seen so many vehicles where parts are designed to only last a certain amount of time by manufacturers across the board. Just like auto manufacturers designing completely closed coolant systems, or the new taco’s not having a trans dipstick. They want you to come to the dealership for service eventually. Why else would they do things like that? Look at how many older generation Toyota’s go well above 250-300k with little issue. Clearly there wasn’t a problem in the past in allowing us to easily check/add our own fluids and service our own parts. That takes money out of the dealerships pockets. Only reason to even consider that type of design. Also, I work directly with engineers everyday. The stupidity that comes out of their mouths sometimes is absurd. So saying “engineers” came up with it doesn’t carry much clout with me. One of the parts I weld has a stated maximum tolerance gap at 4 mill. I consistently get parts I can stick my finger in the gap and wiggle it around. I’ve complained and they tried to figure it out. They couldn’t come up with a solution so what’s their fix? Modify the print to allow concavity in the weld so I can fill it and weld it. I weld a very critical part to a very large, expensive machine, and I wouldn’t come even close to doing something like that if it were my own but it’s above my pay grade.

 

Yes, some engineers are stupid. Just like some welders are stupid. Some doctors are stupid. All lawyers are stupid... you get my point and I understand.

Its very easy to answer your other questions, like why no dipstick. Do me a favor - google "How many people change their own oil today" and you will get a shocking answer... it's less than 4%. @5 years ago it was like 35%. 50 years ago it was much more. People have gradually lost interest in doing stuff like that. Sure, here on the forum it is a big deal. In the real world? Not so much. That no dipstick thing was customer driven, not company driven.

As far as designing for a life, we have always designed for a lifecycle. We just do it a lot better now than back in the day. As far as old vehicles lasting 500K? That has always been the exception, not a rule. Now, washing machines? That's a different story lol. Those guys have really made those cheap and disposable. We just got a new one. Wow.

Lastly, take a look at how much a new 4Runner cost back in 2001. It's real close to what they cost new a few years ago. Somehow, they took a lot of cost out of it and still gave us some quality. No, Toyota does a pretty good job of giving you something for your money.

My whole point is we can't begin to think we can choose fluids better than they can.

 

Thanks for the info.

Yeah there was a meet at Bass Pro last Sunday, my first time attending one met some cool people scored some almost new black TRD Pro wheels for $350...Wasn’t part of he plan haha

 

Shoot I would’ve bought those on the spot too!

OA

 

Interesting findings.

I switched to MT90 because I used it on my last two manual tranny vehicles and noticed an immediate change in shifting for the better, but when I converted the Tacoma the change was negligible. I was actually pretty disappointed.

I'll have to try the Motorcraft fluid some day.

 

May be a dumb question but how do you clean the pump between the manual fluid and differential?

 

Would a thicker fluid when cold theoretically provide better wear protection?

 

I am going to do mine here soon getting close to 6k.
So 6qts. of GL5 for the front and rear diff's.
GL4 for the tranny....HOW much does the tranny hold, 5 speed?????
Also transfer case?????