80W90 Gear oil in Mazda 5 Speed

[bluestream]

I know that the Mazda 5 speed is to use ATF, and not gear oil. The reason for this is mainly for better fuel economy, and for easier shifting when cold.

Is there any reason why 80W90 Gear oil could not be used instead? Manual transmissions used gear oil long before they started to put ATF in. Gear oil has a much stronger film strengh that ATF, and should be better for the Transmission. Anyone have any thought on this?

 

[Robb]

If the engineers designed the tranny to use ATF, why would you want to use something else?

 

[bluestream]

As I said, they wanted to get higher fuel economy, not make the transmission last longer. All they have are bearings and gears in these things. As far as I know there are no special gears and bearings designed for ATF.

 

[dogfriend]

I think that another reason that they chose ATF for that gearbox was for shifting performance. If you use gear oil, the synchos may not function as well, and it may not shift as easily.

If you would like to use a product that provides better protection, but has similar visocity to the ATF, you could try Redline MTL. I had a Ranger with the Mazda 5 speed and I replaced the ATF with MTL at about 12k. I drove the truck until it had 125k and never had any issues with it. It seemed to shift slightly better with the Redline.

Dead Link Removed

 

[JDraper]

I would suspect that a tranny designed to use ATF would have much tighter tolerances than a tranny designed to run on gear oil, and therefore, if you use gear oil, it might not lubricate properly because of it's heavier viscosity. I'd stick with the ATF.

 

[Robb]

All they have are bearings and gears in these things. As far as I know there are no special gears and bearings designed for ATF.

Um, what? As far as you know, what lubricant were there gears and bearings designed for?

As I was pointing towards, the transmission is a low tolerance, high precision piece of equipment. Engineers designed to the tranny to operate at these tolerances with a specific lubricant. Simply sticking in a higher viscosity lubrcant is going to do nothing but cause problems. If Ford thought that they could increase fuel efficiency by putting gear oil in their transmissions............they would have done it.

 

[dogfriend]

Originally posted by Robb
If Ford thought that they could increase fuel efficiency by putting gear oil in their transmissions............they would have done it.

I think that he is saying the opposite of this: He believes that Ford used ATF instead of Gear Oil so they could get better fuel economy. I don't want to put words in his mouth, but I think that he also believes that Ford would trade off some transmission longevity for better fuel economy.

Unfortunately, it is slightly more complicated than that. I'm sure that Ford does testing on all of the lubes that they recommend. They try to pick the best combination of characteristics, but any choice is going to be a compromise in some regard. He is correct that ATF generally does not have as good of a film strength as gear oil would have. But there are a lot of other factors to consider as well, and Ford has picked the best compromise according to the criteria that they deemed important.

If you check out this link:

http://www.redlineoil.com/redlineoil/mtlti.htm

they have a good discussion on characteristics of transmission lubes. It may be biased toward their product, but it seems to be factual and technically correct.

I don't have any financial interest in Redline or any other product, but I did use this product in the same trans with good results.

 

[Robb]

You are correct dogfriend, I read his statement incorrectly. I still believe that sticking gear oil in a piece of equipment designed for ATF is a BAD idea.

 

[NOTAJP]

Originally posted by Robb
You are correct dogfriend, I read his statement incorrectly. I still believe that sticking gear oil in a piece of equipment designed for ATF is a BAD idea.

It's been proven a bad idea. I cannot recall the thread but someone actually put gear oil in a M5R1. Let's just say it didn't last a week. I have over 150k miles on my 5 speed without a glitch. This is the second 5 speed Explorer in my history with over 150k and never a problem. There isn't an issue of reliability with this tranny. The AODs use ATF and cannot last 50k miles. I second using Redline or any synthetic ATF if you are worried about longitivity.

 

[bluestream]

It is certainly possible that Ford/Mazda did design this unit for use with ATF, it is also possible that it may be that all transmissions are designed with the similar tolerences, and could use ATF or Gear oil. I think the only way to get a correct answer is to get a reply from a Ford engineer.

I am sure we could go on speculating all day about this. There is no doubt in my mind that gear oil is far superior lubricant to AFT, which has the viscosity of water. I would aslo guess that most users on the site would give up the loss in MPG if they knew they could safely use the gear oil.

 

[Robb]

If you have no doubt about it, then I say go for it!!

 

[NOTAJP]

Originally posted by Robb
If you have no doubt about it, then I say go for it!!

Hell of an idea! Why didn't I think of that?

 

[bluestream]

Originally posted by Robb
If you have no doubt about it, then I say go for it!!

Well, I do have doubt, and that is why I asked the question, and refered to only an engineer being able to answer it.

I have sent an email to Redline about it to see what they say, and I will let you know if they reply.

 

[NOTAJP]

Originally posted by bluestream
There is no doubt in my mind that gear oil is far superior lubricant to AFT, which has the viscosity of water.

What would make you think that?
Could you also let me know how your transfer case holds up to the gear oil?

 

[bluestream]

Originally posted by NOTAJP
Could you also let me know how your transfer case holds up to the gear oil?

I'm not sure what you are talking about??? Have I offended you in some way?

You seem to have a rather nasty tone to your posts.

 

[NOTAJP]

What I mean is...

If you planned on running gear oil in your tranny did you plan on running it in the transfer case too? If so, I was curious how long it would last.

 

[Derrick C.]

Boy oh boy!!!!

People always causeing trouble on friday nights.

I'm sure NOTAJP is just giving you a hard time. But then again you asked for opinions and got them. Take them as they are. Don't start anything when you don't need to.

As for my opinion......If it asks for ATF use ATF. Asks for gear oil use gear oil. Its kinda like putting diesel fuel in your Ex because a few people said they got better MPGs. Times have changed......things are designed different. Go by Ford spec or just try it and let us know.


And to add a funny joke in here since we all need to laugh........Don't forget to refill your blinker fluid.

 

[bluestream]

I had a chance to read the info on the Redline web site, and it really exposes the weakness of using ATF in a manual transmission.

I think I will try their GL-4 gear oil, as they recommend. Now if I can just find one of their dealers...

 

[NOTAJP]

I took this off of the redlineoil website:

In transmissions which recommend Dexron or Mercon fluids we recommend our D4 ATF which is very similar to the MTL, being a GL-4 Gear Oil also. The D4 ATF will provide better low-temperature shiftability, and the MTL would provide better wear protection for racing use.

Again, let us know how it works out for you......

Their is a dealer here on the board somewhere. You shouldn't have a problem finding a local dealer.

 

[Slick Rick]

A solution to your problem...

Use Redline's MTL. You will not be disapointed. This stuff can be used in Manual transmissions that call for ATF, even though it's a manual transmission lubricant.

In my case it was like pouring in a brand new transmission. The shifts were unbeleiveably smoothe yet sturdy. I got a hold of one of the guys @ Redline and told him about my expierances with this product in my Explorer. I didn't know how long this stuff could last in the tranny before it needs to be changed so I made an inquiry about it. Apparently, it only needs to be changed every 50 000 miles... not because it will start to break down at this point, but because of the possibility of contaminate build up. It only takes 2 1/2 quarts to fill it to, so it's cheap insurance.