Material of tranny internals.

[BlackonBlack89]

What type metal is the tranny made of?? specifaclly the gears sets (or 3rd gear). I am looking into a process called Ion nitriding (plasma nitridng) to maybe solve/extend the life of the tranny. Maybe comboing it with shimming the trans for better results? I called a place and explained what I needed done but he needs the type of material for a price quote. And I didn't know exactly what it is, so here I am. I am going to call back and talk to the guy about the other processes (cryo'd and shot peening) and see if this process has any better charactersics. As some others have said it does not hold up that much longer/still can fail.

I really want to see if this can atleast make a SHO tranny last without spending 6.5k. Even though I dont think I will ever make much more than 350WTQ. I want to have a reliable boosted SHO. As I do not want to swap trannies ever so often.

And related Q. Does anyone think it could work on axles too??? Just wondering as after the tranny the axles are next in my book. or I am going to have to start saving for some stageV axles.

 

[rocket455]

i tried to look it up and find out for you, but i found nothing. if i had a gear in hand, i could find out for you by saturday, but unfortunatly i do not

but heres a cool piece of info i found:
"The MTX-IV is a beefed-up version built by Mazda and introduced in 1989 for the Taurus SHO. It was also used in Tempo/Topaz models equipped with the Vulcan V6."

 

[gmorrell]

It's likely near impossible to know exactly what Mazda used in the MTX-IV, but it would probably be safe to say that it's very similar to SAE 8620, which is a common medium-carbon chrome/moly/nickel steel alloy that is hardened and carburized, or case-hardened, after machining. 8620 or similar is frequently used for gears and shafts in automotive applications.

Nitriding typically works best with steels containing some Aluminum, about 1%, but 8600 series steels seem to respond well to nitriding, despite the fact that 86XX has damn little Aluminum.

Nitriding will no doubt increase the surface hardness of the gears, but won't have much, if any, effect on shaft fatigue strength.

 

[St Louis SHO]

The axle thing, no. It just blows up the CV part in most cases. Spares are cheap

 

[Mr. Chad A.Meirose]

I've rebuilt my tranny.. the gears seemed like regular old hardened steel gears to me...

 

[LOUDSHO92]

It wont help much for the strength, just the wear. We use similar processes on some products and tools and thats whats there for, wear protection.

 

[redwraith94]

The nitriding will make the steel harder, and more brittle. So if you are worried about the gear teeth cracking / sheering off I don't think it will help there unfortunately.

There is a company out of Texas that has a proprietary Electrolytic Iron bath that supposedly is about 95,000 psi tensile strength, and around 225 Brinell. It is called the Van Der Horst bath, and is proprietary. I was thinking that either this, or possibly Chrome plating could be used to heal surface cracks, but I have no evidence of that from anyone else.

Hey rocket455 if you can find out what alloy, and or heat treating process was used I have spare tranny internals that I would be more than happy to send out to you. Can you pm me your address? I am very interested to know the exact alloy too.

 

[hawkeye18]

"The MTX-IV is a beefed-up version built by Mazda and introduced in 1989 for the Taurus SHO. It was also used in Tempo/Topaz models equipped with the Vulcan V6."

Yeah... beefed up from being able to handle 100lb/ft to being able to handle 150lb/ft.

Sorry, I'm an ass, etc. etc. I know.

 

[92sho16]

....Chrome plating......

You do realize that when something gets chrome plated it gets dipped in acid and becomes weaker.

 

[redwraith94]

One way of preparing a part for Chrome plating is an acid etch, and hydrogen embrittlement is a concern. Hydrogen can be 'baked out' though, it just takes longer to process, and you have to be careful.

 

[BlackonBlack89]

It's likely near impossible to know exactly what Mazda used in the MTX-IV, but it would probably be safe to say that it's very similar to SAE 8620, which is a common medium-carbon chrome/moly/nickel steel alloy that is hardened and carburized, or case-hardened, after machining. 8620 or similar is frequently used for gears and shafts in automotive applications.

Nitriding typically works best with steels containing some Aluminum, about 1%, but 8600 series steels seem to respond well to nitriding, despite the fact that 86XX has damn little Aluminum.

Nitriding will no doubt increase the surface hardness of the gears, but won't have much, if any, effect on shaft fatigue strength.

So in the never ending cycle to keep spending money on this car what would be the best answer to atleast lessen the possiblty of this weakness occuring. If hardening the gears does not help is there something else that could be done. (besides the gearsets) I would if I could

Could the third gear shaft peice be machined out of a stronger material. Basically copy the peice now but use a stronger material. Or would that cause 1 of the 2 meshing gears to wear done because one is a stronger material. I know crazy but I was just thinking randomly about this today. I am going to go search for some threads about this now propably all deleted though......

 

[redwraith94]

A tougher steel, or maybe just better heat treating process would help. Before the forum's crash a member mentioned that out of 20 gears I think most of them had microcracks. He had said they were New Old Stock. I don't know the extent of the cracks.

I know one way of checking for cracks is called magnetic particle testing, I have never done this though, and I don't know much about the specifics of the process.

Making the shaft would really be a pain though, the gear teeth have to be held very close, and it is a very labor intensive setup. It is well beyond my ability, but the people who can do it aren't cheap.

I think if we can find a way to 'heal' any surface cracks, cryo treat the shafts, and gears to remove as much residual stress as possible, and then shot peen to give it a uniform surface compression that would probably be the best we could do for a *reasonible* price. 5 grand for quaife internals isn't unreasonable, but I can't afford it either.