There is a lot of metallurgy in those sprags. It’s not just the heat treat, it’s the case hardening and the metal they are made from that’s the biggest concern. You can have a sprag with the right heat treat, but if it’s not case hardened and “tempered” correctly it will be to brittle. It needs to be hard where the rollers ride, but soft enough in the center to allow the part to flex instead of cracking. I hesitate to even suggest aftermarket replacements because there is some really poor quality parts being made.
I built a 350 for a friend, the trans went into a mild small block Camaro. The bought the sprag and overhaul kit from eBay, it didn’t last 3 weeks before it exploded. Tore up the pump, obviously the direct drum, and lots of shrapnel. The stock drum a and stock sprag race I reinstalled are still going last I heard.
Same thing with the 4L60/4L60E aftermarket 5 pinion carriers. You need to buy that kind of stuff from a reputable place. The money saved buying junk won’t go far having to fix the damage.
This is an area i would love to learn more about.
Obviously i am a machinist, as ive said, namely a tool and die maker, not so much just an operator, so i obviously have an understanding of metallurgy.
As you probably know, I'm not a noobie when it comes to transmissions, ive been fiddling with them for maybe 2 years now.
Not an expert, neither do i know rverything.
BUT, what i wanna learn is, the middle ground between the metallurgy and the parts themselves.
As in- what can be hard, what must be case hardened, what needs to be soft, and all thr why's to follow.
I know that **** inside except actual roller bearings and sprauge elements can't just be 58 rockwell hard, but when someone says, "i kept twisting off output shafts, so i installed a hardened one".. i know they dont mean my version of hard, like 60 RC, tool quality. What does that mean exactly?
I understand what billet, cast, etc all means obviously, just not so much in terms of what "hard" is for high performance applications, and their molecular properties.
I assume it to be like, 4140 steel, thats been heat treated, so it still twists slightly, but it doesnt wear out or break off.
Alot if people just like throwing out big words they otherwise dont even understand, like "chromoly" for example. Its more if a bragging right amongst circles to say you have..... "chromoloy axle shafts in muh rear end"
I hate general lore and internet mechanics when it comes to transmissions, or rear ends, or whatever.
its like, when someone says "well those arent worth a damn, because my buddy that knows a guy blew one up one time", that screams to me, i dont understand this, so im going to immediately shoot it down.
It costed me two 700r4s with an improper TV cable adjustment when i was younger to learn why people in general despise the units. 1 guy didnt set his right, so he tells his buddies "all" 700r4s are junk.
Ive taken them and the 4L60e apart enough to know weaknesses, and know why the generic end user hates them, they have flaws in stock form, so they get a bad rep from everyone that doesnt know how to upgrade them because its not "plug and play"
- you get the point..i also understand there is physical limitations to all these various units before you must move to the next step in a unit (i.e. th350 to a th400)
The issue i keep running into, is, when i discuss this with far more experienced builders that possess more than 20 IQ points, they can never give a solid answer on the metallurgy, just the why, obviously because they are not equipt witt that knowledge
The "whys' i already know, or im learning as i go.
Maybe sometime you could have a telephone call with me, and maybe explain some of this?
Its just purely for my personal knowledge.
