Red Eagles are the same as they always been. Cellulose base saturated with a hard resin then a silicate.
My theory is.....They wanted a friction that was easier on the Nitrate Treated Steel plates while having a very short lock-up time (higher coefficient of friction) This is a very delicate balancing act but Alto did a decent job considering they were developed 30+ years ago when High Energy Carbon technology was in it's infancy & was pretty well locked down by patents.
In the case of 4L60E's.....The 3-4 clutch piston is to small to effectively use the frictional properties of the Red's (Not enough clamping force), This led to a substantial INCREASE in clutch pack temperatures. Standard Cellulose (700R4) frictions lasted longer! And of coarse High Energy was a BIG leap forward.
Another interesting theory.....Red Eagle's "hold" very little ATF in the friction matrix which I'm sure is a result of the Resin Saturation process. Standard Cellulose & High Energy frictions "hold" a lot more ATF.
I soaked all 3 types in ATF & allowed them to drip-dry, Compared before(dry) & after(wet) weight readings to come to this conclusion.
*The ATF in the friction material acts as a heat-sink to the friction surface. But this creates surface tension between the friction & steel, As a result.....The friction will skid/slip across the steel 'til the the tension is broken.
**IF Clamping Force is great enough & Actuation is quick enough for the oncoming clutch......Red Eagle's are a decent material choice. The reason they are so popular in purpose built Drag Racing transmissions.
Surface Tension with High Energy Carbon friction material can be remedied by employing Surface/Face Grooving.....Giving the ATF paths of escape. This the BEST combination of holding power & longevity when it comes to Highly Stressed Dynamic clutch packs.
Do some research......You will find that Surface Grooved High Energy Carbon frictions are being utilized more & more in high performance applications!