This just happened yesterday. Has anyone ever seen this?

 

That's a new one on me.

 

dont think thats good....

 

Something forced against the band which forced against the servo to push it out far enough to break the housing.

Any more explanation such as recently rebuilt, high rpm neutral drop etc?

 

Nothing special, I have been driving it for about 700 miles with the new motor. I was actually taking it easy on it. I was on my way to work. I made it a half mile heard a pop and then a smoke show insued.

What could possibly force against the band besides the drum?

 

Ouch!!!!!!!
Looks like a new tranny on your Horizon......... Sorry to hear that. Especially after just paying for a new engine

 

I wouldn't think there would be any way for the band to have caused that. It would have to be from the oil pressure pressing back against the cap. The band is recessed in a pocket in the case(at least around the area that the servo pin is located). I assume this is a 700R4?
My guess is that it was something related to the line pressure or something wrong with the servo itself. Was that the Corvette servo, or one of those billet high dollar jobbers? Looks like the Vette servo from the pics.

 

looks like it had a neutral drop in its life. the new motor probably had enough torque to supply the pressure to break a hidden fracture.

 

First, a neutral drop will not do this. This is almost always caused by the snap ring not being fully seated in the groove. If there is a little dirt in the groove, then this can happen. It "must" be fully seated in the groove.

 

No disrespect intended, but neutral drops cause undue stress all over the transmission, so yes a neutral drop could have been what weakened this location, I've never seen an unsecured snapring cause a fracture. I've seen them go flying off the transmissions taking the servos with it, but never cause a fracture below the snapring groove.

 

Yes this is a 700r4 with the vette servo.

The ring was fully seated in the groove

I agree a nuetral drop won't cause this. I never did a nuetral drop.

I just picked up a burnt up 700 now I just need to swap the guts out.