I'm having a strange issue with my 727 race trans. The rear ring on the stator support is wearing on the side. The wear is always,towards the rear. It wears the groove, wider at the top towards the rear. The front ring and groove are always fine. Drum is smooth on the ring sealing area. The drum bushing appears good. Except for the #1,#2 thrust washers everything else is Torington. End play was .010". This started about 200 passes ago. First time I just replaced the rings. 2nd time the reaction shaft support was replaced also. It now has 85 passes on it. Runs A&A wide bushing aluminum drum so it can't run Teflon. The high clutches don't appear to slip when this happens. They have 420 passes on them. Just was apart for a rotine look. Lots of steel from this issue on the magnet. Any ideas?
Thanks Doug

What is your line pressure? I was warned by Rick about that when I told him how high I was running my line pressure. I could see those rings being forced outward from pressure. The forward groove most likely gets more splash lube to the groove preventing the forward ring wear.
Also may want to check the fit of a new ring inside of the drum on the work bench. Be sure the bore isn’t undersized causing ring butting.
Not a trans pro, just my 2 cents.

I talked to Rick today. Turbo action VB pressure is pretty low. He told me they polish the stator support lands with 240/320. I will check the drum bore. But the front ring never does this. Good Idea though.
Doug

Doug, are you using black or silver rings? I've never seen wear like that, as I always use black rings on narrow bushing reaction shafts and silver on wide.

The drum is wide bushing, so yes the silver rings. The ultimate fix would be to sleeve the drum bore and use Teflon rings. Not sure what to sleeve it with.
Doug

Hard coat anodizing?

Not wearing aluminum, wearing the steel support.
Doug

you need to check your bushings in the stator and the drum for wear, and the alignment of the bellhousing to the crankshaft centerline. I have seen converters out of balance cause this as well. The input shaft goes into the converter if it develops a run out issue it will make the inputshaft force side loads on the bushings and drums, and the drums may even wobble at speed if the bushings are loose. You can take the empty case and bolt it on the block, attach a dial indicator to the crank and the tip on the pump seal area, rotate engine, no more than .003 runout allowed.

Might want to consider hard coating the drum then use the seal ring of choice.