First off this is the second of two late model (26/27)trannies I have found the same issue. Inside the brake drum there are lugs that the large clutch plate rest and slid on as high/low pedal is applied. In both cases the large disk wear and tear into the lugs creating grooves and damage so deep the disk cannot disengage.
I also found all but two large disk cracked or broken in two. One ring pin to loose to stay in ring. The holes for the pins in the drive plate was wallowed out.
I was looking last night In Mac's for these steel caps I used to restore these lugs before. They still show them avalaible.
Hope this helps anyone.
Lightened up the photo a bit.
Yep, the replaceable hardened lug Part # 3312 is gone missing, that lead to the wear ding to capture the disc.
Some years ago there was a problem with new lug shoes, but now the best ones are hardened correctly and are supplied by Chaffins.
A side note, the design of the 3312 is for a 'clamp' fit, the inside of the lug having a dipped done finger to give a spring grip, the edges of the shoe are tapered in to match the taper groove in the cast iron lug platform.
Be sure the lug shoe is a very tight spring- press fit to keep it in place.
Maybe I misunderstand, but when you say you used the caps to restore the lugs in the past, you make me think that the lugs didn't have the caps to begin with and you only added them after seeing damage. If that's the case, then please be aware that those caps are not made to repair worn lugs, they are standard equipment and should have been there from the start. Installing them now, on the lugs you photographed, will do no good. I'm afraid that drum is toast.
If I did misunderstand your comments then please forgive my confusion.
No Jerry you did not misunderstand me. In fact you understood me correctly. However, It is I who is unaware that those steel cap were there from factory. Sorry for misleading you sir. Thank you for setting me straight.
I guess I can't figure out that in two trannys, I have yet to find one of these caps. The first tranny I installed these caps, the lugs were almost as bad and never had trouble with that tranny after installing them. So, I assumed the caps were a method of repair. My bad.
If you own a shop manual,it is in there.