727, sprag inner race grinding in housing

[mhinders]

My 727 was in a sorry state when I disassembled it, and it had at some point been incorrectly assembled, for instance the thrust washer was missing between the input and output shafts.

In the enclosed pic you can see how the inner race of the sprag has been grinding in the housing.
I'm not sure what's causing this? What is it that locks the output shaft in a certain position...the output shaft ball bearing, or something else?
What would be the best way to correct this?   

[John_Kunkel]

Sonnax makes a case saver but by the time you pay for the part and the machining you're probably better off just looking for a replacement case.

http://www.sonnax.com/product-lines/transmission/parts/1674

[mhinders]

Thanks for the info John.

I had hoped for an easier and less costly way to solve it...is it the ball bearing with its 2 snap rings that set the position of the output shaft? 

If that's the case maybe I could improve matters by making sure that the inner race bottoms out on the shaft and not on the case? Could maybe be achieved by shaving off material from the extension housing to the case sealing surface?

[John_Kunkel]

The sprag inner race is pressed onto the rear band drum which is free to float forward/aft on the rear support. I don't know why some races dig into the case and others don't. One trick I always employ when assembling a trans is to drill a small hole (.060") in the case where the inner race rides, this hole connects to the lube fluid as it enters the case from the cooler.

[John_Kunkel]

Lube hole viewed from the rear.

[mhinders]

Yes, thanks John for your comments, I wasn't thinking straight when I wrote the idea about the output shaft (guess it was wishful thinking... I realized the following morning that both the drum and the inner race are free floating, and the output shaft wasn't a solution.

My inner race is actually free floating on the low&reverse drum, which in turn is free floating towards the rear end of the case...think I read somewhere that it wasn't until 1991 something when they changed the design and started pressing the inner race to the drum?

Interesting idea with the lubricating hole! The case you are showing is very nice compared to mine ...

I attach 2 pics. Strangely enough the steel parts have suffered too while grinding on soft aluminum...the only explanation I can think of is steel fragments in the oil acting like a grinding paste, grinding more in the aluminum but also in the hard steel!!??

[mhinders]

Sonnax makes a case saver but by the time you pay for the part and the machining you're probably better off just looking for a replacement case.
http://www.sonnax.com/product-lines/transmission/parts/1674

Thanks John for all help. I have this kit heading my way! 
Martin