727-8 Reaction Shaft Differences

[pentastarpro]

What is the significance of additional ball (arrow) in reaction shaft housing? Shaft on right w/ 2 ball plugs (arrow) is from 74' BB motor home, left w/ 3 ball plugs is from 81' D100 lockup. Part numbers on housing are the same.

 

[Max1196]

Flip it over and compare the two, you'll see further differences that will be obvious that they're not interchangeable. Lockup unit is meant to be used specifically for a lockup setup.

 

[pentastarpro]

Thanks for your reply.
I had already checked everything with calipers & air but just rechecked again. All OD/ID measurements are the same and orifices are identical & clocked the same. The only difference, other than VB & input shaft, is the ball plugs. Both trans were pulled by me years ago & were operating as intended. No evidence of tampering.
I'm stumped.

 

[pentastarpro]

I also checked the main pump housings and they are identical in all features. ???

 

[oldkimmer]

I agree with Max1196. Kim

 

[pentastarpro]

Thanks for responses, was hoping to get more definitive info.
Differences btw input shafts & valve bodies are obvious, reaction shafts -- not so much.
I'm swapping non-lockup assembly into turbo nitrous /6 case that will be turning @ 8k shift points. I don't feel the lockup converter is going to like that even if I change to electronic control. The converter & VB will be unique for this application. Still chasing old speed trials goal of 1mph/ci (170mph). Best so far 154mph.