I'm not 100% sure about the rear sprag. I've done some research, but haven't found any definitive info. I did read that without it, the front drum could spins, something along the lines of 5 times faster than the engine RPM. For "us" and the CTD, it my not be as big of a concern, but even 15k RPM inside of these transmissions doesn't sound good. I was hoping someone would pop in and talk about it a little.
On my 727, the output shaft support is worn and the aluminum is galled in such a way that it almost looks as though IF there was enough wear on the rear sprag, I could see the rear drum causing the galling.
Tough to see in the pic, but it is not in great shape. I did find a replacement. No idea how long it been this way.
Maybe too much play in the rollers and springs? I'm not sure, but my TF727 book does say that any wear on the rollers and springs should be reason to replace the components. Mine didn't LOOK terrible, but that would be tough to tell.
The rest of my trans didn't look to be in bad shape. It was just slipping fairly bad and there was a vibration when accelerating. I originally thought that it might be driveshafts, but the vibe happened at lower RPM's and now that I've seen what I have, I suspect that this might be, at least, SOME of the trouble. Maybe not, but the output shaft support is not right.
I'd bet that your friend would be VERY aware of these issues and take care of them, but for someone taking a trans to a local shop, I'd wonder how many builders pay attention to this. My $.02.
Thanks!
Andrew
1991 W-250, auto w/ O.D. 134k. Intercooled. 16cm exhaust housing. 3k gov spring. Little more fuel, little bit of timing...