UH-OH!! Tranny kicked down and GRIND/5000RPM - 2nd gear's toast

[Clead]

On the way home an hour ago in the '83 5th Ave with an A904, I gunned it to pass someone, I heard a clank, then a grind as the rpms climbed with no load. Got out, looked for tranny pieces on the road, and saw none. I managed to crawl home in 1st gear without incident, so I'm pretty sure the rear-end is ok. If I let it try to shift into 2nd, it has serious problems, but 1st is fine. Now the big question: What happened? (If you can tell from my description)
Big question #2: How hard is it to do a re&re on a tranny? I have the A999 still in my DipCop parts car that I wanted to swap in eventually anyway. How much work is involved if I do this myself? I have done a few rad-swaps, carb-swaps and brake-jobs. That is the extent of my mechanical experience. I have a floor jack, jack-stands, FSM, full tool set etc. Are there any specialty tools required?
Thanks for any help you can offer.

[skankweirdall]

Do you still have reverse? You didn't give awhole lot of info there but generally loud clatering, clanging, or grinding noises mean something mechanical is broke, like a planetary, sun, or annulus gear. If you leave the shifter in drive will the car take off in first gear or do you have to manually pull the shifter in first before it will move? If that's the case then the overruning clutch is toast.

Well it sounds like you'll be able to add tranny swap to your resume. Just have a buddy help you, if for nothing else than to help stablize the tranny on the jack. You don't want that thing falling on you or your hands or arms. They can cut you bad.

[6 packin]

If he dont have reverse the more than 2 gears is lost. Drive3 and reverse is in the same drum. Check the fluid level, see if its a brown shade in stead of red. If so I suspect your clutches are fried.

[Clead]

Ok sorry for the sparse info guys. I do have reverse, and it seems ok, but the there is a little grind when I put it into R. The car doesn't take off very well in D but it will, until it tries to shift into 2nd. When I put it into 1, it drove fine. No grinds or unusual feel at all. The fluid was a nice ruby red color, too. So... does that clarify things?
Thanks for the replies guys.

[skankweirdall]

Yep, the over running clutch is toast. The only difference between 1st gear with shifter in D and 1st gear with shifter in 1 is the rear drum band is applied. That's why I asked about reverse as well. The overrunning clutch holds the rear drum in 1st D. The overrunning cutch overruns in 2nd. If the clutch is locked up (that's why it still moves in 1st D) it will make all kinds of racket when the trans shifts to 2nd. The fact that it makes no noise when in 1st 1, but does when in 1st D, indicates the overrunning clutch.