OK, so I've never rebuilt a transmission before, so I'm rebuilding mine..and I thought it might be cool to take lots of pics and share cuz it might be helpful! I know there are a few threads out there on this already bit thought it may still be useful to get a rookies perspective and I have lots of reference pics to may help someone (including me lol) remember where stuff goes! So....here we go!

EDIT: side note: the transmission being rebuilt is a aluminum case OD in a truck.

Shifter assembly and rod/levers removed..they are oriented how they mount on the side cover

Close up of levers...some number stampings are visible

Shift rods and small parts

Scrubbed, cleaned, and repainted:
Levers

Rods

Here is one I thought could be super useful..side cover bolts in position where they go. Should be able to see in the pic the one bolt with the taller shoulder, and the two thinner longer bolts at the bottom

well,what happened?i was lookin forward to this.ya didnt get scared once ya got that cover off ,did ya

Thank you! (This is why i love this board!) Clarification here: levers when installed should look something like this:

OK, once I got the transmission on the bench, I took the side cover off. For reference:

OK..the countershaft. First thing I did was remove the 6 bolts for the tailshaft. You then can rotate the tail shaft and use one of the bolt to hold it in place and you now have access for the other counter shaft bore. Apparently aluminum OD cases are "blessed" with a loose fit counter shaft, and a plug that seals the opening...what I did was drill a hole in the plug, and used a brass drift to gently push the shaft through the other side. A woodruff key will fall out. With the shaft out, let the countershaft gear cluster sit at the bottom of the case.
From the manual, rotating the tailhousing:

The plug (with hole drilled):

The bore the plug was installed in:

The opposing bore (note the notch where woodruff key sits):

P.S. you pros out there...if I'm doing something incorrect, for the love of God please stop me and say "Hey stupid! Your doin it wrong!" Lol

Next, I simply removed the bolt from the tail housing, rotated it back down, and with a few taps with a rubber mallet, worked it back and out.
Tada:

Next I removed the four bearing retainer bolt from the front of the case, slid the retainer off, and with my trusty rubber mallet gave a couple love taps and the main drive pinion and bearing come out the front of the case
Retainer removed:

And out she comes:

And here you can see the rollers (I'm quite amazed they didn't fall out lol):

With the main shaft and drive pinion out of the way, now its time for the countershaft gear cluster..I simply worked through the rear of the case....with it came rollers (I counted 76), 4 spacers rings, two thrust washers, and a spacer shaft
Gear cluster out:

Exploded manual view:
52, 49- rollers
53, 48- spacer rings
54, 47- thrust washers
50- spacer shaft
51- gear cluster
46- countershaft
45- woodruff key

Next item on the menu is the reverse idler gear...I removed the reverse switch..oh, and I almost forgot; when you pull, the side cover, there is a spring and ball which serves to position the reverse lever..don't lose that! I will get a pic of that tonight and where/how it is located. Anyways, so the manual shows a nice fancy tool to remove the reverse gear shaft...I made my own ghetto version lol. I didn't waste time making it pretty, I just wanted the shaft out! So using my ghetto tool I pressed, the shaft out the back of the case
The manual:

My ghetto variation of the tool:

And shaft and gear out of the case:

Alright...tailshaft...first, remove the speedo pinion. Then, if look in the pic, you can see the tangs of a snap ring between the tailshaft housing and that last gear (1st speed gear I believe). This varies on some transmissions, but on this one, the snap ring has to be EXPANDED to release the main shaft assembly. Doing this by myself was tricky..in one hand, pliers to expand the snap ring, in the other my trusty rubber mallet to tap the shaft forward. Once I got past the snap ring groove it was gravy.

Mainshaft assembly out (those pros with a keen eye may observe that the 3rd/OD syncro assembly is removed...I'll return to that later)

Looks good so far, post up a picture of the cluster gear pin .

To further disassemble the tailshaft for cleaning and prep it for the rebuild, I removed the rear oil seal and mainshaft yoke bushing...I just used a punched and hammered thebushing in till it fell out...not sure if there is a "right" way to do that?
Bushing after forceful removal:

Tailshaft minus seal and bushing:

Tailshaft cleaned:

And tailshaft all pretty and painted: