My first transmission was an early 700r4 in my c4 vette.
That's just a 4l60 with a mechanical valve body and a computer controlled over drive/converter lockup.
It wasn't bad, i bought a how to dvd off of ebay, converted it to a file ao i could watch it on a tablet computer.
I also had the factory service manual as a general reference.
My first attempt worked great, but i had the pump rotor explode on me after like 4 or 5 thousand miles.
I used a no name pump rotor that came from the kit.
And i had my pressures boosted for some F1 quality quick shifts...
That took out the pump housing.
Replaced it with a later model pump that i had to setup the fluid pathways for my earlier transmissions.
That i had to use the factory service manual and the original pump to figure out.
It got a billet pump rotor and a looser/higher quality converter with the second go around.
I also didn't need the video the second go around, but my 84 factory service manual had a typo, the forward sprag had the freewheel examples arrows pointing the wrong way!
Man the transmission does some weird shit when the sprag is in there backwards!
I saw in someone elses 86 manual, the arrow was pointing in the other direction... lol
The earlier "lip seals" are stupid, what a pain in the ass.
I upgraded everything as i had more info, and the hard parts are all upgradeable.
I love gm for that kind of mindset.
I ended up replacing everything except for the case, valve body, and the input drum with the later stuff.
Shimmed endplay to perfection, and reinforced the input shaft/drum.
It has been going well ever since.
Lessons from that
Earlier shit shimmed.
Like converter spacing.
Watch out for falling washers, catalog everything.
Air test everything, use transmission assembly lube/gel, don't get shy with it.
The blue stuff worked great in the summer and winter.
And about a year or two ago i did a 6l80 from my tahoe.
Upgraded everything that needed it, focusing in boat hauling.
Absolutely wonderful transmission.
Documentation wasn't great, selectives for clutches are not available, they use selective snap rings instead.
Better stuff available now, anoying!
I got mine pretty much perfect, parts cost alot more than the 4l60.
I learned don't touch the converter lockup in the tune unless you really understand it.
New info just came out about it this year, like reducing allowed slippage also raises the lockup pressures.
And an aftermarket converter like mine with more than one clutch can put lots of hydraulic pressure on the thrust bearing if you don't also reduce lockup clutch pressures...
Fun stuff overall, but I'm a dork like that.