don't let extech fool you - this is not his first rodeo.
i rebuilt a c6 once. (there's some good videos out there by a guy who goes by "BadShoe").
when i was done, i had a piece left over. don't know where it was supposed to go.
not taking it back apart to find out.
i hope to never be inside another auto transmission...
I rebuilt a 4r70w in my 1999 GT Mustang. I watched a lot of videos and still messed up my pressure regulator valve. I used to be a lot better mechanic when I could see things. Ultimately got it done and it worked,
one of the important things is to have the right stand so you can rotate the case at different points of assembly. Gravity - no better friend, no worse enemy!
I don't know why you'd want to rebuilt a out dated trans. go with either the AOD or
the 4r70w. The later needs a stand alone computer about $800 but the AOD is a bolt on.
same 6 bolt small pattern.
I'vwe rebuilt two C4 trannies, it's really simple as long as you have a nice long work bench, long thin screwdrivers, 90 degree angle scribe, and a good det of snap ring pliers.
I used the Pioneer rebuild kit, no left over parts, that was 12 years ago and the tranny is still working like brand new.
The long bench is to lay all the pieces out in order from beginning to end and that way the parts go back in order. Some earlier C4 transmissions have less clutches so you may end up with an extra, but the rest is a simple clean replace and snap back together.
Don't overtorque the pump housing bolts because they will strip and sometimes crack the housing and cause a leak. I highly recommend a thin coat of permatex non hardening thread sealer for those bolt threads, it equalizes the torque accurately and prevents leaks through the bolts.
With no transmission experience, I rebuilt a C4 back in the 80's using a couple of articles from car magazines as a guide. Plus One on the long table and a good set of snap ring pliers. Take your time and take pictures as you go. I haven't looked for youtube videos, but I'm sure good ones are out there. I've read good things about both Pioneer and TransTech.
This will date me - late 60s early 70 used B&M Transkits to do a few.. Great instructions and the benefit of variable stages of performance. 8 years ago beefing my 76 Bronco for SW desert and rock climbing B&M Transpack was simple for the C4. I added the TBE
deep girdle pan. Person I sold it to two years ago went back to stock valve body because he didn't like 2nd gear rubber most of the time. He is a 95% street driver.