[MagicRat]

Hi.
I had exactly the same thoughts last summer. The 700R4 on my van broke an annulus (ring) gear with a bang. I removed the transmission, got a service manual (Haynes makes a good one for step-by-step rebuilding, with photos) and proceeded to disassemble the transmission.

Now, I have done extensive automotive work over the years, including rebuilding engines and manual transmissions. IMO the automatic transmission is by far the most mechanically complex thing in your truck and rebuilding it is tricky, even for an experienced mechanic.

There are hundreds of components that must be precisely reassembled in exactly the same way they came out. It is very easy to misplace a component or not install it properly, which will affect operation.... but you may not realise this until you take the effort to reinstall the tramsnission, fill it up and test-drive it. For example, the valve body has many ball-bearings that act as flow valves. When reassembling the valve body the RIGHT and WRONG location for these ball bearings look practically identical. If you lose track of them, the transmission will not work right, and you will have to drain the transmission and disassemble the valve body again to figure out why.

Other concerns...... my manual indicated that the stack of clutch disks that were removed must be reassembled in exactly the same order they came out.... but they all looked identical to me, another example of the precision and organization needed.

If you have lots of time, patience, and a clean, well lit and organized workspace, rebuilding the trans is, IMO a 4 out of 5. You WILL need specialized circlip pliers, a special spring compressor tool and an air compressor. You need LOTS of little containers and baggies to keep track of all the little parts and their location. I also suggest to use the Haynes rebuild manual for GM transmissions. It is easier that replaying a video 10 times to figure out a particular step. But the videos are also essential, too.

When I disassembled my transmission, I found the broken ring gear has also crunched a planetary gearset and a couple of other parts. Replacement parts were a fair amount of money. I ended up locating a used, recently-rebuilt 4L60 for $150 which I swapped in. It was, in the end, much cheaper and easier that rebuilding my existing unit. It is also a better, stronger unit that my 1983 700R4 trans.