The last melted diff that I worked on I was able to salvage the bevel gear, diff balls, thrust "bearing" and diff screw. I simply bought another set of plastic outdrives and a diff rebuild kit which was less that $15.
Here are links on AE's website for the instructions on how to build a TC3/TC4 diff.
Plastic Diff instructions (molded outdrives) - (http://aedownloads.com/downloads/ins..._outdrives.PDF
Steel Diff instructions (http://aedownloads.com/pdf/3918_inst.pdf
A few more ideas.
- You can use the TC4 steel diffs in the TC3 without any issue.
- If you decide you want to run a spool, you can use the TC5 slipper spool pads (in place of diff rings/balls) and create your own spool.
- And finally, you can order some of the hard to find parts for the TC3/TC4 directly from AE's website. They have comparable pricing to websites such as Tower Hobbies.