1977 Pontiac Trans Am – Custom Stainless Exhaust Build & 4L80 Bellhousing Repair

In this episode, the ’77 Trans Am gets a full stainless‑steel exhaust system and the 4L80 transmission finally gets its cracked bellhousing repaired. Lots of fabrication, lots of welding, and a whole lot of problem‑solving. Here’s what gets done in this chapter: – The temporary glass packs are removed and the new stainless eBay mufflers are test‑fitted. – Both mid‑pipes are trimmed, miter‑cut, tacked, and welded to tuck tightly into the tunnel. – Custom exhaust hangers are fabricated using Allen bolts, washers, and flat bar, then welded to the pipes. – Both sides are removed, fully welded, smoothed, painted, and reinstalled. – A new spool gun is tested for aluminum welding, and a donor bellhousing section is cut from an old transmission core. – The 4L80 is bolted to an LS block for alignment, the patch is beveled, strapped, and welded into place. – Welds are cleaned up inside and out, showing solid penetration and a strong repair. – The transmission is prepped for paint, new gaskets, and missing parts like the tail shaft and speed sensor. – Exhaust tailpipes are finished with angled dumps and final hangers, then bolted in for a test run. – The Trans Am fires up with its new stainless system — louder than expected, but with a deep, throaty tone. Another big step forward for the Trans Am and the LS/4L80 swap. Thanks for watching, and we’ll see you next time.