We spent a lot of time breathing new life into the 143000+ mile 1989 Spirit ES only to discover the left axle seal was leaking. Changed the seal and resealed the bearing retainer a few times, changed the axle too but the leak continued. Research showed the likely cause is worn diff bearings.
Google helped me find information on this Axle stabilizer made by Teckpak: https://www.transmissionpartsusa.com...-032125lrb.htm
I spoke with a rep there and found out that this has been on the market since the 1990's. He was surprised to hear there was still a car on the road that would need one. I was surprised that I didn't find it on the forum. With nothing to lose, one was ordered and installed.
No more leak!
It doesn't have to last forever, there's a fresh 568 in this car's future.