[RG]

After buying several wrong gaskets from the Auto parts stores because the number listed is incorrect, here is the text from Felpro:
“ran your vin number through our GM parts computer, it asked me to choose between a SSR or Trailblazer, after choosing the SSR it informed me that it had no RPO code definitions, so I looked up the rear differential and it offer two gasket numbers, these numbers interchange to Fel-Pro part numbers RDS55479 & RDS55387, the RDS55387 has 14 bolt holes & the RDS55387 has 10 bolt holes, please see the attached pictures, so you can match it up to your cover.”
Mike in AZ recommends re-using the original gasket which is rubber coated metal.
Mine was beyond re-use. The solution was to go a a Differential Specialist with
the Simple Engineering Cover with Amsoil for the scheduled maintenance

 

[Mike in AZ]

I actually like the GM parts..... They are a metal substrate with a silicone sealing bead on each side. Normally, very re-useable......

OEM part numbers:

Automatic Trans / Torsen differential = 12479379, about $20

Manual Trans / Eaton differential = 26063649, about $9

Hope this helps,

Mike

 

[RG]

Mike,
Could you post the numbers for the Transmission Pan?
I used the AC/Delco Kit and the gasket was too thin.
It leaked. So, I had to do everything twice.
I replaced it with your Transmission Cover at the Transmission Shop
with the heavier gasket.
Worked great also.

 

[Mike in AZ]

Mike,
Could you post the numbers for the Transmission Pan?
.

The OEM seal for the tranny pan is also metal substrate with silicone bead seal on both sides. Fits LOTS of stuff.......

GM auto tranny seal 8654799 About $6

Regards,

Mike