# Rear diff fluid change.



## Hoofer814 (Apr 11, 2020)

Hello everyone. Any fluid recommendations for the rear differential on a 66 Pontiac Tempest? It has a 300 transmission in it that was installed by the previous owner to mate up with the 455 engine he installed. And will i need the friction additive? Thanks!


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## GTOJUNIOR (Aug 7, 2011)

Diff additive is only needed if it's a factory Limited Slip/Posi Track rear.
455 with an ST300. Might want to start thinking about a new trans.

Cheers.


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## Baaad65 (Aug 29, 2019)

Strange Engeering recommends Lucas 85-140 conventional, that's what I used in my 12bolt and while you're at it install a magnetic fill plug, cheap insurance.


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