Differential Fluid Change / 79 Vette
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Intermediate
Joined: Jul 2009
Posts: 25
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From: Knoxville Tennessee
Differential Fluid Change / 79 Vette
I have a 79 vette and need to change the differential fluid. I'm hearing some chatter when I turn sharp curves. Got a few questions (I know this has probably been covered here, so sorry for the repeat if it has):
1. Whats the best fluid to use at the best price? Is the Royal Purple a good choice ?
2. Should I add the GM additive ?
3. Where is the drain and filler plug? Are they hard to get to ?
Thanks !!!!!!!
Phil
1. Whats the best fluid to use at the best price? Is the Royal Purple a good choice ?
2. Should I add the GM additive ?
3. Where is the drain and filler plug? Are they hard to get to ?
Thanks !!!!!!!
Phil
Le Mans Master
Joined: Aug 2006
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From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
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There is NO drain plug! You have to siphon out the old gear lube, then ad one 4 oz bottle of posi lube that you get from the Chevy dealer. Then top up the differential to the bottom of the fill hole. The book calls for SAE 90 GL-5 gear lubricant but 90-135 worked for me. ( Any brand is fine.)Then make some slow figure 8's and see if that helps. If that doesn't help try a second bottle of additive. If that doesn't work it's time for a rebuild or just live with it.PG.
Last edited by Peterbuilt; Jul 14, 2009 at 07:11 PM.
