Author Topic: 12 bolt diff fluid  (Read 2527 times)

hrlyfxdl

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12 bolt diff fluid
« on: October 03, 2016, 08:46:31 PM »
Hey, I tried searching the strings on here and couldn't find this posted before. I am replacing the gasket and cover on my 68 Camaro, and wondering what people recommend for the replacement fluid? It's a 12 bolt posi rearend. It's not stock, it's a 3.73 in there, supposed to be a 3.31. I have some Royal Purple 75w90, and states it doesn't damage any yellow metal parts. Anyway, what would you recommend as a new fluid with todays technology in fluids, and how full? Thanks.
1968 Camaro SS 350 8L34677?
07A  E107  TR 712  U-U

5hane

ko-lek-tor

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Re: 12 bolt diff fluid
« Reply #1 on: October 03, 2016, 08:49:05 PM »
http://www.camaros.org/forum/index.php?topic=566.msg3107#msg3107

Royal Purple eh? Sounds like they are trying to re-invent the wheel? If it smells bad, it is good to use. Why, because that is sulfur added to provide lube. I don't recommend synthetics. all oils have a SAE rating somewhere on the package. I am sure that stuff you have will work ok. You will need an additive for the posi clutch packs to prevent chatter. Used to be Sperm Whale oil. I am sure it is something else. Used to get it at the dealer, back when this country was...ah, don't go there Bent. I'm sure you can find it at a well known chain auto store.
Bentley to friends :1969 SS/RS 396 owned 79
1969 SS 350 (sold)
1969 D.H.COPO replica 4spd. owned since 85
1967 302 4 spd 5.13

Mike S

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Re: 12 bolt diff fluid
« Reply #2 on: October 03, 2016, 09:21:03 PM »
 I was faced with the same decisions when I refilled my 12 bolt posi. I went with AC Delco GL4 fluid (I think it was 75W90) and AC Delco 10-4003 posi additive.

Mike
67 04B LOS SS/RS L35 Hardtop - Original w/UOIT
67 05B NOR SS/RS L35 Convertible - Restored

hrlyfxdl

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Re: 12 bolt diff fluid
« Reply #3 on: October 04, 2016, 02:44:02 PM »
Thanks guys, appreciate the input. I went and got some fluid last night based on the postings and prior string. Much appreciated. I dare say, this is one of the few GOOD places on the internet.
1968 Camaro SS 350 8L34677?
07A  E107  TR 712  U-U

5hane