[7t8ta]

In the process of re-doing the rear in my 78' TA putting in an Eaton Truetrac with 30 spline axles. Wondering what type of gear oil (weight & brand) do you guys recommend and how much goes in (fill capacity?) any recommendations are welcome. Thanks, John

[7t8ta]

Anyone? Please

[2manyT/A'S]

In the "old days"...we'd use the GM oil from the dealer & they had that special additive that was reccomended......Not sure if they still sell that kinda stuff there anymore...

[78w72]

80w90, i prefer valvoline, but any brand will do that meet the gl-4 or gl-5 specs for limited slip rear ends. if its a posi then check with eaton for what additive they suggest, i just did a 30 spline eaton limited slip in my 72 10 bolt, they said the gm additive was perfect. or any other that meets the gm spec.

fill capacity is 4.25 pints. 2 qts of oil & the Gm additive is .25 pint.

[7t8ta]

Thanks 78w72 that's what I was looking for. Will be putting together this week. I appreciate the help. I'll pick up some gm additive.

[rexs73gto]

The 80-90 GL-4 or 5 will work but I'd use the 80-140 syntc from Valoline with any of the extra posi additive. GM not longer sells the same whale oil posi lube. as the lube they use to have was actual whale oil grease & whale oil has been outlawed for about 25 years. It was great stuff & it use to be able to find at swap meets for a while but it's been gone now for a long time. GM still sells a limited slip posi lube which is a little better then some of the lubes out there, & if it was me I'd use it along with the 80-140 syntc. rear end lube. The syntc. lube works better in the rear ends because it will almost stop all the chatter from the rear when you go around the corner. It alo makes the rear posi grab a bit better & makes them run cooler.