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GL4 gear oil

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Rut

Rut

Obi Wan
Offline
As many people have, I'm searching for some GL4 gear lube for my rear end. I have a 73 model 3.9 and don't know if it makes any difference vs the 4.2 that came in the car. Any suggestions or brand preference?
Thanks, Rut
 
Currently running a 4:55 gear, but use to run a 4:22. Really doesn't make any difference today being that the molecular bonding is way more sophisticated then what was offered when they printed owners manuals. Running high impact 58404 Redline synthetic 75-140 nice and smooth!! If your running a SLD, I would pick up some AC Delco LSD additive to add to GL4-GL5
 
We've got 3 parts stores in town here, but NAPA was the only one to have GL4 in stock. Can't remember the brand, but it has seemed to work just fine.
 
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