Gear ratio on a posi
October 24th, 2018, 08:52 AM
#1
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Location: Pulaski Wisconsin
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Gear ratio on a posi
I obviously own an 84 Oldsmobile Delta 88, it’s got a 307 with a 4 speed auto, and a posi rear end. I was attempting to do some research but I guess my car isn’t really common or something, so I couldn’t find anything in the rear differential gear ratio. I found the transmission ratios but no differential ratios. Any help would help me
October 24th, 2018, 09:34 AM
#3
CH3NO2 LEARN IT BURN IT
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Location: Land of Taxes
Posts: 4,820
Count the number of tire revolutions to drive shaft revolutions. That will get you in the ball park. Pull the cover and look at the ratio stamped into the ring gear. Probably could use a rear gear service any how. Likely a high 2 or low 3 series.
November 18th, 2018, 04:42 AM
#4
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Location: Leominster, Massachusetts
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According to the 1984 Dealer album, 2.73's were the standard gear set for the Delta 88 with the 307 V8 and 4-speed overdrive transmission. 3.08's and 3.23's were optional (with the HD cooling) except in California. High altitude cars got 3.23's standard. As Fun71 said, there should be an RPO sticker (most likely in the trunk on the lid) with all of the codes on it.
GU2 = 2.73
GU4 = 3.08
GU5 = 3.23
G80 = limited slip (posi)
GU2 = 2.73
GU4 = 3.08
GU5 = 3.23
G80 = limited slip (posi)
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