Quote:
Originally Posted by Hog
The loading of the engine also contributes to exhaust noise, which would be reduced with a lower gear, not rpm/speed alone.
But 3.54 to 3.45 no human ears would be able to tell the difference. __________________
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I can understand an axle ratio change regardless of how minor for "noise abatement" where required. A ratio change is as simple as you or I being able to drive out of drone. The vehicle is evaluated at a specific spec determined by the country of destination. Export exhaust was seldom the same as production for many US productions heading elsewhere.
Maybe substantiating Hib's comments was the change to 3.33 ratio in the M6 cars during C4 production in '89. '90 L98 cars got these also. Hib's reference to noise I'm sure had nothing to do with noise abatement but a drive-line issue as he mentions a tooth count issue. The Corvette 3.54 was a 46/13 combination but years later the 3.55 as a 39/11 tooth count returned to the Dana 44HD. Seems to maybe hint there was likely an issue with the original 3.54.
GM SPO shows axle codes in '90 only for the 3.33 and the 3.45 but then mix '91 & '92 production codes into one chart and again mention 3.45 and 3.54 but no 3.33 references. '91 & '92 3.45 CQR(GM3) and 3.54 CQX(GH0). An SPO error? Maybe.