I know I can count the gearing, but does anyone know what gearing these Grand Marquis Colony Parks typically had in 1986, when they came with the 5.o multipoint fuel injection and AOD. I sense it may be a decent gearing, numerically higher then the usual late 70's highway gears
There should be a tag held onto the cover by one of the cover bolts. It has two lines of info; look at the bottom line left end, it gives the ratio, and whether it has a limited-slip differential or not. For example, Roger's tag reads "3 08" meaning it has an open diff with a 3.08:1 ratio. The '87 CV sedan I had years ago, it read "3L27" which was a Trac-Loc diff with 3.27:1 ratio. Now, if your tag's gone, the true gear tooth count is on the outer side of the ring gear, for which you'll have to jack up the rear, set the axle on jack stands so the wheels can rotate, then, after putting the trans in N, you can rotate the driveshaft to find the tooth count. Divide the large count by the small count, that gives you the ratio installed. 3:08 is stock, 2.74 was for a highway cruiser, and 3.27 and 3.55 were for vehicles equipped for towing.
The info tag on the door jamb will have an axle code that will indicate the ratio. Check out this web site. https://gmundcars.com/ford-axle-code-chart/
great tips, thanks. The doors sticker says a single 5, so I guess thats an open 3.27? I'll check the tag on the axle housing once I get my Suburban off my lift.
