OneGearhead

ok, i saw where Ob posted the gear swap gears, but........'92 GT with 3.08's factory.....im gonna go to 3.73's....which gear do i need ?? and im gonna change the tranny gear too so everything will be right.....do i still use the 21 tooth gear ? or what.....and whats the diff in the '87-'89 and the '90-'93 that they use diff gears ??

nemethjames1

not sure on what gear you need coz its not listed, all i know is the 90-93 trans have a different ratio in first gear or somethin like that

69mach1377

Do the math ratio thing, comparing the original final ratio to the new one and solve for X.
So for this example,
X=21*3.73/3.08=25 teeth
Next math lesson?

roundman

first gear don't matter as far as the speedo reading goes. and you don't need to change the tranny gear either, it's built into the tranny output shaft and you'd have to change the whole shaft out to change it. I gave OB those speedo gears info and it's posted at the top of this section I believe or at the top of General tech. the difference in the gears is due to a change they made in the tooth count on the tranny shaft gears or either the OD gear ratio or both I believe. You will like the 3.73's, trust me!

69mach1377

Are you guys talking about the little plastic speedo gear? On older cars, this has to changed when changing your final drive ratio due to a gear swap and/or tire size. Maybe on newer/electronic cars it can be compensated for some other way?

roundman

yeah, they didn't go electronic until mid 90's before that you still have to change the little plastic gear out when you change the rear gears. newer electronic ones can be done by a tuner chip change that just plugs in.

nemethjames1

but roundman on that speedo recal topic OB did, it dont list for 373's with t5 for 90-93...?

69mach1377

That's why you do the math...and choose the closest one available.

nemethjames1

well i dont do math[:@]

69mach1377

That's what I thought, and that's why I did it for you...your welcome.[&:]