92hatchLX

Well, I just broke down and purchased the motive 3.90 gears and the motive master bearing install kit. Well now I'm facing a problem (not really a big one but ya know...), I can't find a speedometer correction gear for a 92 AOD for a 3.90, but I noticed on the steeda website they offer the 23 tooth gear for the 3.55, 3.73 and 4.10 gears. So how far off is my speedometer going to be with the 23 tooth tranny gear and the 3.90 rear end gear???

5.0FoxBody

I think you'd be pretty close to accurate w/ the 23 tooth white speedo gear... I have 4.10's and w/ the 23 tooth my speedo is still a few mph off (I don't mind too much)...so maybe w/ 3.90s it'll be right on.

Liquid_02

Don't know the drive gear size, but assume it's 7 like the T-5's, that'd be 3.28. But that's as close as you can get so get it.

Ecstasy

see i know my speedo is off because of my rims being bigger atleast im pretty sure its off, ill just worry about it when i install 3.55's though. with 3.55 at 70 mph what rpms will i be turning? i know right now at 70 mph im turning right under 2k rpms and at 80 mph im right on 2k rpms. now keep in mind i think my speedos off.

ikeybmg

a 6 and a 19 will hook you right up bro. a 7 and a 21 is 2:73. a 6 and a 20 is 4:10 a 6 and a 18 is also 3:73

5.0stanger

Well running 3.73, at about 80mph my rpms are just under 3000. My speedo is pretty close, so maybe that will give you an idea.