hey guys whuts up i renctly purchased an 89 lx with a 5.0 with a 5spd. As am driving the speedometer is off over 20 mph I put a new speedo gear but that did nothing any suggestions would be greatly apperecated.

 

You need to find out what gears your running, your tire height if it'sother than stock, and whether or not the transmission is a stock 5 -speed ('89 had a 7 tooth drive gear). Stock tire revolutions per minute are 815.

To get a quick estimate of what rear gears you have: Raise the rear wheels. Watch the driveshaft and count how many turns it makes while you turn one of the rear wheels one rotation. You may need to make a simple penmark on the driveshaft. The number you come up with is your gear ratio (3.55, 3.73, 4.10).

http://mustangpartstech.com/SpeedometerGears.html

More info is posted on this site.

Transmission Drive Gear: Located in the tail shaft of the transmission. Sizes available are 6, 7, and 8. Size 6 was original equipment in some 4 cyl T-5 Transmissions.

Speedometer Driven Gear: Located at the end of the speedometer cable where it plugs into the transmission. Sizes available are 16 - 23.

Speedometer Driven Gear Teeth =
(Drive gear teeth x rear axle ratio x tire revolutions per minute) / 1000

 

get the tag number off the trans, you can decode it on http:www.ddperformance.com on the t5 id link

and figure out what rear gear you have, prop the back and spin the tire and count ds spins for that, rotate the tire exactly 1 turn, if the ds spins 3 1/2 times you have 3.55's, a little over 4 times 4.10's and so on

also see your door tag, under "ax" will be the original gears , m=2.73, z=3.08 , e= 3.27 (aod's only)

that way you can tell what gear you had, and what you will need (also on the d&d site)

if your trans is a 8t drive gear (newer t5), you cannot correct past 3.73's, you need to change the drive gear which is c-clipped on the output shaft , you would want a 6 tooth if you diddo that, it's the black one

 

my uncle and I think that this car was oringaly a 4 cyclinder car. we pulle the old speedo gear out and I think a 20-23 tooth was in so we put in a 16 and the drive gear is pink does that mean I need to put a black 7tooth drive gear in?

 

on cj pony parts a 6tooth gear is pink and the 7tooth gear is black