Change gear ratio now gage is off - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

reman519 · 09-16-2007, 07:03

I Changed my diff from 3.08 to 3.55 now I think I'am 20km off what do I have to do to fix it ? chang speedo??? it's a 1989

Nathan in MN · 09-16-2007, 11:00

You need to change the speedometer gear in the transmission. Pretty simple, if you look on the tailhousing of the transmission you'll see a fat black cable going into the driver's side. The clamp that holds it in place comes off with a 7/16 wrench, and then the cable and gear pull right out. There's a little metal locking tang that holds the gear to the cable. Pull that off and the gear will come off. Bring that gear to your friendly local Ford dealer and tell 'em you need a gear of that same style, but with 21 teeth. This is assuming you're running stock outside diameter tires. Put that gear in, smear a little silicone around the outside of the piece that goes into the tailhousing, put the clamp back on, and you're done. Five minute job, and if you're skinny like me, you can do it without ever jacking up the car!

BigJon · 09-16-2007, 15:25

nathan is very correct.

so, how do you like the 3.55s? nice, huh!

reman519 · 09-16-2007, 17:18

not sure yet I have not driven the car all that much yet. I need to tow my trailer I'll find out more. I found out that one axel shaft was not that good where the bearing rides. Cound not get one, no one had one, and my car was at my work not at home so i grinded the shaft and put it back in. all new bearings and seals. Need to get that speedo gear next and see if I can get a axel shaft and take it apart and put it back in.. Will find out soon

1989 Grand Marquis wagon 242500KM

The old gear set 3.08 looked like new no marks at all it look new WOW

reman519 · 09-25-2007, 16:07

Got a axel shaft from the junk yard took it out myslef $25 and put it in. I got the 21 tooth speedo gear and have to put it in it's red and plastic??? I can see my trany shofts into 4th still at 80km but I know I going aboy 60km??

Nathan in MN · 09-26-2007, 15:20

Interesting...the 21 tooth gear is usually purple. Hope you got the right style gear. Guess you'll find out when you put it in.

reman519 · 09-26-2007, 16:27

I counted it it has 21??? $13 cnd for the dealer that about $13.09 US now right ha ha

Nathan in MN · 09-27-2007, 12:00

I realize that, but I'm saying that there are different styles of speedometer gears. Like I said though, you'll know as soon as you go to put it in whether you got the right one or not.