speedometer gear/VSS question

[riceslayer302]

my speedometer is not working, it hasnt been since i got the car. i recently changed the cable and found that didnt fix my problem. i was told to pull the VSS sensor and check the plastic gear at the end of the sensor.

i pulled the VSS out of the tranny and there is no gear on the end of it, just bare cable. i looked up inside the tranny and could see a gear, but it is facing the front of the car, isnt that the other gear that turns the one i am trying to replace? is it possible that the previous owner didnt put a gear in the tranny? did it break and go up into the tranny? im not sure, but i do want to fix my speedo so how does the gear go onto the VSS? is there anything extra i need to do to make it work???

 

[GearHd6]

If you've got a Mustangs Unlimited book, they have the chart that tells you what gears work for each axle ratio. Look inside the hole in the tranmission where the VSS goes and see what color that gear is on the tailshaft. Yellow, Green, Black?

The gear that goes on the VSS just has a little metal clip that locks the gear into the grooze in the VSS, piece of cake.

 

[riceslayer302]

i looked inside the hole and saw a gear up inside the tranny, is that the gear that was on my VSS or is it the other speedo gear? should i try to get it out?

 

[GearHd6]

That gear you see in there is attached to the tailshaft. Someone probably removed the gear from the VSS. I'd look in there and try and see what color the gear is. Pull out your MU catalog or look online, the pictures will tell the story.

 

[riceslayer302]

ok, so that is the metal gear that stays inside the tranny.

the color of the gear in the tailshaft should be the same as the one i am going to put in? the car has 3.55's and is a 1990 so it should be a 23 tooth white gear correct?

to change it i get a new gear and just slide it onto the shaft where the speedo cable comes through the sensor???

 

[GearHd6]

If the transmission is ACTUALLY a 1990 tranny it should have an 8 tooth gear on the tailshaft. The teeth are kinda tough to count but if you can count them and get the color then that would be best. If you've got the 8 tooth and you went with the white 23 tooth VSS gear your speedo will be off cause that combo is for 3.73's.

 

[riceslayer302]

im pretty sure the car has 3.55's. with the wheels off the ground i had my friend turn the tires and the driveshaft spun 3 1/2 times

what gear should i use or where did you get the info?

 

[GearHd6]

Once you get the info from the tailshaft gear we can figure out what VSS gear you need, without that info its all a guess. If theres a yellow 7 tooth gear in there or a black 6 tooth in there it'll throw everything off. I just know that 90-93's came with an 8 tooth gear. That doesnt mean that tranny hasnt been swapped out in the last 17 years.

 

[riceslayer302]

it would probably be easier to match the casting number on the tranny then to count the gear teeth dont you think?

 

[riceslayer302]

i just checked, it LOOKS like its 6 tooth, but i cant totally see. it is white. how bright of a yellow would it be? there isnt a chance its a faded yellow is there?

the tranny says borg warner automotive on the side and there is an aluminum tag with ID numbers on it, could we tell by the numbers on the tranny what year the tranny is and accordingly figure out what gear is inside it?

 

[GearHd6]

There is no white tailshaft gear so its most likely a 7 tooth yellow gear.

Yeah get all the info off the tag and we'll run the numbers.
The number should read some like, 1352-*** get those last 3 numbers.

 

[riceslayer302]

well i went to mustangs unlimited today and used their speedo chart, according to them, 3.55's in a manual tranny uses a 20 tooth black driven gear. so i bought it, it was all of 7 dollars. installed it, and my speedo works, but its about 20mph off... when im going 60mph, my speedo reads 80mph.

i was looking at my friend andy's gear today, his is red, and he has 3.55's too, and his speedo is dead on... but mustangs unlimited says red is 3.73...

what should i try now? if the car had 3.27s would it make the speedo read higher than im going or would it read lower??? should i get 3.27 driven gear and try that? or get the red one?

my friends tranny also has the same 7 tooth yellow drive gear... maybe i should get the red?

 

[GearHd6]

well i went to mustangs unlimited today and used their speedo chart, according to them, 3.55's in a manual tranny uses a 20 tooth black driven gear. so i bought it, it was all of 7 dollars. installed it, and my speedo works, but its about 20mph off... when im going 60mph, my speedo reads 80mph.

i was looking at my friend andy's gear today, his is red, and he has 3.55's too, and his speedo is dead on... but mustangs unlimited says red is 3.73...

what should i try now? if the car had 3.27s would it make the speedo read higher than im going or would it read lower??? should i get 3.27 driven gear and try that? or get the red one?

my friends tranny also has the same 7 tooth yellow drive gear... maybe i should get the red?

Theres wayyyy to many combinations, you should have taken my advice and got a better look in there or got the number off the tranny tag. Good luck now, you'll have a nice gear collection. The tranny number would give you the number of teeth on the tailshaft gear as long as its never been changed.

My guess is that you'd need a 23 tooth gear to correct the 20 mph difference.

And your stock set up with the 3.27 speedo gears would make your speedo read faster with your 3.55 gears.

 

[riceslayer302]

i did take your advice, its a 7 tooth gear, im 99.9% sure of that. the only thing is im not sure what ratio my rear end is...

 

[GearHd6]

The tranny tag # would be nice to have also, if the tags even on there. That tag can shed a lot of light on what you're running for a tranny, right down to tranny gear ratios and torque ratings.

Your only choice is to go bigger on the VSS gear and the biggest one you can get is 23 teeth. If the speedo still reads to fast then you'll have to change the tailshaft gear to an 8 tooth which will be a nightmare.

 

[TRWXXA]

i did take your advice, its a 7 tooth gear, im 99.9% sure of that. the only thing is im not sure what ratio my rear end is...

You really need to turn the rear wheels more than once to get an accurate count of your rear end ratio. It's hard to tell the difference between 3 1/4 turns of the driveshaft and 3 1/2 turns, or 3 1/2 vs. 3 3/4.

Put a mark on your driveshaft, and have someone turn the wheels 10 times, while you count the driveshaft rotations. Do this a couple of times to make sure you don't mis-count. 31 rotations would equal 3.08s, 33 would equal 3.27s, 35 or 36 would equal 3.55s, etc.

 

[GearHd6]

You really need to turn the rear wheels more than once to get an accurate count of your rear end ratio. It's hard to tell the difference between 3 1/4 turns of the driveshaft and 3 1/2 turns, or 3 1/2 vs. 3 3/4.

Put a mark on your driveshaft, and have someone turn the wheels 10 times, while you count the driveshaft rotations. Do this a couple of times to make sure you don't mis-count. 31 rotations would equal 3.08s, 33 would equal 3.27s, 35 or 36 would equal 3.55s, etc.

Yeah that sounds like a pretty good method to me, thats a little more accurate.

Hey TRWXXA... Thats a super nice SSP you've got, I love it. Do you have a link with some more pictures? I'd love to check it out.

 

[riceslayer302]

my friend bill, who you may know through josh bentley, has one of the only remaining connecticut SSP cars around. its 5 speed too!!

 

[GearHd6]

Yeah I know the one, TRWXXA's is a real nice piece. Bills needs SERIOUS work if I remember correctly. I've seen it out a few times.

 

[TRWXXA]

Hey TRWXXA... Thats a super nice SSP you've got, I love it. Do you have a link with some more pictures? I'd love to check it out.

Thanks. PM sent.