My speedo doesn't work, and I took out the drive gear attached to it. it was completely smoothed. So I put in a new one and it still doesn't work...did they make these with different amounts of teeth? I didn't know if the colors are important, just took one from a diff tranny and popped it in.

Also, unrelated question...everything from my air filter to oil and even tranny fluid has a slight gas smell. Tranny fluid is a bit burnt, my teacher said my tranny might be on the way out. The diff. fluid was black and chunky too. Should I be expecting to replace everything?..

I did the lighter test on my oil dipstick, no ignition so I assume the gas smell in it is just because the car is 24 years old.

 

The drive/driven gears must match the rear end ratio or the speedo head won't read correctly.

JamesC

 

There are different gears for the speedometer so you will need to install the right one to get an accurate reading. Since the old one rounded off does the cable turn freely?
You should not worry about the gas smell in the filter, its normal. The gas smell in the oil could be because its running a little rich or maybe the engine is a little worn. Your transmission fluid is probably fine so don't worry about it too much as long as its shifting right. The rear axle fluid should be changed.

 

I have the electronic speed sensor so no cables. The gear was blue, but the ones I got were red and brown. They "looked" like they had the right teeth count. We tested the actual sensor with a drill and multimeter, it works fine the speedometer moves it's just this damn gear...

Oh yea I changed the air filter today...what the hell is with that air box? It's drawing all the air for that 5.0 in through a tiny slot in the filter housing! I'm thinking of getting a performance air filter and box and just hooking it up directly to the intake on the engine and screwing all that half-assed Cold air with huge restriction crap.

 

Thats odd my 86 uses a cable still.

 

I don't know much about the speed sensor...all I know is it has cables that plug into the sensor on the tranny. Would it still use cables elsewhere?

 

The system is either cable driven or electric (there's no mix of the two). Aside from using the correct driven gear size (and manual and auto trans are different), did you take a peek at the drive gear? If it's bad, it may be chewing up the driven gear.

JamesC

 

If you have an electric fitting on the tranny and a mechanical cable to the speedo, can you remove the electric component and install a component to connect the mechanical cable?

 

I meant that there's only a single connection on the trans.

Yes, you can convert (T-5 to T-5 or 700R4 to 700R4) with the correct gearing/housing.

JamesC

 

My Drive gear is fine, not sure why the driven gear got chewed up. After some research I found out the colors are for different amounts of teeth that went with your car depending on your tire size and final drive ratio you had...and the blue one I had was not stock, red is. So I gotta figure out if the previous owner changed the tranny or rear diff. gears.

 

when you test the wires that connect to the electric speed sensor on an 87 firebird, do you know what readings I should get and is it volts/ ohms on the multimeter?

 

Well the car is a 12 volt system however not ever component is running on 12 volts, I'm not sure what that part requires for voltage but typically to check continuity you use ohms. If you get a reading of Ohms then you have continuity, otherwise your multimeter will read OL. That is how you check to see if it's receiving power and is not a broken circuit.

What I did was a physical test: the end of the speed sensor is the same as a bit for an eletric drill by chance so hooked it up and spun it, and the speedometer worked. That's how I know it's not the sensor.

I would have to use AllData at the college and find out what volts the speed sensor requires to answer your question, unless it is part of the 12 volt system. I had thought only sensitive devices like computer circuits don't use the 12 volts but I am probably wrong.