I swapped rear gears in my 92 camaro and now the speedo is off so I need to do a change in the Vss signal. But i'm not going to pay for a $150 box! If anybody knows what the signal looks like on an oscilloscope at what speeds, I'd appreciate it! I'd like to build my own little box with a micro-controller.

Thanks

 

Well fist off its an analog signal generated by a fixed magnetic feild thats interupted by the reluctor wheel on the speeodmeter gear on the trans. I would personally just change the speedometer gears out and be done with it instead of adding something else that can further cause you problems down the road. If you call a dealer they can most likely tell you what gears youll need for the set up you have so why not just take that route?

 

M is right, you don't need anything electronic just a different gear. To do it electronically would require changing pulse rate. Gears run approx $14 or so

 

That is what I initially was going to do but my uncle who owns a tranny shop said that you'd have to get a bigger tail housing to swap the driven gear any bigger.

Have you guys swapped gears on vehicle w/an electronic speedo?

I'm only going from a stock 2.73 to 3.23s

 

I did that same conversion on my '87 Convertible with a 700-R4 - 2.73 to 3.23. It required the driven gear with the largest # of teeth available - like 42, if I remember corectly. The gear was like $15 from GM.

 

No doubt the driven gear and the drive gear has to be changed? Not too bad on a 700R4, but what about a T5?

Andy.

 

I dont see why the tailshaft would have to be changed. The gears arent really any bigger its just the number of teeth on them that matters. A combination of both gears being changed should give you the neccessary ratio for your speedometer to work.

 

Some times the VSS Sender has to be changed if the outer gear on it is less than 40 teeth originally and the new is 40 or more then a new vss housing is needed to compensate for the larger diameter gear. I have heard of some people getting away with out changing it and others that didn't ended up eating up the vss gears and ended up having to replace both the inner and outer and the sender

 

here is a pic

 

Does the T5 trans have to be stripped down to replace the drive gear?

Thanks.
Andy.