Speedo Gear?

[Michael Yount]

I'm confused too - it's not just you. I'm pretty comfortable in the T-5 realm, but not the autos. I have no idea what the c4 came in or didn't - and how compatible it might be or not. One thing that does make sense to me is this - hook the speedo up with the gear that's on it - if it doesn't have one on it, buy one with a big number (21 or 23 teeth). Then compare your readings to mile markers on the Istate (odometer) and to timed runs between mile markers (speedometer). Then you'll know how far off you actually are. At that point we may be able to suggest alternatives. My best guess is that they don't make enough teeth on the driven gear to correct yours - and you'll have to either 1) put in a speedo box, or 2) replace the drive gear in the tranny with one that has fewer teeth (drop from 8 to 7, or 7 to 6), or 3) put taller tires on the car to help. But I don't think anyone can be specific about any of that unless/until we know how far off it is with a particular gear in it to start with.

 

[92Frankenstein]

Thanks for all your help M. Yount.

I will just buy the 21 speedo and find out how off I am and return with results for your help

Thanks again, as you were of the few to offer any advice.

Brian.

 

[Michael Yount]

Don't take it personal Brian - I think this one is a bit of a mystery for everyone. I too usually don't volunteer anything if I don't think I can help. Your work here may ultimately clear it up for everyone else. But you do know this thing is gonna turn some highway revs and probably not run more than 110 MPH, right?

 

[92Frankenstein]

Don't take it personal Brian - I think this one is a bit of a mystery for everyone. I too usually don't volunteer anything if I don't think I can help. Your work here may ultimately clear it up for everyone else. But you do know this thing is gonna turn some highway revs and probably not run more than 110 MPH, right?

Yea, I am not looking for high speeds, im not even going to do any highway traveling in the car. Just a cruiser.

I also plan on putting in an 8.8 posi with 3.55 gears, so that should help all together as well.


Brian

 

[SCcopcar]

The speedometer drive gear is on the tailshaft of the tranny. Overdrive will not affect the speedometer driven gear choice.

 

[Michael Yount]

SCcopcar is correct - part of my earlier confusion - thanks for clarifying.

 

[92Frankenstein]

Here we go again.

So what are you trying to tell me, it will read the same as an AOD with whatever gear I purchase. EX. 21 tooth will read as acurate in the C4 as AOD?