Wrong speedo gear? Manual, AOD different?

[92lxaz]

I ordered a 23 tooth speedo gear and it is slightly different than the one I'm replacing. When I have the new one in the clamp won't go on. The teeth are longer as hopefully the pics show. Also there are grooves at the base on the old one but not on new, not sure if this matters but it is another difference. After looking I've found both types for sale on line. First time I've added pics, hope they work

This is like the in the car now
http://www.performancepartsinc.com/images/23tooth.jpg

This is the new one
http://www.transmissioncenter.org/23TG.jpg

Here's a bad picture of mine
View attachment 215028

 

[Repostyle]

The one on the left looks correct for a fox body manual trans, what year car is this going in? And yes, AOD is different from 5-speed. The AOD alignment shaft on the end is about 1/2 inch longer (the top in your pic).

 

[92lxaz]

Mine is a 92 with manual. So was the incorrect one in my car this whole time (one one right)? I tried the new one and the c-clamp didn't seem to want to fit, I probably had it facing the wrong way or need to get a little tougher. Trying to be careful with such a fragile piece.

 

[92lxaz]

Got it in, seems to be fine. Tach still doesn't go over 3K though. Thought this would be the fix.

 

[Mustang5L5]

The white 23 tooth is not a ford part. It's a Chrysler part. There is only one.

The speedo gear has nohing to do with tach signal. Not going over 3000 rpm is a common problem although the cause escapes me right now. It's an electrical prob though

 

[92lxaz]

Ok thanks for clarifying. I did hear that about the tach being electrical, something about the signal between the coil, distributor or something of that nature. Not sure where I heard that. Then someone had told me that possibly the speedo gear could affect it, although my speedo was never wrong and it didn't make sense regarding the tach, I figured I try it. Let me know if you have any suggestions for the tach issue. Thanks for the help.