After I did my motor and trans swap, v6 to v8 my speedometer was working, well i parked it at school one morning and when i went out after school my speedometer wasnt working anymore. Well i thought my cable or housing broke but when I had it in my shop today the cable was fine and so was the housing, the speedometer even moved while I was turning it under the car snd went to like 60mph. Any ideas as to why my speedo quit working? My teacher thinks my gear is stripped, my dad thinks the gear moved in the tailshaft. If it is the gear can I use 1 off a th350?

 

Only one way to find out
Remove the cable drive unit from the trans and check both gears
If the clip that holds the drive gear ( green in pic ) onto the shaft breaks then the gear will just spin freely

 

I can't get the speedo cable mount off though sadly, I robbed the tail shaft off an 83 camaro 700r4 but failed to see the mount had rtv on it. It has been cracked and damaged and the po put rtv on it to seal it. Are those gears known for breaking? And could I use the red/orange gear from a th350? I remember installing the gear on my trans before I installed it and it was the same color. I'm going to put it on the lift later next week and take the tail shaft off so I can inspect the gears but want yo have new gears here just in case it is broken

 

Well I found my issue, my drive gear teeth are sheared off. Iv gotta try and find one

 

http://www.transmissioncenter.net/sp...__va.htm#Cable

 

Think I found my issue, maybe. It looks like my drive gear is one out of an electronic speedo assembly ( has the cone shaped gear head) instead of the standard mechanical setup. Ordered a new one from that site and will install it when I get it here.