I'm building an OBD2/0411 driven tuned port setup and built an 02 4l60e to go a long to install in my 88. My intention is to keep the cable driven speedometer with the 4L60e. I have the drive gear secured to the output shaft, a TH350 "bullet" and a length of aluminum pipe to use as a housing in the tail shaft housing. My question is: is the driven gear held in the bullet by tension alone? Every tail shaft housing I see has a wall with a relief opposed to the gear, but I don't see how that could make contact for any length of time without wearing the gear away.

 

Is the gear driven by tooth angle towards that metal or away?

I am not clear on your planned mods to achieve speedo drive, but if you don't have a Chevy (small gear) 6" th350 tail housing and the 700-to-6bolt-4L60 adapter from advance adapters, you may want to start there.

 

Given that the speedo spins in reverse, I think it's safe to say it's driven both ways, and that's my fear.

I'm using the 6 bolt f body tail housing, the small diameter th350 bullet, and planning to drill the housing and secure the aluminum pipe with jb weld or a similar product. It won't be under pressure and there's minimal side loading to worry about it coming loose.