just so Im not gonna run into suprizes whats the procedure for speedo drive gear replacement?
I know the tailshaft needs to be removed and im sure the drive gear is slipped onto the output shaft.
whats holding it on etc.

anyone have a clue?

Drop the driveline.Remove the speedometer cable and drive assembly from the extention housing.Remove the extention housing.There's a small spring-clip slipped under the speedometer drive gear;depress the spring and slide the gead rearward and off the output shaft. Don't lose the spring-clip.Don't forget to use a drain pan. Reverse procedure to assemble. Anyone else?

You hit it all. You may even want to bend that spring clip back a little for a smidgen more tension when you put it back on. I run copper RTV around the gear housing when I plug the speedo back in. Not a requirement but It helps me sleep at night.

There "may" also be a steel sleeve with O-ring on the output shaft too. It's for sealing the yoke when it's inside the trans. It slides off too. May take a little tapping but it's not usually on too tight.

Mark

This photo shows the clip ...
Now the photo is of a 700R4 ... not a Turbo 350 but the photo does illustrates where the clip is and how it works ...

thks guys that a piece of cake!

I hope you used the correct drive gear for the 700 trans.

A t-350 will fit , but is the wrong diameter .

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If you can't fix it with a hammer, you have an electrical problem.

nope I got a TH350
and if you math wizards can check my math for correct speedo gearing
27.1 inch diameter tire
tire revs per mile 768.0
3:73 rear ratio
speedometer calibrated at 1000 revs per mile.
I come up with a 7 tooth drive gear (on tranny shaft)
20 tooth driven gear (on speedo cable)
that will give a .50 margin of error.
Id rather the speedo read a bit high than low.