th350 turbo speedo leaking

[impco lpg]

my th350 trans speedo cable is leaking. i have replaced the seals for new ones, the outer seal o ring has worked but is still leaking from the inner seal. this is a common problem. has any one got a fix for this. ?

[bd]

Remove the speedo driven gear and its support bushing (sleeve) from the transmission.  Slip the gear out of the bushing and inspect the shaft of the plastic gear for concentric scoring and a groove worn into the shaft near the cable end.  If the gear is grooved from seal wear, the gear will need to be replaced.  Now, slip the gear back into the support bushing and wiggle the gear from side-to-side.  If there is more than ~0.005" of side play in the gear shaft, replace the support bushing, as well.

[impco lpg]

thanks for your help i will try that when it stops raining  
i should have replaced it all i think.
cheers neil