'91 300e 2.6 - No upshift

I replaced the governor gear last month. Today it appears to have failed again. After the first repair, I did notice a change in shifting. It seemed to shift at a higher rpm than before but still smoothly. I thought this might be because I had messed with the throtle cable eariler when diagnosing the original failure and had not gotten back to adjusting it.

Not wanting to make this a regular repair, what should I be looking at as a possible cause for repeated failure. Could the governor itself be defective and that is causing it to strip out the gear? I"ve seen posts about removing the secondary pump, is that something I should pursue? Also, I noticed that the drive gear on the main shaft showed some wear. Is it possible to replace that without removing the transmission?

You help is appreciated as always.

Craig