trans shifts to 2nd but still in 1st

[TA2SLOW]

Yesterday i had a governor come apart (long story). So i replaced it with another governor out of god knows what 200r4. It has heavier weights and springs but does have the same color gear on it.
I put it all back together and filled it back up and took it for a spin. I pulled the trans into manual low and took off, to have the trans shift on its own into 2nd. How can the trans shfit into 2nd while its still in the manual low 1st gear? The shifter is adjusted perfect.

The governor seal didnt look the hottest or the gasket for the governor cover, could they be bleading pressure off and causing it to shift on its own while in manual low?

BTW the shifts before this all happend where perfect!!!

98 Trans Am
393 cubed
200r4

 

[MeanBuicks]

Looks like you answered your own question.

The reason the transmission is acting like that is that the heavier weights/springs are generating considerably more governor pressure for any given vehicle speed than your original governor. You need to find a direct replacement for your old governor to make the transmission act correctly.