Can my Transmission out of my 1995 sse go into a 1994 ssei

I believe the 94 and 95 transmissions are swappable. The difference being is that the SSEi'* have the 4T60-HD and the SE has the 4T60-E. The difference between the two have to do with duty use, gear ratios and I think the TCC'* are a bit different.

Most swaps are for the HD to take the place of E and not the opposite. IMO- I would recommend that you rebuilt the SSEi'* or find one that'* in better shape at a bone yard. You wont like that E in the SSEi.

all the "E" stands for is "electronic" according to the GM breakdown of the transmission names.

ok thank you

There is an HD vs non-HD difference between the two you mention. I'm not sure on the 4T60'* like I am about the 4T65'*. But GM was changing a lot of stuff during the time they used the 4T60. This included changing tooth counts, pitch etc etc that make swapping parts from one trans to another difficult. You would want to stay with an HD transmission for the gear ratio, HD differential and correct passenger side axle length.