I just had installed a new transmission and a new clutch, after driving it for the first time today in almost a month, I have noticed some differences that I am not happy with.
1: It seems to be geared lower, ex: old tran 5th Gear + 4K RPM = 90 Mile/Hr
new tran 5th gear + 4k RPM = 80 Ml/Hr
What could this be from? Would it cause worse fuel economy?...
By the way 1997, LS 5sp 4dr

 

Sounds like they replaced it with a GSR transmission. It definitely isn't a bad thing since it will accelerate faster. The higher crusing RPM's have no effect on fuel economy.

 

is it as simple as replacing a ls transmission with a GS-r one, It sounds too easy to me.

 

All B-series transmissions (but not cable on a hydraulic clutch system or vice versa) are interchangeable. It is that easy.

 

I recently went from an s4c tranny to a y80 tranny...Gas milage is damn near the same...It was a little too easy...My rpm's are up though, the opposite of this guy...I went down a peg with the y80...