Hello, I am new to the forums and have been doing research prior to joining and was wondering what all needed to be done to swap the fifth gear from a d16y5 transmission onto an s20 transmission. From what I read it is a direct swap, but im not exactly sure what gear(s?) it is that i need to swap over. If you can provide diagrams that would be handy. I haven't done any transmission work before so I want to be sure i know what it is that im swapping before i do it. (both transmissions are already out and ready to have the gear swapped out.

 

Unless the S20 is from a Del Sol Si then it has the same .702 5th gear as the D16Y5.

 

are you sure? i thought the s40 from the y5 had the longest gear ratio of the d series. would that be the final drive then?

 

I'm sure. Y5 has a 3.722 final drive just like the Y7 hatchback and 88 CRX DX. Unless you have the corresponding engine and ECU, a longer geared trans is going to hurt more than it helps with fuel economy.