I have a 88 ef civic with a std 4-speed d series cable tranny.Im looking for a 5 speed cable tranny to swap out my 4 speed but its hard finding one that is cable non the less finding one that doesnt have any shift problems.So I was wondering if the internals of a hydro 5 speed d series would swap into a 4 speed tranny case with no mods since 5 speed hydro trannys are all over craigs and egay.Anyone?

 

Nope.

 

Is there anything I can do to the 4 speed tranny that will make it a 5 speed?

 

Turn it in as a core and order a remanufactured 5 speed trans. If you have a true 88 it will have a 21 tooth spline for the clutch. You can use the 89-91 but you will need to change the clutch disc to the 20 tooth design.

 

You'll need some parts from a 5-spd.

shift fork rod, 5th shift fork, reverse lockout and bolts, 5th gear, 5th hub/slider/synchro. Not really worth it just to be stuck with the long 4spd gears. Cheaper to just pickup a 5spd than to convert the 4spd to DX or Si gearing.