I just spent all weekend trying to replace my tranny with no luck. I went to a yard and got a replacement 5 speed SI tranny (cable)for my 89civic SI. It looks exactly the same but it wont slip into the clutch. I took off the clutch and found out that the spline on the new tranny I got is different then the one I had. Is it a possibility that they made 2 different d series SI Trannys.....2 different style splines?? Anyone know what hapenned here?? I do have a racing clutch but I wouldnt think that should make a difference. Any help would be much appreciated.

 

it sounds like you got ahold of a trans out of an 88.I know that the transmissions from 89-91 have the same amount of teeth on the input shaft, and the 88's are different.

 

ive heard that some have 20 splines and others have 21 or 22 splines.