I've got a rattle type noise coming from under my 98 civic cx in the center and I'm thinking the worst case would be a tranny problem. I put in a used tranny from an EX last June and it runs great. How would I determine if I have a differential problem? When it's sitting on the ground the axles are tight in the tranny. If I put it up on an angle on ramps, the front up, there is some play.
I can't find anything loose except the axles but only when on the ramps. I replaced my right axle because I have a lifetime warranty but the noise is still there. It happens mostly on acceleration in first and second. I can also hear it when I drive up my steep bumpy driveway.