Hey all,

A month or so ago, I changed my trans oil and diff fluid to Amsoil Severe Gear. I was also mucking about with the transmission installing some secret parts to improve shifting feel (can't talk about or specify). Thus the trans mount and crossmembers were removed, and there was some force applied to the trans case.

Everything was torqued to spec, following the service manual, but ever since then, I've had a rattle. My buddy said it sounds like it's coming from the headliner, but to me it sounds like the trans tunnel.

Only between 42 and 48 MPH, I'll get this rhythmic rattle like wronnnt-wronnnt-wronnt... It happens in 3rd and 4th gear, so it's not gear dependent. I'd say the rhythm is once per second or so. Frustrating since I'm in that speed range a lot.

In 5th gear occasionally between 50 and 60 MPH, I'll hear an oscillating pitch hum, where the pitch goes up and down once a second. No rattle, but figured it was the new oil or something.

I've got the Perrin Pitch Stop, Trans Mount, Driveshaft Lockdown, Rear Diff Lockdown, etc. So NVH is to be expected, but these rattles never occurred with just the Pitch Stop, Trans Mount, and Diff Lockdown.

Also, I'm sure this is just the tension springs in the trunk lid rattling, but when leaving a stop, if I'm not smooth enough, I'll get this rattle from passenger rear. Exhaust isn't touching the body, so not sure what's doing it.

Any thoughts or advice? I know I could drown it out with music, but I like listening to the car, lol. Thanks!