I just recently regeared my 99xj to 4.56:1 and now in over drive, around 35-45mph I hear this grinding noise, like if you were to trying to move forward with a manual in 3rd gear from a stop. My rpm's are between 1200-1800rpms between 35-45mph and I was wondering what could cause this? Is this noise something I should worry about? I read about the drive plate (the flywheel or whatever it is called) bolts coming loose and the plate cracking and I checked that. Bolts are tight and the plate isn't loose or cracked. If anyone can help, I'd really appreciate it, the noise is starting to worry me. BTW, I have a 4.0L, AW-4, 4.56gears, tom woods driveshaft (with the correct angle, no, its not vibes), and 35x12.50BFG muds (so like 34.7 or something). Thanks