Can anyone tell me if the diff yokes are interchangeable between the heavy duty IRS M80 out of a VX-VY and the VS heavy Duty IRS M80 ? And will the VX-VY housing & axle cups be the same as the VS ? Is there any differences in the pinion shaft splines ? All I know is the VR-S-T had a round face yoke while the VX-VY had a triangular yoke...and that a VT diff will fit a VS... I'd really like to know as much info as I can on the IRS diffs.