Engine/Transmission (1998.5 - 2002) Electrical issue.

[firefighter]

I have this problem, with shuttle shifting, I have been told that this is an electrical problem, one suggestion was to remove the voltage regulator to the outside of the alternator I have done this and it seems to fix the problem, however, I now get the check gauges warning and the voltage is at maximum on the gauge, I have used a multimeter to check and it reads normal, is there another fix for my problem I am going to put the alternator back to factory specs as the new problem is too annoying. Thanks in advance for any assistance.