I just finished a ton of work on an ole kodiak. When in 4wd diff lock mode, the rev limiter stays on. Who knows of an override fix to that problem?

 

There is no limiting in reverse.

 

On the newer grizzlies, the rev override button overrides the limiter while diff is locked. Gray button on left handlebar.

 

On my 2005 450 kodiak its the red button on the left handle bar I believe.

 

Correction to my last. I agree it is the gray button the red is off and on which I never use just the key..

 

The reason diff lock can only be engaged while in low range or has a rev limiter is because with both front wheels locked the the ATV is very hard to steer.

Diff lock is usually just used for a short bad situation or section of trail where regular 4wd (3x4) is just not enough and you need that extra traction.
You could kill yourself or your arms at least with diff lock on for any length of time or going any faster then 20 mph.
Even if there is a way to engage diff lock while in high range or no rev limiter it would be one miserable machine control or ride.