A likely cause. Another might be a CVD grub screw that loosens up quickly, again somewhere in the front. Also make sure the grub screw is on the flat of the shaft or in the dimple, if there is one.

This truck is an enigma. The other night I can't get the friggin thing to move at full throttle, tonight, I am pushing concrete blocks across the garage floor. I am going to push it hard tomorrow to see what happens. I appreciate the suggestions. More to come.....

Almost sounds like your motor is slow to wind up.
Maybe you will work everything out of it.

Cool,

I don't think the motor is the issue. I shot two short videos of my truggy in action.

This one shows power getting to the rear. Big wheelie on the carpet.

http://www.youtube.com/watch?v=87Z_hB089bs

This video is a no load testing of the differentials. All the wheels spin and the wheels are partial pizza cutters. It is getting there.

http://www.youtube.com/watch?v=o-QKCun3ADQ

Looks fine to me - I suspect it is because of the grease in the CD - buy some 30k...

I am going to roll with the grease for a minute and then up to the 50K stuff. There is snow all over the place so no play outside. Focus is shifting to running 100+ with my GTP and HPI Super Nitro.

The grease is why the power is unloading to the front.

Thanks...I may have to make that change sooner than later...I did notice on the video that the fronts lite up faster than the rears.

It was a great day to get the Truggy out and it was great for about 10 minutes. The 1520 on 5s and a 15t pinion with stock gearing was a beast on the road and in the grass. It was fast as heck an the 1520 stops on a dime. The grease though, did not last. After tromping on it for a while, I lost forward motion. Next stop...locking the center. Once I get it running where I want it..6s and gearing up is next.

There is no need to lock the diff, just use the proper silicone oil as you've already been told

So what was the problem? What was moving and what wasn't?

Truggy doesn't go...No more!!!!
 

Truggy doesn't go is not the case anymore. I locked the center diff using hot glue and the truck is insane on 5s. Wheelies and front and reverse are as easy as throttle application. The 1520 is a beast of a motor and the Mayhem is a solid basher. Looking for wheels and tires for an onroad set up also.