I have one and it is a great truck. Sounds like he needs new
clutch shoes. I had the same problem. Mine wore out quickly, but others have not so it might have been a bad batch. I replaced them and it runs like a champ now. The part number for them is 149552
A guy recently (about a month ago) bought a mommoth from one of the local shops. I saw him yesterday with his old t maxx and asked what happened to his new truck. He said that after about 10 trips out to the bash pit it was too trashed to bother trying to revive. The guy is a hardcore basher, but his maxx, savage, and other stuff lasts about like it does for eveyone else. I wonder if the mammoth may be just another of (the many) POS MT's that have been rushed of late to market to take advantage of the craze.
As for this, a Mammoth is made for racing, not hard core bashing. It will take abuse from races and light bashing, but it is not made to excel in a "bash pit". That is what Savages and the like are for.
Joe