Savage XS issue

[KenC]

Have had this truck over a year now and have really enjoyed bashing with my son and his truck.
Was jumping a small ramp the other day and landed funny.
Then I noticed only the front wheels were pulling.
Where should I start looking? Diffs?
Been running bone stock on 2S and that is plenty fast enough as small as it is.

 

[X]

I would look at the grub screw holding the drive cup on. You have one in front of and behind your transmission. look at the one in the rear of the transmission for what your described. In the picture below they are part# 86094. It is very common for these to back out and fall off. If this is the case, make sure you use some loctite on the threads when you reinstall.