LegoTechnical

Hello This is the first 4 wheel drive car I've built but after testing i found it can barely move around on bumpy/uneven ground. Furthermore the axles that connect into the steering hubs tend to just pop out with too much torque. What am i doing wrong, and how can i make this more competent off road? I know that battery box could probably be in a more balanced place: i stuck it on the back just so i could test it, but I'm pretty sure power isn't the issue: two XL motors geared up and knob gears (the differential too disengaged when i tried using it) should be more than enough. I've checked batteries and things like that, and i don't think that is the issue. So i don't understand why it isn't as competent as i expected off road. Frustrating.