I never noticed this before but at one spot on my way to work I am turning pretty hard before stepping on the brake pedal. When I do step on the break pedal the steering seems to slip a little bit? Any ideas?

 

I believe your brakes and your steering are both powered by the power steering pump.

 

The power brakes use hydraulic pressure from the power steering pump, so if you're turning as hard as you can and then hit the brakes, it might cause it to feel a little funny. I notice the same thing sometimes at low speeds, like when parking. It seems more noticeable when it's colder outside.

 

It's a hydraboost brake system.

 

IMHO the RPM's of an idling diesel don't produce enough volume for the power steering pump to keep up it you are turning alot (like backing a trailer) I ahve a spinner on my steering wheel so I can turn the wheel pretty fast if I need to when backing up. The power steering pump seems to "growel" alittle also.