I work for an armored truck service which falls into the Department of Transportation section. I've been told we get a guaranteed 40 hour work week worth of pay even if we don't work the full 40 hours but we don't receive OT pay until after 50. Now I'm told, they will not do the guaranteed 40 hours of pay and will still not pay any OT until after 50. Just looking to see if they are trying to slip one past everyone of if this is a legal way of paying wages. Last I checked, OT is to be paid after 40hrs but I could be wrong. Thanks in advance.

Not sure where you live. Here in N.C. we has a state labor board to contact. They will know the answer you seek.  Betting you are screwed by your company.

From the US Dept. of Labor website:

"The federal overtime provisions are contained in the Fair Labor
Standards Act (FLSA). Unless exempt, employees covered by the Act must
receive overtime pay for hours worked over 40 in a workweek at a rate
not less than time and one-half their regular rates of pay."  You can go here and see if you are a "covered" employee. http://webapps.dol.gov/elaws/whd/flsa/scope/screen9.asp

Depends in part on the weight of the vehicles you drive.  There's an exemption to the Fair Labor Standards Act (fed law mandating OT at 40 hours) contained in the Motor Carrier Act. If you're driving trucks over 10,000 lbs, you may fall under an exemption from the FLSA.  

Talk to the DOL and they'll set you straight.  You can find the local office on this website: http://www.dol.gov/whd/

There's been a fair amount of litigation under the FLSA involving armored vehicle drivers.  http://www.law360.com/articles/427614/armored-car-driver-not-flsa-exempt-judge-rules; http://www.bna.com/drivers-armored-cars-n17179924660/

Do you have a Contract saying you will be paid 40hrs?

No

SOL.


Yes.

Let them screw you and lawyer up.

As for Overtime. Call your labor Board.

Yes I signed something saying I agree with my wage and the 40 hr guarantee but I haven't signed anything about the changes.

If they made a change and notified you you assented to the change by not quitting.

Depending on how far OP wants ot take it that's a question for a jury.