Brother Dixson might be able to tell us of that.
My guess is the original Pods did not allow for the carriage of underslung loads.
The Pods were re-designed so that could be done but the Army did not purchase any of the improved Pods.
The Chinook was designed (as was the CH-53) to be able to use its cargo hook while at the same time carrying passengers and other internal cargo.
Thus, making it far more effective in combat operations.
The CH-54 then reverted to "heavy lifts".
The early A Model Chinooks could not lift the standard 155mm Howitzer which the crane could handle.
The 105MM Howitzers were easily carried by the Chinook....to include the Gun Crew internally and what was called an A-22 Bag of Projectiles fuzes, and. powder for the Gun.
Later models of the Chinook were able to lift the improved 155's that were much lighter than the originals.
An example......While waiting for access to a refueling point at a place called Tay Ninh.....we learned of a stripped down M-113 ACAV that was stuck just outside the Perimeter....that had struck a large Mine and had been disabled.
It was waiting for a CH-54 to arrive to lift it a short distance into a secure area inside the perimeter.
As we were down to about 20 minutes of fuel...and were flying a CH-47A with upgraded engines....we decided to give it a try so we could "show up" the Crane guys.
It was a max weight lift....but one done with no problem....lift to a hover....move forward a couple of hundred yards....and set it down.
We did the lift and went on about our business.
I suppose we could have gotten word back to the Crane Unit but knowing upon their arrival they would be making inquiries all around about just where this stranded ACAV was.....to be told "Oh...never mind...some Chinook has already moved that!" would be a proper finger in their eye!
My recollection of the Crane Units is they were Prima Donna's and seemed to be a bunch of whiners.....always complaining their loads were too heavy....too light....not rigged correctly....and sorry but we must be off back home as it is Steak night and we do not wish to be late for dinner.