UPDATED Washington: The Army has pushed its iconic Humvee combat truck as far as it can go and needs to press ahead with the Joint Tactical Light Vehicle.

The Army cannot load any more armor, communications equipment or other next-generation gear onto the Humvee, according to Lt. Gen Robert Lennox, chief of the Army office in charge of funding service programs.

The service is pursuing multimillion-dollar effort to revamp the Humvee. But some have argued the Army can save millions if they just used upgraded Humvees to do the job of the JLTV. “I do not think we can,” Lennox told me yesterday when I asked if the Army could use the Humvee to replace the JLTV.

The upgraded Humvees were designed to supplement, not replace, the JLTV, Lennox explained. The Army would have to add a slew of additional upgrades to get the Humvee on par with the JLTV, he added.

The problem is the Army has already “hit the max capacity” on what it can do on the truck, as part of its ongoing Humvee recapitalization plan, Lennox said. Tacking on more equipment onto a combat vehicle that has been in service since 1989 is something the Army cannot afford to do, he said.

That said, the Army must press ahead with its plan to build the new JLTV, the three-star general added. Testifying before the House Armed Services tactical air and land subpanel yesterday, Lennox and the Army’s deputy acquisition chief Lt. Gen Bill Phillips dismissed the notion of upgraded Humvees replacing JLTVs.

Instead, service leaders have been focused on “getting the requirements right” for both programs and educating lawmakers on why the Army needs both vehicles, both men told the subcommittee.

Today, Army Vice Chief of Staff Gen. Peter Chiarelli said the JLTV was “absolutely critical” to the service arsenal. “It is absolutely essential we be allowed to continue . . . that critical work,” the four-star general told the House Armed Services readiness subcommittee this morning.

But recent Army efforts to get requirements right for the JLTV is exactly why some are wondering whether a retooled Humvee can do the job cheaper.

The Army and the Marine Corps decided to drop several key features on the JLTV earlier this month, to get the truck’s total costs down. The Army now claims it can buy the toned-down JLTV for roughly $270,000 per truck. Previous cost estimates have priced the JLTV at $350,000 per copy.

Trimming key features from the JLTV has made the vehicle virtually indistinguishable from the upgraded Humvee, Loren Thompson, defense analyst with the Lexington Institute and member of Breaking Defense’s Board of Contributors, claims.

The only difference between the proposed JLTV and the updated Humvee is cost, Thompson argues. That message has already begun to resonate in the halls of Congress. Senate appropriators opted to kill the JLTV in their version of the 2012 defense budget. Their House counterparts took $50 million from the program in their draft of the legislation.

In the end, growing budget pressures on the Army may force the service to consider using Humvees as a JLTV replacement, Lennox admitted. But until then, swapping JLTVs for Humvees is a question “we have not asked,” he said.