House and Senate Republican leaders were hoping to be united on tax reform to avoid a repeat of this summer’s ObamaCare repeal debacle.

But that plan will be put to the test as the Senate prepares to unveil its version of the tax bill, which reportedly could eliminate popular state and local tax deductions and include additional changes from the House bill. Any big differences between the competing bills could slow or sideline the legislation, though leaders are aiming for swift passage.

“We did things differently this time because of the health care experience,” House Speaker Paul Ryan told Fox News on Sunday. “We worked with the Senate ahead of time, from the summer on, to put this bill together.”

Senate Republican leaders reportedly are considering the elimination of the state-and-local tax deductions, while the House is pushing only for a partial rollback and still deliberating in committee.

The Washington Post also reports that the bill might delay until 2019 a proposed $845 billion corporate tax cut, considering the House plan to reduce the rate from 35 percent to 20 percent starting next year would reduce federal revenue by $108 billion in the first year and add $1.5 trillion to the deficit over the next 10 years,

Republicans can pass the legislation with a simple, 51-vote majority if it doesn’t increase the deficit after 10 years. However, they have just 52 senators in the chamber, giving them only the slightest margin for defections.

The Senate made several failed attempts this past summer to use a similar budget-related procedure to repeal and replace ObamaCare with a 51-vote majority, denying President Trump a major legislative victory.

The tax-writing House Ways and Means Committee has been “marking up” the House GOP bill this week and could finish as early as Thursday.

The Senate will not unveil its version until the House committee completes its work, sources on Wednesday told Fox News.

Trump has gone back and forth about when he wants the bill on his desk, publicly setting a Christmas or New Year’s deadline, then purportedly giving no deadline to Senate Republicans in a closed-door, Capitol Hill meeting before leaving for Asia.

Ryan on Wednesday acknowledged that the House bill includes some provisions that members don’t like but are needed to conform to Senate rules.

They include ending in five years a tax credit for so-called “non-child dependent care,” which helps Americans taking care of their parents.

“We unfortunately have to live by their rules,” Ryan said at a Washington Examiner forum. “But these are sunsets that we don’t believe will ever occur.”

Politico reported Wednesday that the Senate’s bill, being written in the chamber’s Finance Committee, might not fully repeal the estate tax, like the House version is expected to do.

A proposal to eliminate the ObamaCare individual mandate to save the federal government billions of dollars is not expected to appear in the final House version but could be in the Senate's, considering GOP senators like Tom Cotton, Arkansas, have championed the concept.

Still, Ryan recommitted Wednesday to an earlier promise to pass the bill by Thanksgiving.

“We are on track to pass this … the Saturday before Thanksgiving,” he said.

Fox News' Joseph Weber and Chad Pergram contributed to this report.