In high-stakes litigation, expert testimony is often the difference between liability and a defense verdict, but what happens when a key expert disappears on the eve of trial? In Diamond Hydraulics v. GAC Equipment, LLC, the Supreme Court of Texas confronted that question and delivered a clear message. While Texas Rule of Civil Procedure 193.6 imposes a demanding standard, it is not meant to produce unjust results.
Reversing both the trial court and court of appeals, the Court held that the exclusion of a substitute expert, after the original expert left the state and refused to testify, was an abuse of discretion. In doing so, the Court reaffirmed that "good cause" is a meaningful safety valve, not an empty promise.
The Background of the Case
The dispute arose from a failed crane cylinder. GAC Equipment, doing business as Austin Crane Service, retained Diamond Hydraulics to repair the component. When the cylinder later bent during a lift, each side blamed the other. Austin Crane sued for breach of contract and warranty, alleging defective repair.
Causation quickly became the centerpiece of the litigation. Both sides retained experts to analyze the metallurgical failure. Discovery was contentious and prolonged. Diamond did not gain access to inspect the cylinder until more than two years into the case.
The litigation timeline grew increasingly compressed. Both parties made late expert designations. The trial court permitted Austin Crane's untimely rebuttal expert designation, more than six hundred days after the deadlines, while denying Diamond a continuance to respond. Ultimately, trial was reset.
Then came the pivotal development. Shortly before the rescheduled trial, Diamond's expert left his employment, moved out of Texas, and refused to testify. Diamond acted quickly, seeking to substitute another engineer from the same firm who had participated in the underlying work and would offer identical opinions. The trial court denied the substitution as well as a request for continuance. Diamond proceeded to trial without a causation expert and lost. The court of appeals affirmed the lower court's decision. The Texas Supreme Court reversed.
Rule 193.6 and the Structure of Exclusion
Texas Rule of Civil Procedure 193.6 establishes a default rule of exclusion for untimely disclosed evidence, including expert testimony. Tex. R. Civ. P. 193.6(a). A party may overcome that exclusion by demonstrating either:
- Good cause for the failure; or
- Lack of unfair surprise of prejudice.
The burden rests on the party seeking admission. Tex. R. Civ. P. 193.6(b). Appellate review is deferential, requiring a showing that the trial court abused its discretion by acting arbitrarily or misapplying the law. Fort Brown Villas III Condo. Ass'n. v. Gillenwater, 285 S.W.3d 879, 881 (Tex. 2009); Abuse of discretion is established when a court acts "arbitrarily and unreasonably or misapplying the law to the established facts of the case." Huynh v. Blanchard, 694 S.W.3d 648, 674 (Tex. 2024).
The Court's opinion situates Rule 193.6 within its historical lineage, tracing it back to former Rule 215(5) and the Court's effort in Alvarado v. Farah Manufacturing Co., 830 S.W.2d 911 (Tex. 1992), to curb inconsistent application of procedural rules. While Rule 193.6 added a second pathway for admission, lack of surprise, it preserved the rigor of the "good cause" requirement.
Good Cause: Demanding, Not Impossible
The Court emphasized a critical point. The good cause standard is strict, but not insurmountable. It must be applied in a way that preserves its purpose, preventing trial by ambush. It was never meant to serve as a mechanical exclusion in which courts are forced to disregard the circumstances of each case. The court identified four factors demonstrating that Diamond met its burden.
- Circumstances Beyond the Party's Control: The expert's sudden relocation and refusal to testify were outside Diamond's control. Once he left Texas, he was beyond subpoena range. This was not a case of missed deadlines or strategic delay; it was an unforeseen disruption.
- Diligent, Good Faith Efforts: Diamond did not sit idle. It promptly notified opposing counsel, attempted to secure the expert's participation, and moved to substitute a replacement with identical opinions. The Court contrasted this conduct with the type of carelessness that fails to establish good cause, citing Clark v. Trailways, Inc., 774 S.W.2d 644, 647, for the proposition that good faith efforts support a finding of good cause.
- Centrality of the Expert Testimony: Causation was the core issue in the case, requiring technical, metallurgical analysis. Without expert testimony, Diamond was effectively stripped of its ability to present a defense. The Court underscored that this was not a peripheral evidentiary matter, but rather was dispositive.
- Arbitrary and Unequal Treatment: Most strikingly, the Court found that the trial court acted arbitrarily by allowing Austin Crane's late expert designation while denying Diamond's. The disparate treatment lacked a principled explanation. As the Court put it, it could find no reason "why sauce for the goose couldn't be sauce for the gander." the inconsistency independently supported a finding of abuse of discretion under Huynh.
Rejecting Formalism and Strategic Hindsight
Austin Crane advanced several arguments that the Court rejected as overly formalistic. First, it challenged whether the original expert was truly unavailable. The court held that Rule 193.6 permits consideration of the entire record, not just affidavits, and that the record clearly established the expert's refusal to testify. See Tex. R.Civ. P. 193.6(b); Jackson v. Takara, 675 S.W.3d. 1,6.
Second, it argued Diamond should have anticipated the problem by developing deposition testimony. The Court declined to impose such a requirement, noting that lawyers do not ordinarily examine their own experts in deposition and are not required to predict future unavailability. Finally, Austin Crane urged the substitution would cause unfair prejudice. The court did not reach that issue, emphasizing that Rule 193.6 is disjunctive. Once good cause is established, the analysis ends.
A Return to Balance
The Court's decision restores balance to Rule 193.6. It reaffirms that procedural rules serve the truth-seeking function of litigation, not the other way around. While the rule guards against gamesmanship and surprise, it does not require courts to ignore reality when unforeseen circumstances disrupt trial preparation.
At the same time, the opinion does not dilute the rule's rigor. The Court was careful to distinguish this case from those involving inattentive counsel or tactical delay. The message is not that late designations will be freely excused, but that courts must engage in a meaningful, fact-sensitive inquiry.
Key Takeaways
- Good cause remains a high bar, but it is not unreachable. Courts must apply it with discipline, not rigidity.
- Unforeseeable witness unavailability can satisfy good cause, particularly when the party acts promptly and in good faith.
- The importance of the excluded evidence matters. Where expert testimony is central, exclusion carries greater consequences.
- Consistency in trial court rulings is critical. Disparate treatment of similar conduct may itself constitute an abuse of discretion.
- Rule 193.6 is disjunctive. A showing of good cause alone permits admission, regardless of prejudice arguments.
Conclusion
Diamond Hydraulics is reminder that procedural rules, while essential, must be applied in service of justice. The court resisted a mechanical application of Rule 193.6 that would have rewarded happenstance and punished diligence. In doing so, it reinforced a principle that resonates beyond Texas. Fairness in litigation depends not just on rules, but on their reasoned application. Where an expert vanishes and a party does everything right, the law does not demand forfeiture. It demands judgment.
