If grease is seen pushing past the trunnion seals on three of the four crosses during universal joint maintenance, what action is indicated?

• A. The cross should be discarded and replaced.
• B. Increase grease application to all crosses.
• C. Seal all seals and continue.
• D. One bearing on the cross might not be receiving lubricant and should be removed for proper servicing.

Answer: (D)

When grease is seen forcing past the trunnion seals in a universal joint, it points to a lubrication issue inside the joint rather than just a seal leak. If three of the four crosses show grease migrating past their seals, the most likely problem is that one bearing path within a single cross isn’t being properly lubricated. That starving cross disrupts the lubrication distribution, and the others may push grease past their seals under pressure as a result.

The correct action is to remove the specific cross suspected of not receiving lubricant to inspect and service it fully. You’ll want to check the bearing surfaces and bore for wear, inspect or replace seals, clean out any contamination, repack with proper grease, and ensure the grease passages are clear. After servicing that cross, reinstall and recheck the joint to confirm even lubrication and seal performance.

Discarding the cross or simply adding more grease to the others doesn’t address the blocked or worn lubrication path, and sealing and continuing would allow the underlying issue to persist.