B767 pilot reported a gear in transit indication with no EICAS messages during cruise. The flight crew returned to departure airport and made an overweight landing.

Narrative

At cruise prior to ZZZ Entry; we got a gear in transit indication with no EICAS msgs. Then we got a Gear Disagree EICAS msg with a nose gear up; left gear DN and locked (green) and right gear in transit displayed. We all agreed we didn't want to cross the ocean with these indications displayed and agreed to return back to ZZZ. Captain handed the plane to me after [requesting priority handling]; and I assumed PF (Pilot Flying) duties along with ATC communications. Captain then called the F/A's (Flight Attendants) and advised them we were returning to ZZZ due to a malfunction. Captain and jumpseater worked through some checklists. Captain then talked to Dispatch. We descended to 10;000 and held over ZZZZZ; consulted the Fuel Dump Checklist and dumped all fuel remaining in Center Tank. We held at ZZZZZ at 265 kts. as we were very heavy at that time. Captain talked to F/A's once again and advised passengers we were returning to ZZZ. We tried calling Dispatch again; but for some reason were unsuccessful. We consulted Performance in Flight Manual and decided to land on XXR in ZZZ. We also consulted the Diversion Guide in the FOM. We shot an RNAV GPS XXR approach into ZZZ with windy conditions. We got numerous other EICAS msgs on short final that were apparently associated with original malfunction; and decided to continue. We landed XXR and I noticed we didn't have any Reversers and advised the Captain as such. We then exited the Runway; told ATC we no longer had [a situation) and taxied back to the Gate. We did parking checklist and then Maintenance came on and we consulted with them. We then went to the hotel. Captain exercised his overall command of the situation very well and we also interacted really well as a crew.