Help with JCB 214s hydraulic line question

Short answer: those larger rear quick disconnects are very likely auxiliary hydraulics for a rear/backhoe attachment circuit—commonly a hydraulic thumb, hydraulic breaker, auger, or other 2-line attachment, not something unique to the Amulet thumb. Since your thumb “doesn’t use extra lines,” the couplers may simply be plumbed-in aux lines that were added or left on the machine, or they may be for a different attachment function than the thumb itself.

On the 39 gpm / 3000 psi point: I would not assume that full flow is available at the backhoe couplers all at once. On many backhoes that spec is effectively combined pump flow, while implement circuits and auxiliary circuits may be split, diverted, or limited by the loader/backhoe valve stack and machine plumbing. I can’t verify the exact JCB 214S hydraulic layout from the info provided, and I don’t want to guess.

For your 36 gpm snowblower, check these in order:

1. Machine PIN / serial number from the frame, not the engine serial.
2. The hydraulic schematic for that exact 214S.
3. Whether the rear couplers are on a dedicated high-flow aux circuit or just a standard auxiliary line.
4. Coupler size and hose size — bigger couplers do not automatically mean more flow.
5. Whether the machine can provide continuous 36 gpm at the attachment with acceptable case drain / pressure limits.

If you send the full 17-character PIN or a photo of the couplers/valve area, I can help narrow down what those lines are. For anything safety-critical like flow/pressure setup, verify against the official JCB manual before running the blower.