* Crude futures end higher in choppy, thin volume trade * Brent/U.S. crude spread seesaws, ends wider * Valero restarts McKee, Texas refinery crude unit NEW YORK, May 6 (Reuters) - U.S. cash crude differentialswere mixed on Monday, with trades done in wide ranges as thetransatlantic spread between Brent and U.S. crude futuresnarrowed before ending wider. Crude futures rose in choppy trade on Monday with Brentsettling more than 1 percent higher as Israeli air strikes onSyria fueled concerns about potential disruptions to Middle Eastsupplies. Gains were curbed during the session by worry about theglobal economy and curbed demand from oil if the economysputters. In the U.S. cash crude market, Light Louisiana Sweet for June delivery traded at $11.15, $11.20 and $11.25 above theU.S. June crude futures contract, also known by itsbenchmark crude grade West Texas Intermediate (WTI). WTI is the U.S. light, sweet crude contract's benchmarkgrade deliverable at Cushing, Oklahoma. Those LLS differentials were within Friday's range of tradescompleted at $10.70, $10.75, $11.15 and $11.30 above thebenchmark. A Gulf of Mexico-produced grade, Mars sour , traded at$6.60 to $7.00 above the benchmark futures for June barrels,only a slightly weaker range after trading Friday at $6.70,$7.00 and $7.20 above the benchmark. A trade for Mars July barrels was completed at $6.00 overthe benchmark futures. Southern Green Canyon traded at $5.50 over thebenchmark, after Friday's trades at $5.60 and $6.85 over. Expectations that maintenance this month at a BP gasprocessing plant in Pascagoula, Mississippi, will shut in a someGulf of Mexico oil production caused most differentials tostrengthen on Thursday. Also supportive to differentials recently were expectationsfor higher demand from refiners returning units from seasonalmaintenance ahead of the U.S. summer driving season, traders andbrokers said. On Monday, June barrels of Thunder Horse crude, froma BP production platform in Gulf of Mexico, had offers pegged at$9.50 over the benchmark, weaker after offers seen on Friday at$10.50 over the benchmark. Thunder Horse was seen traded at $9.90 over on Wednesday. MIDLAND GRADES Crude grades in West Texas remained supported by the restartof a 156,000-barrel per day crude distillation unit at ValeroEnergy Corp's McKee, Texas, refinery after a turnaround,according to traders and brokers. Valero said on Monday the crude unit has restarted and wasmoving to planned production levels. Recently increased pipeline capacity from the Midland, Texasregion to the U.S. Gulf Coast's refineries has also helpedsupport differentials, traders said. West Texas Intermediate crude at Midland traded from35 to 65 cents over benchmark futures, a wide range reflectingthe narrowing and then widening of the Brent/WTI spread onMonday. Midland traded on Friday at 60 and 65 cents over benchmarkfutures, after Thursday's trades at 35 and 40 cents over. West Texas Sour crude, also at Midland, traded at 60cents over the benchmark, slightly weaker after trading onFriday at 65 cents over the benchmark. BRENT/WTI SPREAD Brent's premium to U.S. crude ended at $9.30 abarrel on Monday based on June contract settlements, higherafter ending at $8.58 on Friday. The premium was as low as $8.18 on Monday, the narrowest thespread has been since it was at $8.01 intraday on June 21, 2012. Usually the wider the arbitrage, the more supportive forU.S. cash crude differentials and a narrower spread oftenpressures differentials. This holds especially for sweet gradesthat are priced in line with other global waterborne crudes suchas Brent. CRUDE FUTURES PUSH HIGHER Brent June crude rose $1.27, or 1.22 percent, tosettle at $105.46 a barrel, having traded from $103.89 to$105.54. U.S. June crude rose 55 cents, or 0.58 percent, tosettle at $96.16 a barrel, having traded from $94.85 to $97.17. (Reporting by Robert Gibbonsm editing by G Crosse)