Your limit will likely be the receiver or payload. Verify your as equipped payload per this sticker on your driver's door post:
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Your payload is probably in the 1500 pound range as equipped. If you actually have 1000 pounds of people and cargo in the SUV, your max tongue weight is only 400-500 pounds, which means about a 3000 pound dry RV.
You should also verify yours has the HD towing package with 3.42 axle and engine/trans coolers. Locate the sticker in the glove box and look for KL5 for GM's HD trailering package. KNP is the Trans cooler and KC4 the engine oil cooler.
You are he first owner of a 2015 GM SUV. Can you please look at the receiver for a sticker like this one? What are your limits?
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