Home › Forums › Stay Dirty Lounge › Service and Repair Questions Answered Here › 2006 Sierra transmission lines › 2006 Sierra trany lines September 16, 2019 at 2:12 pm #894502 Charles HuppParticipant Anybody changed transmission lines on a 2006 GMC Sierra has external oil cooler and is 4wheel drive wondering how much I need to drop to gain access thanx