Hey everyone, newbe member here. I just purchased a 2012 Cadillac CTS 4 with a 3.6 liter V6 and all wheel drive. The car has 60k miles with no service record so I intend to replace every lubricant in the car. I intend to keep it indefinitely and my driving habits are a bit more spirited than the average Cadillac owner. These are my questions:
The owners manual calls for 5W-30 semi-synthetic. I searched for common issues with this engine and found the timing chains tend to stretch causing various trouble codes to light up and the only fix is to tear it down and replace the chains and tensioners. I live in South Texas where the heat averages 100 deg F in the summer. Should I go with a higher viscosity such as 10W-30 or 10W-40 to provide more shock load cushioning on the chain rollers and preserve idle oil pressure? The owners manual states to stick with the recommended weights (of course it always says that but IMO the engineers aren't concerned with the vehicle past the warranty expiration). Should I flush it before the change?
Transmission: Dexron VI I've ordered 6 bottles of Transtar ATF. Their website indicates this company manufactures GM labeled fluids.https://www.walmart.com/ip/ATF-Flui...-LV-SP-IV-SPH-IV-WS-FZ-ZF6-ZF8/126963350
Front and read differentials: 75W-90 with 4 oz of limited slip additive. Ordered Mobile1 LS 75W-90 and no additive.
Transfer Case: This is my biggest question. Owner manual indicates Transfer Case Fluid GM PN 88861800
I called Mobile's customer support number, was transferred to a higher level of support, and the agent stated they list no fluid for this application. I found a topic on this board with a similar year and model vehicle and the final answer was either straight ATF or motorcycle engine oil as gear lube kills the carbon fiber clutch plates. If that suggestion holds am leaning towards a full synthetic H-D spec oil or just going with the factory fluid. I want to make sure the internals last.
I have bottles of Lucas Transmission Fix and Lucas Oil Stabilizer on hand. Should I use these or leave them out?
Thanks in advance. I've had success in the past keeping older vehicles running by going with my intuition and past experience as a service tech on vintage imports and dealership vehicles but this is the most complex vehicle I've tinkered with.