I recently changed the ATF & filter in our 07 Yukon Denali. I took a sample with a JG Lubricant Services used oil analysis kit. They use Polaris Laboratories. Sent it in and 5 working days later here are the results. This is the same fluid and filter as sample result #1.
Lab flagged the viscosity of 5.6, so I called Tom Johnson of JG Lubricant Services. Tom is co-owner of JG Lubricants. He spent 30 yrs with GM/Allison as a fluids engineer developing the TES295 spec, etc. He said when viscosity gets to 5.5 they recommend changing the fluid. When viscosity gets to 5.0 bushings etc start to wear. So my timing this fluid/filter change worked out good. Not too early, not too late.
Tranny has 174k miles since new. 43k miles ago, while doing the engine rear main seal job, I replaced the original torque converter as a preventative mx item. That was the last time I changed all the fluid and the filter.
Lab flagged the viscosity of 5.6, so I called Tom Johnson of JG Lubricant Services. Tom is co-owner of JG Lubricants. He spent 30 yrs with GM/Allison as a fluids engineer developing the TES295 spec, etc. He said when viscosity gets to 5.5 they recommend changing the fluid. When viscosity gets to 5.0 bushings etc start to wear. So my timing this fluid/filter change worked out good. Not too early, not too late.
Tranny has 174k miles since new. 43k miles ago, while doing the engine rear main seal job, I replaced the original torque converter as a preventative mx item. That was the last time I changed all the fluid and the filter.