[Chicago610]

Hey all, I have a 2002 GMC Yukon XL, 5.3 liter, and I am the original owner. I have 166K on the motor and cannot remember if I have ever had the trans serviced. I am wondering if I should have it serviced now, and am worried that if I do will my trans adapt to the new fluids or should I leave well enough alone? Anyone out there have an '02 and when if ever has your trans gone. I love the truck, it was built right, thankfully, and have only had to replace the power steering and water pumps, and recently the catalytic converter. Thought?

 

[silveradotrailblazer]

Welcome to the club. GM recommeds a trans service at 100,000 miles. I do mine every 40,000-50,000 miles and I use a synthetic trans fluid. In your case I would find a shop with trans vaccuum pump and pump out ALL the old fluid and then drop the trans pan and change the filter. This cost more $$$ but it get ALL the old fluid out. Since your not sure about if the trans has been serviced I would do it this way. Some shops will try to talk you out of this because it is a pain for them to do it this way. Just find a shop that is willing to do it this way.