Kurt writes:

Dear Sajeev,

I’m writing about if/when/how to change the transmission fluid in modern automobiles. It’s been my experience when changing the fluid on a vehicle with > 100,000 miles and original tranny, the odds of trans problems within 5,000 miles rise dramatically. The consensus on the interwebs is this was true for older cars, but not necessarily modern vehicles using synthetic fluid. First my history…I’m only listing the cars where I actually changed the fluid. 89 Suburu GL – Fluid Changed at 120,000, total trans failure at 125k. 94 Chevy S10 blazer, trans fluid change at 115k, trans failure at 123k. Current: 2006 Honda Odyssey – Trans Fluid Change at 95K, Torque Converter starting to go out at 100K (yeah, I know this is a weak spot on this vehicle regardless) – wondering if I should change out the rest of the fluid before having someone look at the torque converter?. Additionally what to do about my 2003 Chevy Trailblazer LS (2wd) …..145k, original transmission, original owner, no trans fluid changes ever. The quick lube joint says fluid color is off – looks good enough to me though. I’d like to keep the truck a few more years due to the blood sweat and tears already invested in repairs.

I’ve read that Trans Fluid power flushes can cause more harm than good, and a standard fluid change only swaps a % of the fluid – normally needing 3 of those to get a full fluid swap. Add the twist of certain vehicles needing “special” fluid such as Hondas and it’s hard to say if my failures are due to improper technique by improperly trained quick lube employees, improper fluid, or if changing the fluid isn’t really needed! I always say “I’ll change the trans fluid when the trans fails”. I’m a mild wrench head, some blacked fingernails to prove it ….if my setup allowed it I’d love to change my own fluid – no one cares as much as the owner. However I stopped changing my own fluids after an Exxon Valdez-like accident on my driveway. Any advice on this topic? (Read More…)