Synthetic Trans Fluid

[Ed_Manifold]

I had Transynd synthetic oil installed in my 3000 Allison transmission at 34,911 miles on 2/12/15. My understanding was with the synthetic oil installed that I would not need to service again until approx. 100,000 miles. The mechanic that is now doing some of my service work told me that I still needed to service the transmission yearly. I now have 47,407 miles. I am concerned that I have not been servicing my transmission correctly. Please help me understand what the correct service requirements are?

[Ed_Manifold]

Thank-you for your input.

[wolfe10]

Suspect somewhere between every year and every 10+ years (based on your miles/yr) is the correct answer.

Were it me, a fluid and filters change every 5 years with your few miles per year should be fine as long as not other issues (like coolant in fluid, fluid discoloration, etc).

[gbopp]

Change your transmission fluid on a regular basis. It's cheap insurance.

[jdc1]

Tiny particles can clog the valves. The filter cannot catch it all. While synthetic fluid can withstand higher temperatures, it cannot do anything different when it comes to these particles.

[Lwiddis]

What does the manufacturer, Allison, recommend?
Why wouldn’t you follow Allison’s advice?