I have a 2007 Screw 4X4 that just turned 14,000 on the odometer. Since I have a company car the truck can sometimes sit for 2-3 weeks without moving. I switched engine oil to synthetic and change it once a year, every summer. Its coming up on four years now and I still have the original ATF fluid in it. The truck is used as a family car basically, I never haul or tow anything besides my wifes *** or a run to the dump. Most people say to change at 30,000 with normal use, so should I wait another possible 3-4 years at this rate or should I change it regularly at shorter intervals? If shorter, how often?

 

I'd stick to the 30k oil changes. It's not like trans oil gets contaminated with combustion products like engine oil does.

 

I agree.
If you change it any sooner then 30,000 miles you;ll just be wasting money.

Phil