venture transmission problem

[gwm]

I have a 2000 venture. 175,000 km,s. I've never changed tranny fluid.
Since a week ago, it won't change into 3rd gear. Will fluid and filter replacement correct this?

[cdru]

Remote possibly, but not likely. It really depends on what is not working. If it's a valve that is sticking, it's a possiblity. But if it's a worn valve that's leaking or band or clutch plate that's shot, no amount of fluid, filter, or addatives will bring it back.

[gls02]

You have never changed the fluid or the filter, but have you checked the transmission fluid level? I don't know if changing the fluid/filter will correct your problem, but I once had a transmission that didn't want to shift gears (AMC Pacer) and just replacing the transmission fluid fixed it.

If it isn't throwing out any codes I would give it a try and change the fluid/filter and see what happens.