2005 Mountaineer transmission downshifting

[AlexCalderon02]

My 2005 mountaineer has developed this intermittent issue lately with the transmission and it's becoming a more constant problem. Basically when I'm cruising at a constant speed the transmission tends to downshift and upshifts sparatically. I drive around 20 miles to work on the highway everyday, and what's odd is the drive there never has this issue but when I'm coming home from work it does it the whole way home. I don't think heat has any relation to this as it's done it from the winter to the summer. The transmission feels fantastic too, but I have noticed the solenoid packs are likely due for replacement as when I change drive modes there is a jolt. My mountaineer is a 4.6l V8, and just crossed 200k miles yesterday!

Fluid has NEVER been changed in this transmission to my knowledge. I'm thinking of doing fluid flush and solenoid replacement, but I'm not sure if that is going to solve the issue

 

[Number4]

I’m at 300k+ on original trans and fluid. You could do a filter change and what ever fluid comes out, but not a flush. The crap in the fluid at this point is part of your friction, as I understand.

Most transmission shops will do a free diagnostic.

 

[AlexCalderon02]

I’m at 300k+ on original trans and fluid. You could do a filter change and what ever fluid comes out, but not a flush. The crap in the fluid at this point is part of your friction, as I understand.

Most transmission shops will do a free diagnostic.

That gives me some reassurance that my transmission isn't a fluke lasting that long. I always see people shying away the 3rd gen because of transmission issues.

And yeah, I've heard that before with the whole fluid situation. Unfortunately doing the solenoid packs requires dropping the pan and thus the fluid. And since our trucks don't have a dipstick on the transmission, I also don't have a way of knowing if I'm low on fluid (does mercon v burn overtime?), unless I'm wrong there. But if I go through with doing this job I will likely store the original fluid that comes out in case new issues arise with fresh fluid.

Good to know about the trans shops, I might call a few around me and see what they say