When I get over 55mph it seems tranny not shifting into 4th gear. Been doing some googling and searching. Some say might be a solenoid.
Has anyone hear had this problem and fixed it?
Any suggestions appreciated.

 

got a check engine light on? please post the codes. im sure you checked the fluid level and have been changing the trans fluid and filters regularly right?

 

Fluid looks fine. No CEL codes.

 

does the cel light work? i cant see i not shifting gears and not tripping something in the pcm or tcm

 

I used a code reader and no codes.

 

then its time to take it to the shop. codes point you in a direction on where to start. if the fluids are good and filters have been changed and no shifting or codes, there is no way of knowing where to start for the average guy. at that point its time for the trains mechs and shop to take over

 

yep. I'm over my head here.

 

please let us know what you find out

 

Just going over some of my old threads and noticed I never gave the final resolution on a couple of them. I hate when people do that, especially when I'm googling, and someone posts a similar problem but never post how they fixed it.
Anyhow this thread is 7 years old but here's what I did. I ordered a new transmission solenoid pack. They're not cheap, couldn't find them online back then any cheaper than my local dealer.
I changed it myself. You have to remove tranny oil pan, drop the valve body (I think there were 6 bolts to do that. Then there were about 13 bolts to remove the solenoid pack from the valve body.
Here's a youtube video of guy changing it on a jeep cherokee, but looks to be the same procedure.