tranny problems???

I have a 98 olds bravada with 130k miles, and as of last week the suv acts like it has been slipping in and out of 4th/od. It happens when driving down the highway at about 55-60. The rpms jump up and then back down, as if its slipping out of overdrive. It happens over and over until ya step on it and make it drop down or make sure there is a good load on the suv, such as going up a hill or trying to accelerate. Any ideas would be a great help.

I think the 98 has electronic shifting, which i don't know much about, but until you find the problem downshift to drive or third gear to keep from burning out the 3-4 clutches right now. hopefully someone will post with more info.

thanks, any other ideas???

Any Check Engine lights? Looks like a "Trans. Component Slipping" code should be present.
You can get a free DTC code check at some chain type auto parts stores...give some a call.
How long since a trans. fluid and filter change?

the check engine light hasnt came one yet. the only gear that it seems to slip in when its in 4th/od. I think the last time the tranny was flushed was about 90k, it may be time to do that again, couldnt hurt atl

You also might check to see if your brakelights are coming on during this event. The brakelight switch wiring also de-activates the torque converter clutch when you hit the brakes, which would seem like a slippage during normal driving..