Jerky Wipers 2000 Jeep Cherokee Sport

I talked about this problem with winshield wipers awhile back.

At times they were jerky and bouncing looked like on winshield when running.

My first suspicion was bad wiper blades and they were in bad shape.
Both seemed to loose on wiper arms so I replaced both . This did help
some .

Today I was out in rainy weather and they got jerky again. At my next stop I got out of vehicle and felt the main wiper arms to see how good they were mounted on Knurled mount posts. To my surprise 'I could move both wipers up and down on knurled mounting posts. I realized then that this was the problem. Turns out that the wiper transmission has got to be replaced to fix it.
Oh we,ll thought I,d tell you guys this resolved problem I had.

Check the bushings on the linkage from the wiper motor to the wiper arms...