2003 ford explorer / Changed tires - two different brands / Now has jumpy acceleration?

I just changed out four Good Year Fortera tires for 2 GY Fortera and 2 Firestone. Afterward, most of the time upon using passing acceleration the truck's gear or brakes seemed jumpy. I can almost describe this like how the 4X4 feels like when it engages in low. I tried swapping the rear tires to the front and now the problem feels like its the opposite. Now acceleration is fine but when the truck slows down I feel the same jumpiness even awhirringg noise as if the truck were in slowing down in 4X4 low. I visually checked the ABS speed sensor on the front tires. Did not see one for the back. I'm guessing its located somewhere near the differential. What could the fix for this be?

Update: Pulled the ABS fuse, no joy, same problem plus had ABS light. Pulled 4X4 fuse (vbatt 2 & 1)#17 and #18, problem went away except of course for occasional flash of in-dash 4X4 high and low lights and ABS light. I haven't disconnected the differential ABS sensor if this at all is an ABS problem.