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I have a 2000 Excursion V-10. It has 88,000 miles on it. When driving in traffic and maintaining a speed range of 40-50 MPH it feels like rough shifting when slowing and then accelerating. This is very intermittent right now and will not do it when accelerating quickly to speeds above 50MPH or slowing from speeds above 50MPH. It only does it when maintaining the 40-50 MPH range. I keep thinking it is a transmission problem but it feels like the roughness is coming from the rear end. I looked underneath to see if there were any leaks around the transmission. There are no leaks and fluid level checks good. I did notice a leak on the rear differential, which is coming from the pinion seal area. Could these two be related? Also does this year use any type of computer to control the transmission?
I had almost the identical issue even with the tail of the transmission weeping a bit of fluid. Turned out to be a bad COP causing a miss at that speed. Lucky caught it pre-purchase and dealer had it fixed for me. Runs great now...
try cleaning the speed sensor on top of the rear differential.
Comes out very easy. Wipe it down with a rag.
My v10 started shifting very rough at some point and even threw a code about the speed sensor. Cleaned it off and it never returned and shifted great after that.
Might not be the cause but it's an easy and cheap thing to try.
Thanks for the info. I think I am going to start with the speed sensor mentioned by Az_r2di. I don’t remember seeing it but I assume it is easy to identify. My only concern is the amount of rust on the rear differential. I was going to check the fluid level when I discovered the leak but was very concerned with the amount of rust on the fill plug. I didn’t want to damage it and left it alone. My plan is to start soaking both the fill plug and sensor in PB Blaster over the next few days and let it really soak in. If anyone has some techniques that may work I am all ears.
You will see it when you look for it. It is on top of the rear diff housing on the inside.
Make sure the area around the plug is clean so no junk will fall inside the housing when you remove the sensor.
Let us know how it works out.