My Disco has had a hesitation problem for quite some time. When I would drive on the highway about 60 to 70 MPH it would hesitate or the engine would reduce power which I think it is supposed to do when the computer detects and overspeed. Anyway it only did it once in a while so I lived with it until one day I was driving and when it did it the speedometer dropped to zero. It only lasted a couple seconds but I figured was time to deal with it. I read that you can rebuild thembut the sucess rate isn't that high so I decided to drop the coin on a new one. I bought it from Rovah Farms, Trevor was great to deal with, at $96. When I took the old one out I was glad I bought the replacement. It fell apart and had a lot of corrosion inside the housing. I believe if I had rebult it it wouldn't have lasted. So it runs fine now with no hesitating for about a month. Hope this helps anyone else having the same problem.

JB

 

That's not corrosion, it's grease mixed with shavings from the nylon bushings.

If you replace the bushing with a ball bearing, it'll never wear out.

However, the sensor uses a reed switch. If you get instances where the speedo drops to zero, it's probably the reed switch.