Speed "jumps" 5-8 mph instead of smooth sweep. Any one ever heard of this?

[Blacksdieselhp]

The truck is an 06 megacab. It did have bd twins, dual cp-3's, built trans, tst and bullydog. Now the truck is back to stock besides a new Goerend trans and a Smarty. But the speedometer acted up with all the mods, and still does the same thing. It does it at all speeds and when at a stop, it doesn't go all the way to zero. It stays around 5mph when sitting still. And while moving it will jump 5-8 mph. Like if your cruising at 75 mph and accelerate to 80, it won't gradually go up to 80 in 1 mph incerments, it looks like its stuck on 75 then will jump to 80 all of the sudden. And slowing down, if at 80mph, you may slow down 15-20 mph before it will move off of 80. Anybody know what may cause this? I thought it might have been some of the mods that were done, but it wasn't.

 

[rbattelle]

Sounds to me like a problem with the gauge itself. Something sticky in the movement.

If so, I wouldn't think it's related to any of the modifications. Unfortunately, I don't think it's replaceable by itself - you have to replace the entire cluster.

It might be enough to dismantle it and lubricate it with clock oil.

Ryan