Speedometer issues

[CumminsNoah]

1994 Dodge Ram 2500.Cummins, 5speed,
Speedometer will bounce around 0-40 mph.
then peg at 40mph regardless of speed once I hit about 25mph. Will drop and bounce around randomly.
Replace sensor at the transmission with no change.
Any ideas would be helpful,
Thanks

 

[GAmes]

When you pulled the sender off did you check the little driveshaft for the gear? I had the same issue and after completely disassembling the housing and sender I found the broken shaft. When you reinstall it be sure to clock the case correctly.