The speedometer on my 2002 Montana stopped working and it started to shift irregularly. It doesn't shift at the right time and lurches the van when it does shift.

The service and repair manual will help you to locate and fix the problem on your own and you will get the manual from the given link http://toolsnyou.com/

abs not going to be the cause...possible passlock security system problem....does the security light flash rapidly when it wont start? it is common for the security system to act up on these vehicles

the speedometer sensor is located at the rare end the the transmission

Sounds like an electrical issue likely in the harness that runs from the body to the gas tank or close to the ECM and the wiring may be rubbing against the body close to the ECM and shorting out. Look for lumps in the wires or green corroded connectors.

is it a such thing as a floater tank being on the montana van

that and there is a plug on the side or top of the trans that might be un done as well

if it was my guess I would check the connection make sure all are connecting. I also worked on a older van that had day time running lights and its activated by a sensor that reads the light when it stops working the interior lights wouldnt come on same as radio so hope this might help.

Its most likely related. Vehicle speed sensor is bad

This has happened on our van multiple times. Through some internet searches I have found a solution that works.

Go to your van and, with the ignition off, press and hold the trip reset button. You will see 'Sof' and perhaps some diagnostic test numbers will show up on odometer; the unit will perform a self-test, and the system will do a reset and should it should operate normally.

Cheers!

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