Question about 2009 Mercury Milan

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Speed sensor shaft transmission

My speedometer on my 2009 Milan keeps jumping up and transmission seems to slip. Any thoughts?

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Sorry you will have to consult the dealer for the services of the nerdy looking one with the laptop under his arm on this ,suspect a fault with electricals if this is a auto version ,well its a american so it must be a auto as they dont have proper instructors who can teach students how to drive a manual vehicle .Do love winding up my american cousins over this but the fact is its a 2009 model with more electronics than the apollo moon mission in 69

Posted on Oct 18, 2013


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Posted on Jan 02, 2017

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SOURCE: 1999 cougar automatic transmission slipping

At end of speedometer cable mounted on the transmission.

Posted on Jan 11, 2009

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SOURCE: My 2007 AWD Premier Milan has a whirring noise

wheel bearing !. jack up car , spin the wheel -should be no noise coming from the bearing. good luck.

Posted on Feb 23, 2010

  • 21873 Answers

SOURCE: p0701

The general definition is a problem with the trans control module.
The module could be faulty, or a problem with the wiring harness to the transmission.
You may want to check with the dealer or do some online research to see if there are specifics for the code on your model of car.

Posted on Sep 01, 2012

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1 Answer

2003 pontiac montana shifts hard from first to second around 4500 rpms, then sparacticly shifts around until i go faster, meanwhile the speedometer is jumping around from 10 to 20mph any thoughts??

Have you checked the transmission fluid?
May be a bad speed sensor. Just guessing, but if the transmission shifts based in part on speed, and the sensor I'd jumping around because it's bad, then it's possible the computer is shifting weird due to a bad input.

Apr 05, 2017 | Pontiac Cars & Trucks

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2005 pontiac bonneville transmission slips/ jumps. What could be the problem? The car has to warm up awhile before the problem starts. It sometimes jumps on acceleration or will slip.

Hard to say for sure without doing some testing , hooking up diagnostic tool . You have to understand the electronics an sensors involved in the control of the modern automatic transmission . Engine control sensors could cause erratic transmission operation also . TCC - torque converter clutch , input shaft speed sensors , output shaft speed sensors . Rather then replacing a bunch of parts that don't fix the problem , have a qualified repair shop ,at lest hook up thier diagnostic tool .

Mar 20, 2017 | Pontiac Cars & Trucks

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1999 jeep Cherokee classic. It will not go into 1st gear. It says it is the input speed sensor. Check gauge light comes on now. I replaced the alternator , input speed sensor and battery. Its over c

It says ? what says? the SCAN TOOL>?

non GRAND, (no engine stated, so fail there 1st)

my guess is you have a DTC and forgot to post that. why do that?

the DTC is covered in the FSM manual, and shows what is failing.

why not read the FSM and do what it says to do?

ill no attempt to read the FSM for you,. and that vague error.

why not log in to and stop guessing. at parts.

there is no reason to gue$$

my guess at he DTC,


or was it the P07xx series, all A/T errors.

P1xxx codes are factory code, got them? need all codes, not just 1 of many. and using a real scan tool not some POS autozoned junk (free)

p0500 is ASE jargon (best ) is VSS sensors.

vehicle speed sensor.

the transmission TCM monitors many inputs, and if they are bad

it can NOT shift, one such sensor is SPEED. MPH or VSS

the tail shaft all all 42RE transmission has a tail rpm sensor

when dead the cars speedometer goes dead, and the TCM

is at a lost to shift to 2nd gear, if speed is 0 all day.

a hopeless deal there.

if the battery voltage is not over 15v, its not overcharging, running.

99 is a nice jeep, id fix mine, ive had many.

the tranny has 2 speed sensors.

the front sensor does not do MPH, its just engine tranny input RPM

there are 3 RPM sensor

Engine, RPM called, CKP

tranny input sensor that tells the TCM true clutch slip at all time

and if the TCC works or not.

the tail shaft is the true speed sensor, vehicle speed, it\'s on tail shaft.

my guess, is the tail sensor is bad and you replaced the front sensor

P-0715 is a bad input sensor

P0720 and up are output sensor errors.

the 500 , is the 3rd sensor, the tail shaft sensor that runs the speedo

1st google hit.

next time post real DTCs

so we can jump on the exact part and the simple tests

the beauty of 3 sensors, is the transmission runs better

shifts better

and the OBD2 diagnostics are dead nuts, accurate.

it can see illegal gear slips (bad clutch packs) in any gear

and tell you. one of the best there.are

if you had new car, with 9speed, good luck keeping that card house going.. really.

Sep 26, 2014 | 1999 Jeep Cherokee

3 Answers

Automatic transmission input shaft speed sensor

(440) Automatic Transmission Input Shaft Speed (A/T ISS) Sensor Assembly


Jul 02, 2014 | 2004 Chevrolet Impala

2 Answers

Speed sensor

Speedometer sensor measures axle(driveshaft) speed for your speedometer gauge.
Input speed sensor measures the speed of the input shaft of the transmission.
The output speed sensor measures the output shaft, the ECM compares these two signals to determine the amount of clutch slippage and adjusts parameters accordingly for optimal operation.

Feb 02, 2014 | 2002 Kia Sedona

1 Answer

Have a 1995 ford explorer.had transmission rebuilt about 6months ago and have had problems said it was speedometer sensor so I had it changed.ran good for about 8hours then speedometer...

take it back the transmission shop it is under warranty for at lease a year. they did not do a good job. the shop to replace the speed sensor when they was rebuilding the transmission

Nov 03, 2012 | 1995 Ford Explorer

1 Answer

What would make the speedometer not work

Troubleshooting Speedometer Problems
Speedometer Cable Replacement
Take out the engine cover and doghouse to remove the speedometer cable from your car. Take out the bolt from under the dashboard, so that you can easily access the old speedometer cable. Also remove the nut on the rotating shaft and pull the speedometer cable out through the passage. Remove the clamps present on the transmission and engine compartment.

Once you have removed the old speedometer cable from your car, you need to replace it with a new one. In the adapter, fix the square end of the new cable and also tighten the nut on the rotating shaft. Pass the new cable through the passage and tighten the bolt at its rear end. This end should be fixed at the speedometer's square hold. Fix back the clamps you earlier removed and also put back the engine cover.

Speed Sensor Replacement for Front Wheel Drive Vehicles
You will find the speed sensor behind the engine above the trans-axle. Take out the connecting hose, air cleaner and electrical connector from above the sensor. With help of a 10 mm socket, take out bolts keeping the sensor in place. Simply twist the sensor to take it out. Fix the new sensor in place and tighten bolts around it. Attach back the hose, air cleaner and the electrical connector on to the sensor.

Speed Sensor Replacement for Rear Wheel Drive Vehicles
You will find the speed sensor on the driver's side behind the transmission. Raise the vehicle up from the driver's side and put a jack stand below to hold it there. Disconnect electrical connectors present on the sensor and take out bolts keeping the sensor in place, using a socket. Take out the sensor carefully and fix a new one in its place. Attach the electrical connector to it and tighten it.

Not every speedometer not working problem needs a replacement job. It depends on the cause. In case the dial is the problem, you can easily replace it alone. Problems with the little computer reading sensor signals call for the computer to be replaced. It is therefore important for you to take your car to a car mechanic and diagnose the predicament, before jumping onto any conclusions and trying to solve it yourself.

Hope this helps; also keep in mind that your feedback is important and I`ll appreciate your time and consideration if you leave some testimonial comment about this answer.

Thank you for using FixYa, have a nice day.

Feb 07, 2012 | 1995 Ford Explorer

2 Answers


hi , their is two different speed sensors on your vehicle one is the input speed sensor which is inside the transmission and the transmission will have to be removed to replace it the other one s the output speed sensor is located directly above the passenger side trans-axle shaft. your input sensor is the sensor which tells the transmission when to shift and the output speed sensor tells the speedometer what it should display and both those parts are fairly cheap they are around 15-25 dollars but just remember if your input speed sensor is bad it is gonna cost you a minimum of 1000 dollars to have a mechanic fix as the transmission needs to be removed hope this is what you needed

Jun 06, 2010 | 1995 Oldsmobile Aurora

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It sounds like it's your speed sensor in your transmission. It's an easy fix. Good luck

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