How Fast Am I Going? - Montana Owners Club

jsrang · 09-13-2006, 12:29 PM

My speedometer needle is sticking at different MPH numbers which can be a bit scary at times. It might stick at 55 mph until I stop, or it might stick temporarily at 55 mph, then when I drop in actual speed to maybe 35, and again speed up, the needle actually starts moving up from the 55 mark so that at an actual speed of 55, the speedometer says 75! (Are you still with me?) The needle doesn't reset until I shut off the motor and restart. Sometimes I have to hit the starter several time as the needle ratchets down a little each time. Darnedest thing I've ever seen. It just started doing this 3-4 days ago and plan to stop at a dealer, as soon as I can find one. My TV is a Chevy 04.5 D/A (Late model 04 with the LLY engine). Anyone out their ever had a similar experience? I doubt this is covered under warranty, since I have about 57k miles on it, unless I can convince the Dealer the speedometer is part of the drive train? (Waiting anxiously to hear your comments/thoughts as this certainly has me baffled.)

Jim

Jim & Marilyn Rang
2004 2500 CC Silverado SRW Duramax/Allison
2005 3650 Montana RK

steves · 09-13-2006, 12:36 PM

Get a GPS and it will tell you your speed.....my Garmin 2720 gives the MPH and I assume other GPS brands do too.

Steve & Betty (AKA steves)
2005 3400RL Montana
2006 F350 PSD SRW CC LB 4X4 King Ranch

bsmeaton · 09-13-2006, 12:44 PM

I'd like to tell you the speedo cable needs lubed - but I'm just going to bet they don't use cables anymore - probably digital telemetry straight from the wheels or driveshaft or some other crazy technology!

Sorry I can't help - but it doesn't sound cheap!

Brad

BillyRay · 09-13-2006, 01:39 PM

no, and never heard of it before.

BillyRay

2002 3500 Chevy D/W 4x4 C/C Diesel
2004 3685FL

stiles watson · 09-13-2006, 02:40 PM

If it is controled by an electronic sensor, it sounds as if it is dirty or malfunctioning. If it is mechanically driven, it sounds as if he gear mechanism needs lube or the cog has slipped or has a broken tooth. If the cable has not fit well from the beginning, it may have taken this long to wallow out the connection point, so slipping and sticking.

Of course it may be nothing I have mensioned. Really hard to see over the net.

Stiles n Dianna
"Life is an adventure unfolding"
03 3670RL Big Sky
02 Ford F250 Lariat Longbox 7.3L PSD
Hypertech Programmer III
Prodigy

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trukdoc · 09-13-2006, 03:23 PM

My vote would be a bad speedo head. If it was a sensor malfunction it simply would drop to zero as the signal is lost. The needle sticking and having to ratched down useing the key tells me the problem is in the dash.

Rick & Wanda R.
2005 F250SD Lariat 4DR.
6.0 Powerstroke
2005 Mountaineer 328RLS
Sulphur Springs, Texas
Kids: Lexus and Sunshine

OntMont · 09-13-2006, 03:24 PM

I am pretty sure that although it looks analog, it is actually a digital device driven somehow by the engine or transmission computer. I would get it checked, because there may be other less visible things going on.

Microsoft Streets and Trips will give you a GPS speed reading, if it just a read-out problem.

OntMont (John and Donna)
2005 Montana 3670RL
2007 Silverado "Classic" 3500 DRW 4x4 CC D/A.
2001 Border Collie to ride herd on us.

trukdoc · 09-13-2006, 03:31 PM

The speedo reads magnetic pulses turned to AC or DC current depending on model. The pulses are sent to the CPU and then to the speedometer and antilock brakes. There is no cable anymore. And since the signal is in pulses that would be digital.

Rick & Wanda R.
2005 F250SD Lariat 4DR.
6.0 Powerstroke
2005 Mountaineer 328RLS
Sulphur Springs, Texas
Kids: Lexus and Sunshine

LonnieB · 09-13-2006, 03:42 PM

I agree with Rick, it's completely electronic, and more than likely in the speedo head.

Lonnie
2006 Montana 3000RK, Reciever Hitch for Boat and Toy Trailer
2003 F250 CC PSD, LB, 6 Speed Manual Trans., 4X4, Air Suspension, Husky 15K Hitch

Wrenchtraveller · 09-13-2006, 03:45 PM

My 2000 F350 had a motion sensor fail and cause the speedometer to do a bunch of weird stuff.
This sensor is plugged into the rear end of the vehicle and is a fairly common thing to fail on a Ford. The truck was under warranty so I let the dealer fix it but I believe it is not a very pricey fix.

Your Chev probably has something similar.

Don & Donna
Vancouver Island
2005 Ford F350 V10 Lariat CC 4x4 LB SRW 11200 GVWR
2006 Montana 2955RL

click on the little pic to see a big pic

jsrang · 09-13-2006, 03:46 PM

Thanks for your thoughts and input. Since, I can hear a clicking sound when the speedometer ratchets down, it would seem to be mechanical, but then again maybe not. Also, it is a sporadic malfunction as it sticks only occasionally. Not every trip. I also forgot to mention that thanks to the Tach, I know roughly what my speed is, ie @ 2000 RPM I'm doing about 65 MPH and can guess the rest. If I have my MS Streets & Trips on, then I have accurate speed as well. It definitely sounds like a trip to the Dealer Doctor.

Jim

Jim & Marilyn Rang
2004 2500 CC Silverado SRW Duramax/Allison
2005 3650 Montana RK

jsrang · 09-14-2006, 02:57 AM

Since the problem is sporadic, will the Dealer Service Dept be able to find the problem if the Speedometer happens to be reading OK when I take it in? In other words will their be an electronic signature of the problem, regardless if the malfunction is not visible on the speedometer at that specific inspection time? (Does my question make any sense?). Thanks!

Jim

Jim & Marilyn Rang
2004 2500 CC Silverado SRW Duramax/Allison
2005 3650 Montana RK

pud2 · 09-14-2006, 03:13 AM

I am with wrenchtravler Had the same happen oh my 95. It would also make the truck run bad and the tranny shift weird because of the computer.

Darrell&Pam
06 3670
06 F350 Lariet P.S.D. C.C. DRW.
Husky 16k glider
Huntly-Yorkie
Zachary,La.

skypilot · 09-15-2006, 12:04 PM

Jim: Your speedo is electronic, controlled by a circuit initiating at the transmission through the ECM which then provides a variable voltage to the speedo head. Stepper motor in the speedo head is probably what is sticking (and what you hear clicking). Not sure on warranty anymore but used to be covered 36/36; if it impacts on drive train (specifically some of the EPA smog stuff) then could be covered much longer. I say take it to dealer for eval if nothing else.

jsrang · 09-15-2006, 05:20 PM

SkyPilot, Thanks for your input. I plan to get it to the Dealer ASAP. I'll say it again, this is an awesome forum.

Jim

jsrang · 10-07-2006, 04:58 PM

UPDATE! I took my Chevy to the Dealer Doc last week and had the speedometer inspected. The cluster assembly is the culprit and will eventually have to be replaced. However, I was informed that there is no affect through either engine or tranny computer. Since the problem is very sporadic and hasn't happened in the last few weeks, I will probably delay getting it fixed until it gets much worse or fails. The part will have to be ordered as it is not a stock item. Parts and labor will be about $450. Turns out it is not covered under the 100K engine warranty. So, since it appears to be only a nuisance issue, I think I will procrastinate for awhile on this one. Thanks all for your input and insights.

Jim

bsmeaton · 10-23-2006, 07:46 AM

Jim,

Just had to reopen this post! We were just discussion MOCondriacs where you have a fear that what happens to others will happen to you.

My daughter started laughing Saturday from the back seat in my new Ford and pointed at the gauges - while traveling down the highway my Speedometer was reading 20mpg and the tachometer needle had actually rotated around and pushed the turbo boost gauge needle off the scale. Looks like it's off to Ford tomorrow!

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