trouble shooting no speedometer

[jmmay82]

Hey I have had no speedo since I got m1009 the needle and the shaft on the gauge was broken so I assummed I just needed to replace the gauge so I did and now it still doesn't work what is to be checked and where can I get these type of parts and trouble shooting tips would be appreciated

 

[Mudstone]

lmc truck sells the sensor and its not cheap... i currently go with the "oh they are going a little faster than me... i'm probably good" method

 

[4x4 Forever]

You can go online to www.gmpartsdirect.com or www.oempartstoday.com or www.rockauto.com or www.ebay.com and look through their catalogs and you should be able to come up with a speedo and a cable, if needed. Ive looked through gmpartsdirect and epay just to see what i could find and I found the speedo and cable, this was a couple of months ago. Match up what you have to what is on the screen and you should do ok, 80's series truck with 85mph markings.

The speedo is easy to change and the cable is kind of a booger to do but is definately an afternoon project.

Good Luck!

 

[Somemedic]

Theres a module inside the side of the transmission. Has a plastic gear that strips out and is usually a general PIA, pricey, but fairly easy to change. Its where the speedo cable connects. Pull one out of a used truck at a yard, and Id have to guess it would have to be out of any TH400. Might have to get a ruling on that from Mangus or some other guru.

 

[4bogginchevys]

I got a question too!

Theres a module inside the side of the transmission. Has a plastic gear that strips out and is usually a general PIA, pricey, but fairly easy to change. Its where the speedo cable connects. Pull one out of a used truck at a yard, and Id have to guess it would have to be out of any TH400. Might have to get a ruling on that from Mangus or some other guru.

As you stated in your thread, the speedo hooks to the tranny....mine hooks to transfer case and odometer works, but no speedo. What gives....should I try connecting to tranny? Will my speedo be accurate if it works....Thanks to anyone with info, I like to do about 2-3 over(up to 53 w/1008..) lol

 

[POOR WHITE BOY]

All gmc/chevy 4x4 m1008 and m1009 models the speedometer cable hooks to the transfer case not the tranny.

 

[jmmay82]

is ther any tricks to replace the nylon gear in the transfer case

 

[BlueToes]

I got a related question as well! my m1008 speedo cable is chirping up a storm. Been told it just needs some lube'n. Is it best to pull it from the bottom at transfer case?

 

[Stihl029]

IIRC you can only pull it out in one direction. yes try lubing it up.

 

[zyrtecx]

My speedo was not working and I tried another speedo and still no speedo, pulled the speedo cable out and lubed and still nothing... But I could turn the speedo cable from underneath the vehicle and the speedo worked... So, I checked the main gear on the output shaft by removing the device that holds the gear that mates with the output shaft gear and both gears appear to be okay. I then replaced the control box that speedo cable connects to and connects to the transfer case speedo drive gear. The speedo is working now! but it is very jumpy after I have driver several miles... When the vehicle is cold the speedo is not jumpy... And it appears to right on money with my GPS... I still need a new control box but have no idea where to get on! Note... The control box I used was from a parts M1009 that I have. Anyone have any idea where a new control box can be obtained?

 

[POOR WHITE BOY]

Try e bay or a salvage yard

 

[zyrtecx]

See attached image...

CONTROL BOX, Item#8:

Item#: 8
SMR Code: PAOZZ
CAGER: 11862
Part Number: 368026
DESCRIPTION AND USABLE ON CODES (UOC): ADAPTER,SPEEDOMETER, 1, UOC:209

 

[POOR WHITE BOY]

Speedometer will work without it . All it does is calibrate it for different axle ratios used in

 

[zyrtecx]

But how accurate will the speedo be without it? Does anyone know?

 

[POOR WHITE BOY]

Mine read alot slower when i removed it . But i am sure every truck is different

 

[4x4 Forever]

Those used to be a dime a dozen, back in the 80's. Might try junkyards and see if you can get one or a couple and try them against your GPS. I have no clue as to where to get a new one now. On second thought, you might swing by a tranny shop and see what they can come up with.

 

[dieselpony]

Try Speedometer Gear, Speedometer Gears, Ford, GM, Dodge 700R4 .

Scroll down to GM/Ford/Dodge Ratio Adapters. If you still have your old adapter laying around the ratio should be stamped on it.
A good transmission shop can build you an adapter with nearly any desired ratio though.

For calibrating your speedometer you can use this little online program: Speedometer Gear Computation

I had to do some math to calculate the teeth on driven gear and using the right adapter when swapping from a NP208 to 205 on my M1008. We'll see if I succeeded when the beast is on the road again.

Walter

 

[CUCV85]

[quote=Mudstone;492185]lmc truck sells the sensor and its not cheap... i currently go with the "oh they are going a little faster than me... i'm probably good" method[/quote]

 

[Mudstone]

mine just bounces around