Fuel, Speedo and Odometer not working

[bbqfan5909]

I need some help here...new to the Military Blazer. My Fuel, Speedo and Odometer is not working at all. Where should I start???

 

[319]

Start at the TMs, available from the resource section. Fuel gauge or sending unit could be bad. "Speedo" is probably the cable.

 

[HAWKMAN]

Check ground for the sending unit.

 

[bbqfan5909]

Does anyone have pictures of where the sending unit is at and where the ground is???

 

[TyJustice]

You can find the gound wire connected to the frame by the rear driver side tire..

In reference to the speedo..Does anyone know how many teeth are on the drive gear that is inside the transfer case? Options from GM is 28 or 31/32 not sure..

Thanks

 

[bbqfan5909]

When you say near the rear tire to the frame...where at??? There are some wires running there, need exact location.

Thanks,

Casey

 

[bbqfan5909]

With the speedo, the cable runs all the way to the transfer case and not cut. I am having a hard time unbolting the assemble on the transfer case to check for teeth but can unscrew the garmet before it. The cable does not spin at all by hand for that point, I am guessing that is not good.

 

[HAWKMAN]

Correct, if the cable will not turn with your fingers then it is seized and needs replacing. The top of the fuel tank is notorious for collecting road dirt, take your garden hose and try to clean off the top of the tank so you can see the sending unit better. The ground wire has a small screw that bolts it to the frame, that is where it would help if you could clean the contact to the frame.

 

[bbqfan5909]

Where can I get a new one from and is there any directions for replacing the cable for the speedo?

 

[kennyw]

Any auto parts store sells them, just ask for parts for an '85 Chevy K30 w/ 6.2L and TH400 auto. I'm sure any Chilton will cover replacing a speedo cable.

 

[HAWKMAN]

Your best bet is to go new, no big deal to change.

 

[bbqfan5909]

Is there a write up on replacing the cable on this site? I am guessing I will having to take the dash apart to get to the back of the speedo itself?

 

[kennyw]

Remove old cable, install new cable... it is that simple. Nothing to take apart as you can reach the back of the speedo from under the dash. All you have to do is hold down the clip with one finger while pulling the cable off with the rest. New one pushes on. You can't take the dash apart without taking the cable off first

If you need more instructions than than there are repair manuals available in the TM section of this site or you can buy a Chilton at any auto store. Also, you may benefit from an auto repair class at the local community college.

 

[bbqfan5909]

I took the old cable out and oiled it up...it was in decent shape other than what looked to be a burn mark. It now spins freely but speedo still does not work!

 

[Armada]

It now spins freely but speedo still does not work!

Did you have the cable engaged all the way onto the speedo? The square drive cable end needs to be aligned with the gauge's square socket before it can be inserted completely.
Hook the drive end of the cable back up with the speedo end laying loose and take the truck for a drive or raise and support the rear tires. Have 'soldier B' look at the end of the cable while you drive and see if it is turning. If it is, the problem is in the gauge.

 

[bbqfan5909]

Well, when the cable spins the speedo is working. So I am assuming the speedo is not the problem...so I pulled the plastic gear from the transfer case and attached it see if it worked with that and it did not. Does the plastic gear in the transfer case come out of the hosing or is it attached some how? Where can I find one for a good price...I would like to get it local so I dont have to wait for shipping.

 

[kennyw]

It sounds like you already pulled one gear, the other gear is wrapped around the output shaft and requires removal of the output housing to get it off.

 

[motormayhem]

The gear on the shaft in the T-case it inside the slip yoke housing that bolts on the back of the main case. Remove the rear drive shaft (when you take it out of the T-case side it will leak fluid), take the bolts out that hold that housing on (I think there are 4) and the gear simply slides on and off the main shaft. When you go to put it back together make sure the shaft has not moved out of the transmission as there is a bearing on the front of the planetary setup (very thin washer like bearing) that can fall off of it's little place and prevent the shaft from sliding all the way forward. The housing should go all the way on by hand. DO NOT use the bolts to pull the housing forward.

 

[bbqfan5909]

I dont believe I have to pull the transfer case, its only the plastic gear that is stripped out and its not the teeth but the inside of the tube where the speedo cable attaches.

 

[Wolf.Dose]

I do not think that the metal part in the T-case is falty. To my understanding the cable itself to some reason is too short inside to make a real safe drive of the speedo. This happens some reare times. The siutable repair is to replace the speedo drive cable.To my experiance the shops say that this will never happen, but it will.
Else you have the problem to disasemble the T-case as desripted in previous answeres.
Try hard; with the replys you will find a solution.
Wolf from Germany
16 years with a CD10516 Mil Blazer.