speedo question

[dman1982]

Originally Posted by USArmyCombatMedic

Personally, I would check to make sure that the speedo cable is all the way on. If so, I would disconnect and lube the end of the cable. It is suppose to be pretty well lubed which thinking back to when I did mine, I forgot to lube the new cable which could explain my problem. Also, when you say jump all over the place, I assuming you mean it bounces as in your going 25MPH the needle will bounce from 15ish to 35ish? Or like random jumps from 5MPH to 85MPH to 30MPH?

it bounces and if I'm going say 25 mph it will say I'm going 75, it also bounces...really annoying

[dman1982]

Originally Posted by f.monroe

Lubricate the cable as mentioned above. It was probably a little dry and just moving it will cause a bouncing speedo sometimes. The cable binds and lets go causing the fluctuation you see. The inner cable comes out real easy. Do not over lube it.
Frank

what should i use to lube it? wd40?

[bigd65]

Take it off and pull the cable out of the housing. Then get some of that white spray grease and shirt some down the housing and while inserting the cable back in, or replace if you see any bad sections on the cable. Spray some on the cable as you re-insert then make sure it's connected right. The cable is either dry or kinked. If kinked, you can get a replacement insert from your local parts house...

[USArmyCombatMedic]

I still think it sounds like a sticky cable. Personally I would use white lithium grease, second option would be LIQUID graphite. Not solid. If using the white lithium grease take a decent portion in between thumb and pointer finger and run the entire cable through. This way you lube the entire thing without getting too much lube which could be problematic down the road. I would also make sure to get a little extra lube on each if the ends. Careful not to make a mess and cover the speedo though!

[C10wip]

I did this last week; use white lithium grease and it fixed it; at 40 the speedo would bounce up to 70 or so and make a pile of noise. I tried silicone spray first but that only sort of worked. I also read somewhere that you should not lube within 12" of the instrument cluster end or the lube will end up getting flung around.

[dman1982]

so i think i may have figured out the problem, when i changed out the speedo gear i pulled it from a blazer that was a 89 or 90 maybe even 91, i changed the gear and it sordof worked, after comparing my cable with the one i pulled from the blazer the one from the blazer is about 10 inches longer or so, i believe the cable isn't catching the gear all the way, is this a good guess? or am i just a dumb a$$???

[bnoon]

Originally Posted by dman1982

so i think i may have figured out the problem, when i changed out the speedo gear i pulled it from a blazer that was a 89 or 90 maybe even 91, i changed the gear and it sordof worked, after comparing my cable with the one i pulled from the blazer the one from the blazer is about 10 inches longer or so, i believe the cable isn't catching the gear all the way, is this a good guess? or am i just a dumb a$$???

If you changed the speedo gear, that can also be the cause. If the cable is good-n-lubed, and the ends are not rounded off on either end of the cable, then your speedometer gear could also be partially stripped (not only the gear side, but where the cable inserts could also be partially stripped).

Using the Blazer or truck speedo cable will not cause any issues as long as the ends are the same and it reaches without binding.

[dman1982]

Originally Posted by bnoon

If you changed the speedo gear, that can also be the cause. If the cable is good-n-lubed, and the ends are not rounded off on either end of the cable, then your speedometer gear could also be partially stripped (not only the gear side, but where the cable inserts could also be partially stripped).

Using the Blazer or truck speedo cable will not cause any issues as long as the ends are the same and it reaches without binding.

ya i used just the gear, but I'm going to pull it tomorrow to make sure that its not rounded off in there, the cables look fine tho

[Irish1941]

Easy test:
put a drill on the cable underneath at the t-case and spin it up.
Have a buddy watch the speedo inside.
No bounce: gear swap is the problem
Still bouncing: cable is problem.
The gear could have only come from a '89 or down Blazer. All electronic in 90-91.
As was said, as long as there is the square cable end coming out of the sheath then it should work.
Also, remember most of the late Blazers (87-89) came with a 2.73 or 3.07 gears so the t-case gear you put in is more than likely wrong and giving you wrong speedo readings. Not sure what gears you have but pretty sure it's reading wrong.

[dman1982]

Originally Posted by Irish1941

Easy test:
put a drill on the cable underneath at the t-case and spin it up.
Have a buddy watch the speedo inside.
No bounce: gear swap is the problem
Still bouncing: cable is problem.
The gear could have only come from a '89 or down Blazer. All electronic in 90-91.
As was said, as long as there is the square cable end coming out of the sheath then it should work.
Also, remember most of the late Blazers (87-89) came with a 2.73 or 3.07 gears so the t-case gear you put in is more than likely wrong and giving you wrong speedo readings. Not sure what gears you have but pretty sure it's reading wrong.

thanks, ill try that tomorrow, my truck has 3.08's and 35 inch tires, so it will be off regardless, but still more accurate than what it is now....pretty anxious to try this out...thanks again

[dman1982]

well i figured it out, its the speedo....the round wheel that connects to the speedo has about a 1/4 inch of play in it, i have another speedo but the mileage is way off of mine, how do i change it to match my speedo?

[dman1982]

i know i can hook a drill up to it but thats going to take forever, is there a faster way?

[dman1982]

well gents, just went on a test run, working like a charm, well still five mph off, but at least i know how fast I'm going....thanks for all the help....still boggles my mind how it worked one day then not the next, i didn't drop it or anything but heck its working now