Why is my speedometer doing this? Video included

[91CoupeMike]

http://www.youtube.com/watch?v=J29S40NaE9U&feature=youtube_gdata_player

I put in a new cable and gear during the summer.

[SonicblueGT03]

My '85 did that when I put the new cable in. Turns out I didn't get it pushed in the speedo tight enough. Pulled the gauges back out, pushed it on as far as it would go, no more jumping.

[91CoupeMike]

Will check. Thanks.

[Snatch Napkin]

It's either the cold affecting the cable, the cable got too hot next to a header, the gear is chewing up due to mismatched gear set, the cable is not seated properly, cable needs lubricating with graphite powder, or the cluster is wearing out. I think I covered them all.


When you replaced the speedo gear, did you check to see what gear was on the tail shaft?

[91CoupeMike]

Yellow gear in tail shaft, red gear on the cable.

I lubed the cable good when I put in, with the grease they sent with it.

I bet it's just loose on the back side. It started doing this when it got cold.

[donnie90stang]

Mine was doing the same thing... and now it does nothing, cable snapped or the gear is trashed...

[91CoupeMike]

Mine was doing the same thing... and now it does nothing, cable snapped or the gear is trashed...

That's encouraging.

Oh well, less then 30 bucks for all new parts if that's the case.

I just hate pulling the dash bezel. It doesn't make any noises now, and id like to keep it that way.

[FoxBodyNick]

its your headlight switch. =)

[Torinoman]

low blinker fluid?

[Dacotua]

Did you REPLACE the plastic gears in the transmission?

(The color on the end of the speedo cable doesn't matter, its the tooth count that matters. I've bought speedo gears before with the same tooth count and different colors).

The yellow main drive gear can get worm and cause your speedo to do what its doing.

(Changing out the yellow main drive gear is lots of fun... You have to take the transmission out, remove the shifter, remove all 10 or so bolts holding the tailshaft to the main body, knock the roll pin out of the shifter rail, pull the tail shaft off, pull the gear off, replace, reinstall in reverse order.).

[streetscraper1]

You sure you're not burning out in 3rd gear again?

[91CoupeMike]

Did you REPLACE the plastic gears in the transmission?

(The color on the end of the speedo cable doesn't matter, its the tooth count that matters. I've bought speedo gears before with the same tooth count and different colors).

The yellow main drive gear can get worm and cause your speedo to do what its doing.

(Changing out the yellow main drive gear is lots of fun... You have to take the transmission out, remove the shifter, remove all 10 or so bolts holding the tailshaft to the main body, knock the roll pin out of the shifter rail, pull the tail shaft off, pull the gear off, replace, reinstall in reverse order.).

The trans Is 6 months old. Rebuilt by thesource.

The teeth count on the cable was consistent with what I ordered and is red.

To my knowledge the yellow tailshaft gear doesn't have issues with stripping gears like the black tailshaft gear does. (late model t5).

Pulling the transmission is a breeze. I can have it out it roughly 35 min, and that work doesnt sound too hard, just time consuming. I'm sure it's cable related because it did this imeditaly after I installed it then it was fine until this week.

I'm sure it's something simple, just wasn't sure if clusters do this when they fail.

Also, I put the red gear on 21 tooth I believe and it was always reading 7mph fast. Car has 3.73s. And I checked by rotating the pinion flange and seeing how many turns it took to rotate the tire once.

[RuStYpNuS]

My cluster does that. Unfortunately my cluster is worn out.

Yours is either that or loose cable I bet. Easy fix for you.....I won't be fixing mine till I find a four eye 140mph gauge

[Dacotua]

The trans Is 6 months old. Rebuilt by thesource.

The teeth count on the cable was consistent with what I ordered and is red.

To my knowledge the yellow tailshaft gear doesn't have issues with stripping gears like the black tailshaft gear does. (late model t5).

Pulling the transmission is a breeze. I can have it out it roughly 35 min, and that work doesnt sound too hard, just time consuming. I'm sure it's cable related because it did this imeditaly after I installed it then it was fine until this week.

I'm sure it's something simple, just wasn't sure if clusters do this when they fail.

Also, I put the red gear on 21 tooth I believe and it was always reading 7mph fast. Car has 3.73s. And I checked by rotating the pinion flange and seeing how many turns it took to rotate the tire once.

21 tooth gear is for 3.55 gears.
You need a 23 tooth gear for 3.73's.

Yes the yellow transmission gear can get worn and do this. I'd be willing to bet yours is worn. Even when a tranny place rebuilds them, rarely do they replace that gear unless you say something.

[RuStYpNuS]

21 tooth gear is for 3.55 gears.
You need a 23 tooth gear for 3.73's.

Yes the yellow transmission gear can get worn and do this. I'd be willing to bet yours is worn. Even when a tranny place rebuilds them, rarely do they replace that gear unless you say something.

if theSource rebuilt his then im sure he checked the gear out