My last bug to wig out... speedometer question

[mobileaudio25]

I see you already did the math, so to speak. From my chart, it appears that you need 8-tooth drive gear and a 23-tooth driven gear. ..whichever comes closest to the 2.93 number.
The chart indicates a 23 tooth gear for a 2.88 ratio. and a 24-tooth gear for a 3.00 ratio.
Unfortunately. there's no in between. I'd start with the 23-tooth gear...and of course the 8-tooth drive gear. If someone has the gears cheap enough, buy the 24 tooth as well. They're relatively easy to change out.
RockAuto might be a good choice to buy speedo gears. That's the last place I bought a new driven gear.

I'm running a 25.7in tall tire. My local jegs has all of the speedometer gears in stock. I did do the math and thank you for verifying that I did it correctly. Using the chart and confirming with a tci rep also they recommended an 8 tooth and a 23 tooth speedo set just like you did. I know for a fact in my tailhousing I have a purple gear which is a 10 tooth and won't get me close at all to where I need to be. About $42 for all the gears and a new clip. Regardless I'm going to need new gears because they won't work with my application.

While I am redoing my speedo gears and have to pull the tailshaft housing off I'm going to replace what I can. What all do I need a tailshaft housing gasket and a new seal is that all?

My cable is brand new also so we should be good there.

 

[Longroof79]

I'm running a 25.7in tall tire. My local jegs has all of the speedometer gears in stock. I did do the math and thank you for verifying that I did it correctly. Using the chart and confirming with a tci rep also they recommended an 8 tooth and a 23 tooth speedo set just like you did. I know for a fact in my tailhousing I have a purple gear which is a 10 tooth and won't get me close at all to where I need to be. About $42 for all the gears and a new clip. Regardless I'm going to need new gears because they won't work with my application.

While I am redoing my speedo gears and have to pull the tailshaft housing off I'm going to replace what I can. What all do I need a tailshaft housing gasket and a new seal is that all?

My cable is brand new also so we should be good there.

I'm glad I could be of help. As you see, I've done this a number of times before. Mostly due to changing tire diameters.
It probably wouldn't be a bad idea picking up a rear seal..that's about all you'll need besides the gears and clip. There's no gasket between the tailshaft housing and trans case.
The replacement gears will make a world of difference in how your speedo registers.

Using a good grade grease...say that fast three times...Lol!! on the inner cable is highly recommended.

 

[mobileaudio25]

I'm glad I could be of help. As you see, I've done this a number of times before. Mostly due to changing tire diameters.
It probably wouldn't be a bad idea picking up a rear seal..that's about all you'll need besides the gears and clip. There's no gasket between the tailshaft housing and trans case.
The replacement gears will make a world of difference in how your speedo registers.

Using a good grade grease...say that fast three times...Lol!! on the inner cable is highly recommended.

I hope I never have to mess with this again haha. I'm getting custom brackets welded to my new seats and I'm going to take it to a buddy's house with a lift. Prolly be a week I will let you know what we find.

I read to use dry graphite lube. I looked on Amazon
https://www.amazon.com/gp/product/B0016GZQ60/?tag=gbody-20

Is this good or is there something better you recommend?

 

[Longroof79]

The reason why I suggested jacking up the rear of the car, is because you won't have to drain the trans fluid when you remove the driveshaft and tailshaft housing.
As for grease, I suppose you can use the dry graphite lube, but I used regular grease that you'd grease your ball joints and tie rod ends with.
When you purchase a new speedo cable, they sometimes provide a small tube of grease...not always the case, though.

 

[Texas82GP]

Use some silicone sealer when you put the tail housing back on.

 

[mobileaudio25]

So today I took the tailshaft off, replaced it with a new drive gear, driven gear, clip, speedo gear housing, seal and bushing.

I put everything back together and took it for a test drive, speedo still does not work correctly. When I put it in drive and gas it the speedo will go from 0 to 85 instantly.

Gears are new and cable are brand new, cable was lubed with dry graphite lube.

Does it matter which way the drive gear is installed? Is there a certain way it needs to be facing could I have maybe installed it backwards?

If I move the cable at the dash with my hands it won't turn so I know the cable is installed correctly. My needle does move freely and if I spin the cable hookup it will move the needle. Could it still be the issue?

What do you guys think?

 

[pontiacgp]

I would try a different speedo head

if you are trying it figure out why this repair is a pain in the butt it is your fault, you jinxed it by saying it's the last bug you have to fix...

 

[mobileaudio25]

I would try a different speedo head

if you are trying it figure out why this repair is a pain in the butt it is your fault, you jinxed it by saying it's the last bug you have to fix...

Hahah I know I thought I was there !

Do you know if there is a certain way the drive gear is installed or does it not matter?

I'm going to make a trip to mikes montes next tuesday. He has a cluster there I'm going to try the speedo out of it. I really hope that is the problem I'm stumped on whatever else it could be ! I want to get this dash put back together !!
I've been putting about 25-30 hours a week in. Starting to come together!

 

[pontiacgp]

here is a picture of one...

 

[mobileaudio25]

here is a picture of one...

Yeah that's how mine is installed. After looking at my old drive gear it doesn't matter which way the gear is facing because the grooves run the same direction regardless. I'll be trying a new speedo head Tuesday. I'll let you know the outcome...