Frustrating Foxbody Speedo

[Keith5.0GT]

hey everyone. I’ll make it short. My speedometer and odometer just quit working. The cable and gear were fine but I replaced them anyway. I looked into trans opening and saw the gear on the input shaft, seemed good and didn’t spin by my finger. The cable can move speedo needle by hand so the head unit should be fine. So that should be it, all seems fine but no speedo! Also this is my second speedo cable that has leaked trans fluid from the crimp. I’ve search forums and found that a lot leak. Are any speedo cables not junk? Frustrated to the point I almost listed it for sale. Any help is appreciated. Thankyou.

 

[Mustang5L5]

Did you peer inside the hole in the trans and see if the drive gear was stripped or in place?

The drive gear on the t5 is held in place with a small clip and it's not uncommon for the clip to break and the drive gear to walk up the shaft and not contact the driven gear

 

[Keith5.0GT]

Did you peer inside the hole in the trans and see if the drive gear was stripped or in place?

The drive gear on the t5 is held in place with a small clip and it's not uncommon for the clip to break and the drive gear to walk up the shaft and not contact the driven gear

Yeah I did see a gear in there. I couldn’t say if it was in exact spot it should be though.... I wonder if I stuck speedo gear in there by itself if I could see if they made contact. Sounds like an idea

 

[2000xp8]

Pull the clip and cable from the trans and put a cordless drill on it while someone watches the speedometer.
If it works, you know the problem is in the trans, I think you can pull the tailshaft housing without pulling the trans, but I've never personally tried it.

If you do have to open the trans, use one of the speedometer gear kits at LMR or similar for the gear set you have.

 

[Mustang5L5]

If it works, you know the problem is in the trans, I think you can pull the tailshaft housing without pulling the trans, but I've never personally tried it.

It's a PITA to do unless you have two people. You'll need one under the car pulling the tailhousing, and one in the car trying to manipulate the shifter block and lining up the roll pin. I wouldn't do it personally.

 

[2000xp8]

It's a PITA to do unless you have two people. You'll need one under the car pulling the tailhousing, and one in the car trying to manipulate the shifter block and lining up the roll pin. I wouldn't do it personally.

You are probably right, it's only crossmember and trans bolts away from pulling the whole thing and a t5 isn't that heavy...

 

[Keith5.0GT]

You are probably right, it's only crossmember and trans bolts away from pulling the whole thing and a t5 isn't that heavy...

Yeah I had the trans out less than a year ago for clutch and everything. Sure wish speedo quit before that! Sucks. I did spin it by hand and the needle moved but I’ll try the drill too. I’m really slow so it takes me weeks to remove trans and do whatever work I need, so I want to be sure it’s that before I pull it haha. Tempted to sell it since it’s 90%working on it and only 10% driving it. But thanks for the feedback. I’ll regroup and take another look at it.

 

[Keith5.0GT]

You are probably right, it's only crossmember and trans bolts away from pulling the whole thing and a t5 isn't that heavy...

And nice mustang you have there

 

[Keith5.0GT]

Yeah I had the trans out less than a year ago for clutch and everything. Sure wish speedo quit before that! Sucks. I did spin it by hand and the needle moved but I’ll try the drill too. I’m really slow so it takes me weeks to remove trans and do whatever work I need, so I want to be sure it’s that before I pull it haha. Tempted to sell it since it’s 90%working on it and only 10% driving it. But thanks for the feedback. I’ll regroup and take another look at it.

Also when I spun the cable, I noticed it would only move the needle when I spun it in one direction but not the other. I’m gonna assume that’s because it doesn’t measure mph in reverse.

 

[General karthief]

Take a look at the plastic gear where the cable fits, make sure it still fits and not rounded out.

 

[Mustang5L5]

Also when I spun the cable, I noticed it would only move the needle when I spun it in one direction but not the other. I’m gonna assume that’s because it doesn’t measure mph in reverse.

The needle stop in the cluster prevents the needle from moving backwards. Set the trip reset to 0 and spin it and you should see the mileage start to go backwards.

If you are getting feedback from the speedo by spinning the cable down at the trans, the issue is most likely the driven/drive gear interface.

Is the drive gear centered in the speedo hole?

This isn't a t5 setup, but the drive/driven gear layout is the same. Drive gear is centered to the driven gear when you insert it

 

[Keith5.0GT]

The needle stop in the cluster prevents the needle from moving backwards. Set the trip reset to 0 and spin it and you should see the mileage start to go backwards.

If you are getting feedback from the speedo by spinning the cable down at the trans, the issue is most likely the driven/drive gear interface.

Is the drive gear centered in the speedo hole?

This isn't a t5 setup, but the drive/driven gear layout is the same. Drive gear is centered to the driven gear when you insert it

Great question, the gear inside of the trans is not centered in the hole. I had to reach my finger around to one side to feel it. I could see it though. So if you are saying that gear should be centered I’d say that was the problem

 

[Keith5.0GT]

Great question, the gear inside of the trans is not centered in the hole. I had to reach my finger around to one side to feel it. I could see it though. So if you are saying that gear should be centered I’d say that was the problem

Gotta get a second look sometime but all signs are pointing there unfortunately

 

[Mustang5L5]

Cheap fix at least. Just lots of labor

https://lmr.com/item/LRS-17336A/83-...MIjYemmtPa2AIVgkoNCh2NmQEfEAQYAiABEgIno_D_BwE


While you are in there, if you have the green 8 tooth drive gear I'd explore swapping it for a 6 or 7 tooth drive gear. It allows you to use lower tooth count driven gears which don't strip as easily.

 

[2000xp8]

Cheap fix at least. Just lots of labor

https://lmr.com/item/LRS-17336A/83-...MIjYemmtPa2AIVgkoNCh2NmQEfEAQYAiABEgIno_D_BwE


While you are in there, if you have the green 8 tooth drive gear I'd explore swapping it for a 6 or 7 tooth drive gear. It allows you to use lower tooth count driven gears which don't strip as easily.

I assumed all the gear kits from lmr gave you the right drive gears. I could be mistaken, but I thought that was the point of the kit. Especially since different gear sets have different color drive gears.

https://lmr.com/item/LRS-17285C-K/83-95-Mustang-Speedo-Gear-Kit-T5-With-373-Gears

 

[Mustang5L5]

I assumed all the gear kits from lmr gave you the right drive gears. I could be mistaken, but I thought that was the point of the kit. Especially since different gear sets have different color drive gears.

https://lmr.com/item/LRS-17285C-K/83-95-Mustang-Speedo-Gear-Kit-T5-With-373-Gears

I didn't know LRS was selling these as kits, but the above makes sense.

Of course the OP never stated what he had for gear colors, so he could have these parts already. He could also have a different rear tire size as well meaning he'd have to buy the drive and driven gear separate to get the speedo right. LRS has a calculstor for that.

Looks like LRS sells their kits with the 7 tooth or black 6 tooth gear anyway. I'd recommend anyone with an 8 tooth gear to ditch it if they have to open their trans for any reason if they plan to run 3.73s or higher gears.

 

[Keith5.0GT]

I didn't know LRS was selling these as kits, but the above makes sense.

Of course the OP never stated what he had for gear colors, so he could have these parts already. He could also have a different rear tire size as well meaning he'd have to buy the drive and driven gear separate to get the speedo right. LRS has a calculstor for that.

Looks like LRS sells their kits with the 7 tooth or black 6 tooth gear anyway. I'd recommend anyone with an 8 tooth gear to ditch it if they have to open their trans for any reason if they plan to run 3.73s or higher gears.

The drive gear looked white from what I could see. The speedo was 10mph off when I bought the car, and after a new driven gear it was 4mph off. I think I selected the wrong gear because I guess the wrong drive gear tooth number. Don’t know if that would cause a problem with engagement or just calibration. I have a new driven gear that should be correct, just sounds like the drive gear isn’t in place and I need a new one, so far. I wanted to upgrade gears from 3.08 but I’ve spent so much unexpected money I’m just gonna leave it alone. It’s just a cruiser anyway, stock heads and cam.

 

[Keith5.0GT]

But I am gonna spin the rear tires and watch the drive gear and really check it before I go through the repair. Cuz that’s agony for a beginner like me.

 

[Mustang5L5]

What gears do you have?

White is the 23-tooth, which is prone to stripping. Tell us your gear ratio and tire size and we can recommend a speedo gear setup to use should you decide you have to get into the trans to replace the clip. If you can get the t-5 out, it's not that bad to do. However I'd be 100% sure before doing that.

Once you get the tailhousing off, it's right there

 

[Keith5.0GT]

What gears do you have?

White is the 23-tooth, which is prone to stripping. Tell us your gear ratio and tire size and we can recommend a speedo gear setup to use should you decide you have to get into the trans to replace the clip. If you can get the t-5 out, it's not that bad to do. However I'd be 100% sure before doing that.

Once you get the tailhousing off, it's right there

Well the driven gear I bought is white and it’s 17 teeth. I used the calculator on lmr. 3.08 gears in rear end with 245-45-17 tires. The transmission I’m told is a world class t-5 so I think the drive gear is supposed to be 7 teeth.