Speedometer cable continues to break....wtf?????

[Blown331LX]

Alright so Ive replaced the speedometer cable 3 times already and its broken again. Every time the cable breaks the gear in the trans gets chewed up also. The first time the cable broke it started with a bouncing needle and this was all because I didnt remove the cable from the sheath and lube it before installing. The past 2 times it got a new cable (removed and greased) and new speedo gears. The instrument cluster head has been removed and thouroughly inspected and works smoothly by hand.... Im at a loss but this is driving me crazy, anyone had this repeat issue before????????

 

[jrichker]

Are you replacing the just the inner flex cable or the flex cable and outer sheath?

If you have been replacing only the inner flex cable, it is time to replace the cable assembly, meaning the inner flex cable anf the outer sheath. Often the sheath will get damaged allowing moisture to seep into the intter workings and bind things up.

 

[Blown331LX]

Yes I have been buying the complete new cable sheath and all, Ive got the first 2 from Advance Auto Parts, figured they were junk so I switch and got one from Carquest and that one broke also. Ive hand spun everything before installation and driving and it seems to work fine for about 1,000 miles then craps out again. Could the soft plastic gear be causing this??? I know its not cable routing because it is attached to the factory mounts, and its a World Class T-5 behind a 306, so its not like some crazy combobilation of parts either. Ive never had this issue with any of my other Mustangs or my friends Mustangs, just puzzles me, I dont even know what else to check for.

 

[BlownFiveLiter]

It could still be the routing, even on factory mounting points. I had the one in my 90 break a couple times before I really examined it. Mine had a pretty sharp curve to it that I was able to correct and it lasted about 2 years before I got rid of the car. Running too close to a primary tube on the headers will do it, too.

 

[2000xp8]

If a ford part is available, get theirs.
carquest is no better than advanced auto.

 

[Blown331LX]

It could still be the routing, even on factory mounting points. I had the one in my 90 break a couple times before I really examined it. Mine had a pretty sharp curve to it that I was able to correct and it lasted about 2 years before I got rid of the car. Running too close to a primary tube on the headers will do it, too.

Thanks, good suggestion, I will recheck it later tonight. Do you know if theyre available in different lengths by any chance??? I think I will take the additional advice and buy a Ford cable if I can"t find anything wrong with the routing on this one. Where do you guys suggust I buy speedo gears from???? I need to run the 23 tooth gear due to my 4.10 and Ive been buying it from a local Mustang shop here in NC.

 

[jrichker]

Are you running the 23 tooth white gear? The 23 tooth white gear works good for some guys, but self destructs in a few months for others.

 

[Blown331LX]

I most certainll am, I must have the self destructing model that takes the cable out with it ...lol ..... Ive bought the same gear 3 times... The trans is from a 1994 GT with the lower first gear that has had the bell hosing swap to fit my 1990, so the first and only time Ive run the car was with a new white gear and a ADV auto cable. The first fail was my fault cause I assume the cable came prelubed, the next 2 werent. so Im assuming I have a bad speedo cable or gear causing the other to crap out Im just not sure how to know which one. If I do a Ford cable which gear should I go with????????? Im going to have to do process of elimination to figure this out, cause everything else checks out good.

 

[jrichker]

The stock range of speedo gears work correctly with a limited range of tire sizes. The 23 tooth white gear don't seem to be a perfect mesh in some cases, so they chew themselves up in short order.

See Gear Ratio Calc for more help

Check to see if there is a speedometer shop in your area. If there is, ask about the Stewart-Warner speedometer gearbox. I believe it is either a 777 Series Drive Joint Kits and Parts or 666 Series Drive Joint Kits and Parts. It is a small gear box that fits between the speedo pickup gear on the transmission and the speedometer. It has quick change gears that allow you to choose almost any tire size and rear end gear ratio you want. This will allow you to get the accuracy within 1%-3%. The drawback is that it isn't cheap.

Please excuse the typo (theirs, not mine) in the following picture - it should read Custom ratio adapters, not Custom radio adapters.

See Speed Correction Devices (Ratio Adapters) for more info.

 

[Blown331LX]

UPDATE....... So I decided to fool around with this car tonight. First let me correct myself and be honest, the cable did not appear as it broke this time. I assumed it did since it did the past 2 times. I think all the problem is in that bull**** after market gear. I pulled the trans end of the cable out to check it and the gear is chewed all to hell on half of the teeth just as always but with the gear removed I can hand spin the cable and my girl friend can watch the speedimeter move up to about 20 mph. See the attached pic, I know it sucks but at least it shows something. Im thinking of putting the stock red gear out of the 95 car back in it and just calculate how far off it is and deal with it. The stock plastic or whatever its made of gear has lasted for 100,000 + miles without any issues. So I WILL NOT BE BUYING ANY GEARS LIKE THAT WHITE ONE AGAIN. Aparently they are either made incorrectly or my trans doesn't like them, and Im very curious to see HOW MANY OF YOU Have had the exact same issue with them??? If so we should all ban them cause theyre and agrivation, waste of time and money. Jricker, I do appreciate your abundance of knowledge as usual but Im not looking to spend a bunch of money fixing this, do you know of any other suppliers or manufactures or the 23 tooth gear?????????? What do you run and how much did it cost???????

 

[jrichker]

I have heard that Jeeps use a 23 tooth white gear. A Google search might turn up a part number, or check out the nearest Jeep dealer.

 

[BlownFiveLiter]

The 23 tooth Chrysler/Jeep gear is the one that usually gets chewed up. The pitch is different than the gear inside the trans, so it ends up wearing out.

 

[FastDriver]

I've had this problem many times. Never looked for a permanent solution. I just keep replacing the gear.

I guess my BS3 will fix that problem because I'll be going with a driveshaft speed sensor. So no more worrying about new gears or cables, but that's outside the realm of feasible for those who don't already have a similar stand-alone.

Chris

 

[capriman86]

Here is what I noticed on a friends car and I still have to get back there to replace it but....


When you put the speedo gear on the cable, did it seat down easily or did you have to push it on and compress the cable a bit to get the clip on?

On my buddies car I think we need to trim 1/8th to 1/4 inch off the squared cable end so it will seat nicely in the gear. There is too much tension with it not cut.

Don't know if that is it, but that is what I am trying next on his car.


The other odd thing is that the gear he has in his tranny now is one from an AOD with the longer snout....which accepts the longer cable end.

The black one is what he needs and its too tight on the cable. The speedo cable is the correct one for his car too.

 

[Blown331LX]

The 23 tooth Chrysler/Jeep gear is the one that usually gets chewed up. The pitch is different than the gear inside the trans, so it ends up wearing out.

Think this dude is selling me Chrysler gears??? I have also heard that there is about an 1/8' to 1/4" difference in cable length between the auto and 5spd as well as the gear, could it be Im simply getting the wrong parts?