IH Farms 2 Posted April 7, 2014 Share Posted April 7, 2014 I'M looking for possible causes for it not working on a truck I'm looking at to get an idea what I'm getting into. Is it a cable or sensor or wiring? It has a mack 9spThanks Quote Link to comment https://www.bigmacktrucks.com/topic/35323-speedometer-not-working-88-mack-superliner/ Share on other sites More sharing options...
MHfred Posted April 7, 2014 Share Posted April 7, 2014 I had to trouble shoot the mechanical speedo on on my MH. I would start by putting a drill on the cable at the transmission. I think I had to run my drill in reverse to show speed. That should give you a starting place. Quote Link to comment https://www.bigmacktrucks.com/topic/35323-speedometer-not-working-88-mack-superliner/#findComment-240999 Share on other sites More sharing options...
IH Farms 2 Posted April 7, 2014 Author Share Posted April 7, 2014 Ok. So it's a good possibility that the cable is just broke I'll look into it going to pick it up this Saturday at least that's the plan as of right now Quote Link to comment https://www.bigmacktrucks.com/topic/35323-speedometer-not-working-88-mack-superliner/#findComment-241000 Share on other sites More sharing options...
BAD DOG Posted April 7, 2014 Share Posted April 7, 2014 Pretty simple it can only be one of 3 things Cable, Speedo Drive at Tranny or the Speedo itself. All are pretty cheap to do. I'd check the cable first. Quote Link to comment https://www.bigmacktrucks.com/topic/35323-speedometer-not-working-88-mack-superliner/#findComment-241042 Share on other sites More sharing options...
rsb502 Posted April 7, 2014 Share Posted April 7, 2014 actually I just take the cable off the back of the speedo and try to turn it by hand if you can the cable is probably bad, more times than not its the little plastic adapter on the end not the cable, I keep spares in the garage. other than that if its good keep it out and move the truck down the driveway, the cable should turn if it does the speedo is probably the culprit, the drill works too but most of the time its the adapter or speedo so you gotta take the dash apart anyway so I just start there. Quote "Any Society that would give up a little LIBERTY to gain a little SECURITY will Deserve Neither and LOSE BOTH" -Benjamin Franklin"If your gonna be STUPID, you gotta be TOUGH" "You cant always get what you want, but if you try sometimes you get what you need" Link to comment https://www.bigmacktrucks.com/topic/35323-speedometer-not-working-88-mack-superliner/#findComment-241048 Share on other sites More sharing options...
Deere Mack Posted April 7, 2014 Share Posted April 7, 2014 I've been having a similar problem with my 6 spd mack. Visit this thread for some photos that might help you out. Good luck! I'm still scratching my head on mine.http://www.bigmacktrucks.com/index.php?/topic/35290-trxl-107-speed-cable-adapter/ Quote Link to comment https://www.bigmacktrucks.com/topic/35323-speedometer-not-working-88-mack-superliner/#findComment-241055 Share on other sites More sharing options...
2stacksuperdog Posted April 8, 2014 Share Posted April 8, 2014 We have put 3 speedo's in our superliner within that last 4 years. Finally put cable speedo and used a steel adapter. Should be good now. 1 Quote Matt Link to comment https://www.bigmacktrucks.com/topic/35323-speedometer-not-working-88-mack-superliner/#findComment-241058 Share on other sites More sharing options...
IH Farms 2 Posted April 8, 2014 Author Share Posted April 8, 2014 Thanks a lot should be picking it up Saturday going to bring the gps to know how fast I'm going and will let you know when I figure out the culprit most likely I'm thinking the adapter because it has a newer speedo in it only 91k according to it guy says whole truck has 600k and it looks like it's been well cared for Quote Link to comment https://www.bigmacktrucks.com/topic/35323-speedometer-not-working-88-mack-superliner/#findComment-241076 Share on other sites More sharing options...
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