CML Service Posted May 23, 2006 Share Posted May 23, 2006 I've been busy lately working on one of my B models. I am trying to get it ready for my son to practice for his CDL and take his test. I need to get the speedo working and I need some help. First off it never worked since I had it (I didn't care). It seems the original owner may have removed the cable and possibly the adapter (it only shows 1 mile). It has a quad trans and I can find the drive but a cable wont fit the pencil gear has a very small square drive. Do I need a adapter ? Any info would be great. Thanks Chuck Quote Link to comment https://www.bigmacktrucks.com/topic/1125-need-speedo-info/ Share on other sites More sharing options...
truxnut Posted May 23, 2006 Share Posted May 23, 2006 About 90% of trucks need a ratio correction [adapter]box to get the speedo to read right. They can be had with the small square drive tip,a .203 round with a tang was used in most Spicer and Fuller. Quote John Evans, Trucks & Dogs are expensive!! Link to comment https://www.bigmacktrucks.com/topic/1125-need-speedo-info/#findComment-5851 Share on other sites More sharing options...
Freightrain Posted May 25, 2006 Share Posted May 25, 2006 Most truck shops have pieces to make speedo cables, with any ends you need. They have the "special" die that makes the end of cable square to fit speedo head.The drive end, like John mentioned might need a "adaptor" to make the speedo read correct. It depends on what's all been changed on the truck(as for rear gear ratios). I got my reducer off Ebay for like $12. Guy sells them on there all the time. You won't know how far off til you get it working and see what the deal is. You won't need the reducer at first, the cable should thread right on to tranny. The keyed adapter(that John mentions) should be available at truck shop. Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment https://www.bigmacktrucks.com/topic/1125-need-speedo-info/#findComment-5887 Share on other sites More sharing options...
CML Service Posted May 25, 2006 Author Share Posted May 25, 2006 Thanks for input folks. It looks like this thing may use a 90 adapter. I had a chance to see another one that was complete. I also checked my line sheet and it looks like it lists some sort of adapter. I guess it isn't as simple as my R model that goes staight in with no adapter. I have a few Mack cables in stock (different lengths) and they have a few different drive ends in a package but this trans has a square the same size as the cable. I think I may have to cut down one that is a little long and get some ends and a ratio adapter. The hardware supplier I use has the cable ends and crimper I just need to check on the adapter. Oh well I guess it's all part of the fun. My highlight tody was when I came back to the barn and found a pair of brand new 11.00R 22 Goodyears my tire man dropped off. Boy do those look impressive. I guess they should for the price. Chuck Quote Link to comment https://www.bigmacktrucks.com/topic/1125-need-speedo-info/#findComment-5890 Share on other sites More sharing options...
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