alcoon61 Posted September 1, 2010 Share Posted September 1, 2010 I just purchased this Mack a few weeks ago and am encountering some type of electrical problems. My speedometer will start going crazy while going down the road and kick out the cruise control. Using the accelerator when this happens the truck will run fine. Sometimes the warning light stays on for a while and I can hit the brake momentarily and it will shut it off. This problem is intermittent. I have managed to learn to decipher the code and it is a 4.1. Yesterday it ran fine all morning and I ran into a little shower and then it started really acting up. Speedometer going stupid and cruise would not hold for 5 miles. I think it is a sensor problem or something loose. Can anybody tell me where to start looking? I also have a abs light that comes on sometimes and sometimes it stays out for days. Thanks! Quote Link to comment Share on other sites More sharing options...
rhasler Posted September 1, 2010 Share Posted September 1, 2010 I just purchased this Mack a few weeks ago and am encountering some type of electrical problems. My speedometer will start going crazy while going down the road and kick out the cruise control. Using the accelerator when this happens the truck will run fine. Sometimes the warning light stays on for a while and I can hit the brake momentarily and it will shut it off. This problem is intermittent. I have managed to learn to decipher the code and it is a 4.1. Yesterday it ran fine all morning and I ran into a little shower and then it started really acting up. Speedometer going stupid and cruise would not hold for 5 miles. I think it is a sensor problem or something loose. Can anybody tell me where to start looking? I also have a abs light that comes on sometimes and sometimes it stays out for days. Thanks!The speedometer sensor is on the output bearing housing of the transmission. If you have a Mack transmission the sensor should be screwed all the way against the yoke and then backed out one full turn. Do not overtighten the jam nut on the sensor (15 ft lbs. max) as it will crack the outside of the sensor. If you have a Mack transmission make sure that the yoke retaining bolt is not loose or missing. Quote "Mebbe I'm too ugly and stupid to give up!" Link to comment Share on other sites More sharing options...
alcoon61 Posted September 1, 2010 Author Share Posted September 1, 2010 The speedometer sensor is on the output bearing housing of the transmission. If you have a Mack transmission the sensor should be screwed all the way against the yoke and then backed out one full turn. Do not overtighten the jam nut on the sensor (15 ft lbs. max) as it will crack the outside of the sensor. If you have a Mack transmission make sure that the yoke retaining bolt is not loose or missing.It has a 13 speed eaton fuller tranny. Quote Link to comment Share on other sites More sharing options...
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