Kurzhaar Posted November 9, 2019 Share Posted November 9, 2019 Last night when returning to the field I flipped the switch to go to look range to downshift and got a grinding noise. Now the truck shifts into gear but the driveshaft does not turn. How can we diagnose this in the field? Quote Link to comment Share on other sites More sharing options...
Popular Post Mack Technician Posted November 9, 2019 Popular Post Share Posted November 9, 2019 (edited) Is it a Mack Transmission? (go ahead Mr.Wild, say it or it’ll fester-up inside and make you sick) Run your air pressure max (120-13Opsi). Dump transmission oil and open the large window cover at the rear box of transmission. Observe rear trans box while an operator is shifting the range up and down between HI and Low range. See what you have..... If you want some live action take the operators keys, put them in your pocket, and have him use a turning tool in the engine flywheel to rotate the engine while you watch the disconnect. Edited November 9, 2019 by Mack Technician 1 1 1 Quote Link to comment Share on other sites More sharing options...
fjh Posted November 9, 2019 Share Posted November 9, 2019 (edited) Tech BE NICE now 😂 ! If it is a mack trans it sounds like it is You could have ! A loose trans yoke bolt check that first ! if its tight the trans lid has to come off to check to see that the shift rail bolt has not come loose! Not a field fix! Chances are the range pack is worn now eitherway the trans needs the back section off it and repaired and unless you got tools for the job you can't do it inframe Trans has to come out!😒 Wild can take over from here. Poke poke jab😀 don’t worry buddy your not alone! Edited November 9, 2019 by fjh 1 1 Quote Link to comment Share on other sites More sharing options...
Kurzhaar Posted November 10, 2019 Author Share Posted November 10, 2019 23 hours ago, fjh said: Tech BE NICE now 😂 ! If it is a mack trans it sounds like it is You could have ! A loose trans yoke bolt check that first ! if its tight the trans lid has to come off to check to see that the shift rail bolt has not come loose! Not a field fix! Chances are the range pack is worn now eitherway the trans needs the back section off it and repaired and unless you got tools for the job you can't do it inframe Trans has to come out!😒 Wild can take over from here. Poke poke jab😀 don’t worry buddy your not alone! It is an Eaton Fuller 9 speed. Quote Link to comment Share on other sites More sharing options...
theakerstwo Posted November 10, 2019 Share Posted November 10, 2019 On a eaton it sounds like a broken syncro pin that has lodged between the syncros keeping the sliding clutch from going in gear.Make sure you have good air to the range cylinder and if so pull back box.If you find a syncro pin broken then look for a drive line virbration. 1 Quote glenn akers Link to comment Share on other sites More sharing options...
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