Blue Nile trucker Posted September 19, 2019 Share Posted September 19, 2019 Hey everyone i got 2007 Mack chn613 which came with Mack transmission but I jst swapped it with Eaton transmission everything went smooth but now when I drive it the rpm is very high can’t go no faster than 40 mph what should I do? Quote Link to comment https://www.bigmacktrucks.com/topic/59069-high-rpm/ Share on other sites More sharing options...
Mack Technician Posted September 19, 2019 Share Posted September 19, 2019 (edited) That’s messed up...... you need to work backwards and figure out what your transmission is in terms of model and what your top ratios are....list your trans model and diff ratio and tire size on the thread. Someone will do your calc. Edited September 19, 2019 by Mack Technician Quote Link to comment https://www.bigmacktrucks.com/topic/59069-high-rpm/#findComment-432390 Share on other sites More sharing options...
Maxidyne Posted September 19, 2019 Share Posted September 19, 2019 1 hour ago, Blue Nile trucker said: Hey everyone i got 2007 Mack chn613 which came with Mack transmission but I jst swapped it with Eaton transmission everything went smooth but now when I drive it the rpm is very high can’t go no faster than 40 mph what should I do? Put a Mack transmission back in. Quote Link to comment https://www.bigmacktrucks.com/topic/59069-high-rpm/#findComment-432393 Share on other sites More sharing options...
JoeH Posted September 19, 2019 Share Posted September 19, 2019 Shift to a higher gear?... Quote Link to comment https://www.bigmacktrucks.com/topic/59069-high-rpm/#findComment-432440 Share on other sites More sharing options...
wilbur Posted September 19, 2019 Share Posted September 19, 2019 Any trans will go over 40mph Are you sure its going into high range.? Quote Link to comment https://www.bigmacktrucks.com/topic/59069-high-rpm/#findComment-432446 Share on other sites More sharing options...
david wild Posted September 20, 2019 Share Posted September 20, 2019 Put a Mack back in, best thing he ever did was take the Mack out, just needs to find out what he messed up, maybe a underdrive now he is in direct, or .83 and had a Mack 5/6 speed never said what trans he took out, could be running 5. something ratio and a Fuller with direct or ? would give him no roadspeed. Quote Link to comment https://www.bigmacktrucks.com/topic/59069-high-rpm/#findComment-432476 Share on other sites More sharing options...
Brian L Blaylock Posted September 20, 2019 Share Posted September 20, 2019 You might need a different speedometer adaptor 1 Quote Link to comment https://www.bigmacktrucks.com/topic/59069-high-rpm/#findComment-432477 Share on other sites More sharing options...
JoeH Posted September 20, 2019 Share Posted September 20, 2019 It's gotta be getting to high range to hit 40 mph. We have no idea what trans came out and what went in. He may be clueless on the shifting pattern. But unless he comes back here were all shooting in the dark. He's probably already figured it out. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/59069-high-rpm/#findComment-432494 Share on other sites More sharing options...
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