My tranny shifts true and positive if I shift manually with shifter lever. In drive it hits 3rd too quick and OD doesn't shift right either unless I turn it off then when ready turn it on. No slip no shudder just incorrect shift pattern and timing. First time Cummins owner so be kind LOL 94 300K 3500 AUTO

 

It sounds like your TV cable might be out of adjustment, or your TPS sensor could be worn out. You can web search the testing/adjustment process, if it turns out to be improper TPS voltage sometimes you can monkey the calibration back into spec, if not you might be better off deleting the TPS entirely as the delete kit is a lot cheaper than a new one.