6.0 intermittent shift issues
6.0 intermittent shift issues
2003 6.0 auto trans 112k miles, does do some snow plowing in the winter.
1. Truck does have a boost leak, has been too cold to fix it, maybe this is the cause but I’m seeing what people think.
2. When first started it won’t engage in drive or reverse unless I tap the throttle and then it jumps forward. After this hiccup happens it doesn’t do it again till the next cool down and start cycle. It was also shifting odd, like slipping a little and would come out of gear sometimes, a little low on power like something is lugging the engine but it doesn’t feel like the boost leak,and it didn’t do that today just the engagement issue.
3. Range sensor is working properly it matches the shift letter, no codes besides turbo boost. 13.8 volts, 47.5-48.5 FICM, Batteries recently died and had to be jumped.
1. Truck does have a boost leak, has been too cold to fix it, maybe this is the cause but I’m seeing what people think.
2. When first started it won’t engage in drive or reverse unless I tap the throttle and then it jumps forward. After this hiccup happens it doesn’t do it again till the next cool down and start cycle. It was also shifting odd, like slipping a little and would come out of gear sometimes, a little low on power like something is lugging the engine but it doesn’t feel like the boost leak,and it didn’t do that today just the engagement issue.
3. Range sensor is working properly it matches the shift letter, no codes besides turbo boost. 13.8 volts, 47.5-48.5 FICM, Batteries recently died and had to be jumped.
Might be worth it to pull pan. Filter could be clogged or sucking some air... but I doubt it
might be worth pulling valve body, checking epc and the pressure valve too...
might be worth pulling valve body, checking epc and the pressure valve too...
Last edited by runthatjunk; Jan 28, 2026 at 09:13 PM.
I changed fluid and filter, ohmed out solenoids and they were good, I also supplied 12v to epc a few times. Now it hasn’t had an issue all week until today, and I think it’s because the fluid level settled and is low. I added more fluid and will update if the issue continues.
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