Rum, rum, rum@ 3,500 RPM
My E450 with V10 has a slight surging of RPMs at 3,500 and climbiing hills. Normal or something out of balance? New 8 months old 2015 chassis.
Forum Discussion
What I'd do is try to duplicate it on flat land or convenient hill and once you're able to take it to Ford under warranty. If it is totally RPM related will it do it in park revved up to the noted RPM? These kind of problems are hard to solve remotely.
From what you're writing, it could be an engine surge/misfire, defective torque converter, bad bearing in transmission, fan issue, driveshaft issue, exhaust resonance or contact issue, coach box resonance or mounting issue. The degree of the issue is important. Time to get someone to listen to it. Solving this online will be difficult. Your best effort will be trying to find a way to duplicate it in ordinary locations and circumstances so others can diagnose. You may need to manually hold various gears/RPM and accelerate through the speed range.
And to reemphasize: Big box on E450 will have it's share of noises and other oddities. There is a point where stuff is harmless and can be ignored. Have someone listen to it.
From what you're writing, it could be an engine surge/misfire, defective torque converter, bad bearing in transmission, fan issue, driveshaft issue, exhaust resonance or contact issue, coach box resonance or mounting issue. The degree of the issue is important. Time to get someone to listen to it. Solving this online will be difficult. Your best effort will be trying to find a way to duplicate it in ordinary locations and circumstances so others can diagnose. You may need to manually hold various gears/RPM and accelerate through the speed range.
And to reemphasize: Big box on E450 will have it's share of noises and other oddities. There is a point where stuff is harmless and can be ignored. Have someone listen to it.
