Attention: TDR Forum Junkies 
For some reason, it’s beginning to feel like the mighty Cummins is “missing”. At highway speed and without any kind of load, about 65-67 MPH it acts like an old gasser that’s missing, or perhaps like it’s intermittently fuel-starved. However, when I punch it, it just gets up and screams.
Then at lower speeds, say 30-40 MPH, it acts like it’s “surging” – just a momentary RPM flare that seems to have no effect on speed, like the transmission has just slipped. And I occasionally experience transmission hunting at a steady 30-32 MPH on level roadways. But again, when I punch it or put it under a slight load like heading up a hill, it’s got rock-solid power. If it’s working correctly, the BD Pressure Lock should be preventing the slipping, (and perhaps the hunting?).
I have an old VA box on it that I’ve not tried disconnecting yet. I guess some folks have been having problems with VAs giving out? If so, is it a gradual decline, or does it fail completely? I don’t know if this might be a contributor. Nor have I tried disconnecting the PE. I’m not concerned about the scotch-lock since the connection seems to be solid based on the way it pulls when I hit the throttle.
Could the dreaded lift pump failure be a possibility? Again, with no fueling problem at hard throttle, I rather think not, but I’m not mechanically savvy enough to know this for sure.
I’ll be going back to my transmission shop this week to adjust the pressure up a bit. (I’ve never been all that happy with its shifting since the original transmission work anyway. ) Would this make sense? Might this solve the problem, or should I be looking elsewhere for the source?
I’d sure appreciate hearing any ideas about what’s going wrong and what I need to do to fix it. And if all this has been covered before, my apologies, but it’s been difficult finding TDR time with the workload I carry.
Then at lower speeds, say 30-40 MPH, it acts like it’s “surging” – just a momentary RPM flare that seems to have no effect on speed, like the transmission has just slipped. And I occasionally experience transmission hunting at a steady 30-32 MPH on level roadways. But again, when I punch it or put it under a slight load like heading up a hill, it’s got rock-solid power. If it’s working correctly, the BD Pressure Lock should be preventing the slipping, (and perhaps the hunting?).
I have an old VA box on it that I’ve not tried disconnecting yet. I guess some folks have been having problems with VAs giving out? If so, is it a gradual decline, or does it fail completely? I don’t know if this might be a contributor. Nor have I tried disconnecting the PE. I’m not concerned about the scotch-lock since the connection seems to be solid based on the way it pulls when I hit the throttle.
Could the dreaded lift pump failure be a possibility? Again, with no fueling problem at hard throttle, I rather think not, but I’m not mechanically savvy enough to know this for sure.
I’ll be going back to my transmission shop this week to adjust the pressure up a bit. (I’ve never been all that happy with its shifting since the original transmission work anyway. ) Would this make sense? Might this solve the problem, or should I be looking elsewhere for the source?
I’d sure appreciate hearing any ideas about what’s going wrong and what I need to do to fix it. And if all this has been covered before, my apologies, but it’s been difficult finding TDR time with the workload I carry.
