Just the person that I was looking for
Answering them in the order you have.
- There is no change in feel if the engine/trans is cold, or hot.
- Shifter is in "D"
- CDL is not engaged, verified by cycling and no binding on pavement present.
- No service work in the past year, besides an oil change and alignment (toe was within spec, which was my original suspicion having toe in/out creating drag)
- Shift speeds, and smoothness seems to spec. It does not slip, nor short shift / late shift under normal or hard driving.
- Transmission fluid is due for a change, but not critical. Unsure of what is currently in it. PO flushed it regularly at a dealership in CO, rather than drain and fill. I am unsure of the brand/type.
- No water crossings
- ETC is selected at random times. The light does work but the behavior does not change in regards to the "drag"
- Coolant is within spec, I believe my OBDII reader shows ~192-198*F once warmed up.
- I do not have the ability to check AT Temps.
Thanks for posting up!
Ah, good catch. No, it's always been the same but I have become more aware of it in the past few months. It wasn't until the other week that I started playing around with shifting into "N" and seeing the speed increase vs decrease in "D"
I don't know how much, help I can be! As I've not dealt with the issue.
First, is what you're feeling, normal or some malfunction.
When we're accelerate and let off gas, we feel the lose of inertia. This is not same as engine braking, but feels like it.
Engine braking, is second nature to me. If you follow me, while descending mountain passes. You'll not likely see my brake lights come on. Yet my speed will hold constant on descents or even reduce. My right hand, is almost always resting on the shifter. I'll even use engine braking, for great stopping power. Down shifting to L during hard braking, to stop.
OM shows engine braking, in 4,3,2,& 1. I hadn't notice this before, that is does not indicating engine braking in D. I engine brake so often, by down shifting. It just second nature to me. I'll need see what happens, to RPM/MPH in D. Like when accelerating, and letting off gas just before shift point while I D.
We can downshift at any speed, to as low of a gear as we like. We can be going 100 MPH, and shift down to L. Nothing will happen. Until speed drops to range of 4th, than we feel sudden hard engine braking. At that point, RPM will jump higher (foot of gas pedal) as MPH/speed drops. Than when in 3rd speed range, transmission shift to 3rd. And so on, down to L range. We need to be aware, this sudden hard a fast slowing as we speed hit range, of next gear down. This can and will affect handle. If on slipper road condition (ice, snow wet, sand, etc..), we can skid spin or loose control.
"If" engine braking, not suppose to happen in D. We'd have no actual engine braking feel. Coasting in N, form cruising (not accelerating) while in D and then letting off gas. We'd feel little if any. In both case speed would drop about same rate.
Assuming you've and issue, and not just a normal condition felt when letting off gas while in D.
How I look at mechanical issues:
- Is it normal or and actual issue.
- Was there any services or changes, before it began.
- What if any, modification to factory configuration.
- Are all systems operating, as they should be. Even seemingly unrelated ones.
- Any DTC current or pending. (Pending's, do activate a CEL)
A few thoughts that come to mind:
- Excessive pressure in A/T. High fluid or valve issue, come to mind.
- Not actual in D or data fault. If engine braking not suppose to happen in D. I would think you'd notice shift points, not as they should be while in D.
- Some electric fault, result in transmission not actual or knowing it is in D. Allowing engine braking. But again here. I'm unsure at this point, is this by design, that we can't engine brake in D.
History of full flushes is good. But, you do not know with what A/T fluid or if level correct. I've solved, a lot of transmission issues. By flushing with proper ATF and setting to proper level. A/T fluid level, is temp dependent. Often, when history shows "Flush". It's actually drain and fill. Additionally when transmission cooler lines removed from radiator, fluid lost. Some top with who knows what, without properly setting level by temp of fluid.
BTW: I've the OBDIImx, for iphone. It's just one, of many available in the market. It, allows most anyone's software be used on it. I can read and log all tech stream data. i.e. A/T temp, ECT, CAT, fuel trims, RPM, MPH, etc. in real time.
Here's a screen shot of just one of my "Dashboards" I set up.: Not only great for diagnostic work. But very handy, while setting A/T fluid level.
The few rigs, I felt, what seems to be extra drag or engine braking. They gave me impression of a heavy feel. Which they were, heavy built with large tires. They also has aftermarket wiring, wiring in of toys. And or, modifications to factory systems. Like AHC delete, Hewitt block-off kit, NAV or radio upgrades, etc. Perhaps I miss read those, and need to pay more attention.
