2006 Engine Braking/Transmission Drag (1 Viewer)

[2000UZJ]

On flat ground, or slightly downhill my 2006 with 294K miles feels like it’s always engine braking when I let off in Drive at any speed, though it's most noticeable at 35MPH+, it slows down much faster than you’d expect. Shifting into neutral allows for a proper "coast", and removes the engine brake feeling. This rules out a brake issue, though I am due for rear brakes soon. Tire pressures have been tested from 35PSI to 45PSI with almost no change in performance. My alignment, specifically toe has been checked as well. All is in-line with OE Specs.

In order to maintain a constant speed, on a slight downhill grade I have to keep my foot on the gas pedal.

I read somewhere that 06-07’s have GPS based engine braking so you don’t speed downhill. Can anybody confirm this? I can’t find the post to confirm but maybe I'm confused with seeing a post in the 200-Series Section.

I appreciate any insight into this, or pointers as to where to look.

 

[excessive]

GPS based engine braking

got any source for this ? never heard of this

 

[2000UZJ]

got any source for this ? never heard of this

I may have them mixed up with the 200's, I know I read it somewhere but I can't recall. My truck just always feels like it has some sort of drag on it going downhill.

Here is a post referencing automatic engine braking, but it doesn't have a source. May need to bust out the owners manual.

automatic downshift on steep grades?

Noticing strange behavior on downhills when braking, I read on a Lexus site that the newer Toyota's have automatic downshifting which does not upshift until you accelerate. Anyone know about this? I will start watching the tach for clues. mudlover

forum.ih8mud.com

Edit: Here is another by @OregonLC , where he references the braking action on the A750F.

Radar Cruise uses engine braking?

First off, I am a huge fan of the radar cruise feature. I have never had it on a vehicle previously and I believe it to be basically witchcraft. Does anyone know if this system will use engine braking to slow the vehicle? It seems to slow down faster than if you were just to take your foot...

forum.ih8mud.com

 

[Live to Ski]

I noticed this too. just wrote it off to the lc gods.

 

[2000UZJ]

I noticed this too. just wrote it off to the lc gods.

I would love to turn this off. Glad you have experienced it as well. I’d prefer to coast rather than be slowed down all the time.

 

[2001LC]

Is this a change in feel, from what it was?
Is this while shifter in D?
Are you sure, CDL is not engaged?

All YES, than here's more?:
Any service work done prior to engine braking feel, including new tires?
Have you check the speeds at which transmission shift up and down into each gear, to see if normal?
Has the breather for transmission been checked?
When, with what A/T fluid, how many qts was A/T flushed with and at what A/T fluid temp was level set.
Been in any deep water since, last A/T flush?
Is the ECT PWR, OFF. Does it's dash light work?
What is engine engine coolant temp (degrees)?
What are the A/T 1 & 2 temps?

 

[2000UZJ]

Is this a change in feel, from what it was?
Is this while shifter in D?
Are you sure, CDL is not engaged?

All YES, than here's more?:
Any service work done prior to engine braking feel, including new tires?
Have you check the speeds at which transmission shift up and down into each gear, to see if normal?
Has the breather for transmission been checked?
When, with what A/T fluid, how many qts was A/T flushed with and at what A/T fluid temp was level set.
Been in any deep water since, last A/T flush?
Is the ECT PWR, OFF. Does it's dash light work?
What is engine engine coolant temp (degrees)?
What are the A/T 1 & 2 temps?

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!

 

[jLB]

I read somewhere that 06-07’s have GPS based engine braking so you don’t speed downhill. Can anybody confirm this?

I’m trying to figure out if you’re trolling here…

 

[2000UZJ]

I’m trying to figure out if you’re trolling here…

Well, no. I stated multiple times that I read that but potentially confused with 200’s, then found some posts and included them.

I wish I was trolling, that would mean I don’t suspect something wrong lol.

 

[YotaWagon]

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!

I want to say that he was asking with the first question: Did the characteristics of your vehicle change at some point?

I've always noticed I need to use the brakes way less than other cars in front of me, and other cars that I've driven.

 

[Live to Ski]

Is this a change in feel, from what it was?
Is this while shifter in D?
Are you sure, CDL is not engaged?

All YES, than here's more?:
Any service work done prior to engine braking feel, including new tires?
Have you check the speeds at which transmission shift up and down into each gear, to see if normal?
Has the breather for transmission been checked?
When, with what A/T fluid, how many qts was A/T flushed with and at what A/T fluid temp was level set.
Been in any deep water since, last A/T flush?
Is the ECT PWR, OFF. Does it's dash light work?
What is engine engine coolant temp (degrees)?
What are the A/T 1 & 2 temps?

I defer in respect to the one who has 13,000+ posts and, i believe, is a professional mechanic. May the force be with you!

 

[Biga27110]

I've noticed on steep grades it will downshift. Essentially if you're braking gently but the mph increases truck will downshift. This doesnt happen on flat ground.

 

[2000UZJ]

I want to say that he was asking with the first question: Did the characteristics of your vehicle change at some point?

I've always noticed I need to use the brakes way less than other cars in front of me, and other cars that I've driven.

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"

 

[YotaWagon]

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 think what you're describing is something I've always thought of as normal in my 06 LC.

When I drive my girlfriend's F-150 it scares me when I let off the throttle because it feels like there's no deceleration. It takes a few minutes of driving to settle in lol

 

[2001LC]

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:

1. Is it normal or and actual issue.
2. Was there any services or changes, before it began.
3. What if any, modification to factory configuration.
4. Are all systems operating, as they should be. Even seemingly unrelated ones.
5. Any DTC current or pending. (Pending's, do activate a CEL)

A few thoughts that come to mind:

1. Excessive pressure in A/T. High fluid or valve issue, come to mind.
2. 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.
3. 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.