68RFE Downshift

[7.3toreador]

This has been an issue since I bought the truck used with 24K miles. I've been used to manually shifting with tow/haul and the EB on I tried leaving it in 4th while on my way this morning to work. I see the light is red up ahead and take my foot off the pedal and watch the the transmission shift...............sort of. 40 mph, 30 mph, 20mph. Nothing. Between 10 and 15 mph it finally downshifts to 3rd. What is this a symptom of?

 

[CMB]

If your referring to the exhaust brake not working that low, I believe the cut off is around 1500 RPM. I don't think it is a "symptom" of anything. After the stop and you begin to accelerate does it stay in first gear? As long as it's not "lugging" in the wrong gear you're fine.

Maybe I'm not understanding the question.

Cheers,

 

[7.3toreador]

If your referring to the exhaust brake not working that low, I believe the cut off is around 1500 RPM. I don't think it is a "symptom" of anything. After the stop and you begin to accelerate does it stay in first gear? As long as it's not "lugging" in the wrong gear you're fine.

Maybe I'm not understanding the question.

Cheers,

The issue is, and has been, when I decelerate, regardless if the EB is on or not, regardless if TH is on or not; the truck doesn't like to down shift. If I get on the accelerator at 20 and it is still in 4th it doesn't Downshift unless I get into it hard. I have even commanded 3rd in some instances and it will still stay in 4th.

 

[Newsa]

If you want the exhaust brake to work below 30 mph, you need a g56 transmission. I think both cruise control and eb stop engaging around 25-30 mph in the automatics.

 

[gsbrockman]

If you want the exhaust brake to work below 30 mph, you need a g56 transmission. I think both cruise control and eb stop engaging around 25-30 mph in the automatics.

Exhaust brake function is not based on MPH criteria, but engine RPM.

My 2014 and 2018 will exhibit exhaust braking down into 2nd gear (both AS69RC).

 

[CMB]

Sounds like the OPs concern is the lack of down shifting with little to no load regardless if the EB is on and regardless if TH is on. To the point where he needs to downshift manually at certain speeds.


7.3 - do you know what gear ratio you have? I'm assuming you have the stock tie size?

 

[7.3toreador]

I have the 3.42's. No complaints at all on the EB. It gets used judiciously.

 

[Beast2B]

I have found that a gentle touch on the brake pedal seems to command a desire to slow, and will often start the process of downshifting. It doesn't take much, even using the brake pedal to deactivate the cruise.

 

[7.3toreador]

I have found that a gentle touch on the brake pedal seems to command a desire to slow, and will often start the process of downshifting. It doesn't take much, even using the brake pedal to deactivate the cruise.

I dont get any help from the brake either.

 

[Newsa]

https://www.turbodieselregister.com/threads/question-about-exhaust-brake.245692/

 

[Ozymandias]

Just a thought, the transmission has adaptive shifting, if you always shift it manually it will stay dumb.
And as Galen says, it needs a small input from the brake as an input that the driver wants to slow down and not just wants to coast.
To me it would be pretty annoying if the vehicle starts to downshift and brake by just set the throttle to zero.

 

[7.3toreador]

Just a thought, the transmission has adaptive shifting, if you always shift it manually it will stay dumb.
And as Galen says, it needs a small input from the brake as an input that the driver wants to slow down and not just wants to coast.

To me it would be pretty annoying if the vehicle starts to downshift and brake by just set the throttle to zero.

Agreed. I spent a few weeks, painful, after a recall and relearn not manually shifting but the trannybfelt the same.

 

[CMB]

When did the adaptive shifting start? Were there many changes through the years?

7.3,
This might be a silly question but how's the fluid?

 

[7.3toreador]

When did the adaptive shifting start? Were there many changes through the years?

7.3,
This might be a silly question but how's the fluid?

You know, when I 1st bought the truck I brought it to my mechanic and drained all the fluids. transmission, transfer case, diffs etc. After a bit of driving and a top off I have not checked. I will do so tomorrow after my ride to work. About 40 mins mostly highway.

 

[CMB]

Check In neutral at idle