Harsh downshifts (zf8hp70).

[Zimm]

Does anyone else notice the transmission acting like the tq converter is locking up? the 3-2-1 when decelerating is holding the gears like in tow/haul mode on my f350 diesel. Actually all the time, but it's really noticeable when I'm below 15mph and slowing. It really slows the car down and when it downshifts the release is one perceives the car to accelerating slightly until it hits the next gear. Coming to a stop smoothly is difficult, as modulating the appropriate braking force isn't possible. It's sooooo much smoother to just shift to neutral then back into gear when stopped. It also drones and vibrates when stopped at a light. It's ok when cold, but changes behavior when the fluid starts to warm.

I really have no idea how these operate since it adaptive, and the "reset" theory doesn't do a thing.

Does anyone know much about these transmissions? Is anyone else experienceing this, or do I just have something unique happening?

 

[Phred]

Yeah, it seems very difficult to time on the low end. I’m having the same issue when coming to a stop in traffic…it seems like it hesitates, or surges a bit, or dies off…you never know what you’re going to get.

Drones and vibrates too. It seems like it wants to take off when stopped…like nervous hesitation.

Really weird for sure…

I am putting in an iopedal that will hopefully help, we’ll see.

 

[Zimm]

Yeah, it seems very difficult to time on the low end. I’m having the same issue when coming to a stop in traffic…it seems like it hesitates, or surges a bit, or dies off…you never know what you’re going to get.

Drones and vibrates too. It seems like it wants to take off when stopped…like nervous hesitation.

Really weird for sure…

I am putting in an iopedal that will hopefully help, we’ll see.

keep me posted.

I may go to a specialist transmission shop or a bimmer shop. I get the feeling the dealer wouldnt know and wouldnt care. I just know, there no way this tranny acts like this in an x7 or even a dodge. something is weird. It wasnt like this when i test drove it.

How is yours when cold?

 

[Phred]

Mine is the same cold or warm.

The engine itself is pretty noisy to the point where it sounds diesel-like in the passenger foot well. Almost like a vibration. I received a loaner from the dealer while mine was in getting a sensor replaced, and it sounded exactly the same.

 

[255/85]

I've casually noticed that ours holds the lower gears when coasting down slight grades with my foot off the accelerator pedal even if vehicle speed increases a bit (we live on a hill). A couple of times the transmission has held a gear until well over 2K rpm. The engine sound is very noticeable with lots of exhaust burbling but I wouldn't classify it as sounding like a diesel engine.

At stops it will downshift all the way to 1st gear now. It would only drop to 2nd in the beginning and require manual mode to access 1st gear.

 

[Zimm]

I wonder what sort of internal mayhem they specced for this use that ruins its smooth nature and is generally unneeded.

I've casually noticed that ours holds the lower gears when coasting down slight grades with my foot off the accelerator pedal even if vehicle speed increases a bit (we live on a hill). A couple of times the transmission has held a gear until well over 2K rpm. The engine sound is very noticeable with lots of exhaust burbling but I wouldn't classify it as sounding like a diesel engine.

At stops it will downshift all the way to 1st gear now. It would only drop to 2nd in the beginning and require manual mode to access 1st gear.

 

[Zimm]

There are temp sensors for the fluid, and I’m curious if it’s a program that kicks in at operating temp.

 

[255/85]

I wonder what sort of internal mayhem they specced for this use that ruins its smooth nature and is generally unneeded.

It may be due to the learning mode (or whatever its called). We're rather conservative when driving the vehicle as it's still quite new to us. For urban driving high range 1st gear seems much too low †o use when racing stoplight to stoplight but is about perfect when used off highway in non-critical situations. I like the refusal to automatically upshift when I'm not demanding increased speed even though there would be fuel savings. It's not as predictable as true manual mode but give it some go pedal and it happily bumps up the gearing.

 

[Phred]

IOpedal installed and it defiantly helps smooth the throttle response out. No more lag at starts…very peppy.

Only took a quick drive to make sure it was working.

 

[Zimm]

IOpedal installed and it defiantly helps smooth the throttle response out. No more lag at starts…very peppy.

Only took a quick drive to make sure it was working.

off topic but, I'd prefer a much longer pedal travel offroad. I made an adjustable linkage on my fj60 so throttle tip in off road is sloooooowwwww. Is that possible with a devise like this?

 

[Tazzieman]

off topic but, I'd prefer a much longer pedal travel offroad. I made an adjustable linkage on my fj60 so throttle tip in off road is sloooooowwwww. Is that possible with a devise like this?

Yes. With this device there are modes for all situations. Scroll down; anti slip mode

evcX Throttle Controller to suit INEOS GRENADIER 2022 - ON

EVC evolved, EXPLORE the power of your vehicle with the wireless-enabled evcX Throttle Controller. Features: • App controlled• Ultimate9 TC app - iOS/Android compatible• 8 Driving modes, 32 levels of adjustability• Lock Mode• 10-minute installation, 100% plug & play• Removable user interface...

www.ultimate9.co

 

[Phred]

The iOpedal doesn’t have as many levels as what Tazz shows. It has 4 modes with 5 levels in each mode.

Based on what you’re looking for in a softer delivery of power, you’d probably go with Eco mode see the snap below that I took from the manual.

 

[HereinDaRockies]

I notice the same lurching shifting coming to a stop.

Have anyone also sensed a pattern of weird feeling accelerating away from a full stop?

Most cars when I let go of the brake, the car starts to creep forward. Application of gas propels it further.

With the IG, letting go of the brake does not allow the vehicle to creep forward. Application by of gas is followed by a slight “clunk” almost feels like the auto vehicle hold feature that some vehicles have.

I’d like to achieve that smooth take off from full stop. However I am starting to detect this slight clunk

 

[Mad Hatter]

On mine if the motor and trans are cold it hardly creeps but once warmed up it creeps as you would expect it to. Also with reference to the original post, mine is very smooth on both upshifts and downshifts, and I’ve noticed that if you are cruising to a gentle halt the motor does a little auto-blip on each downshift to ease the transition, it’s subtle but definitely there.

 

[Zimm]

Thanks. Mine is craptastic. I get irritated after a short bit and now I shift to neutral when slowing.

 

[255/85]

Ours has very occasionally had a slightly abrupt downshift into 2nd gear when coming to a stop. It hasn't happened often enough for me to make any mental note to monitor it.
I'm wondering if it may be occurring when easing up on the brake pedal just before coming to a complete stop? I was taught to do this to dissipate momentum and prevent lurching and rebound. Maybe the DME gets confused when I lift my foot and thinks I'm about to accelerate?

 

[Zimm]

Ours has very occasionally had a slightly abrupt downshift into 2nd gear when coming to a stop. It hasn't happened often enough for me to make any mental note to monitor it.
I'm wondering if it may be occurring when easing up on the brake pedal just before coming to a complete stop? I was taught to do this to dissipate momentum and prevent lurching and rebound. Maybe the DME gets confused when I lift my foot and thinks I'm about to accelerate?

I kinda wish this just stayed in second or hade a low power slick road setting button for second. Unless tromping it for some reason, second seems perfectly adequate for DD with this motor and gearing.

 

[alex3dworld]

Ours has very occasionally had a slightly abrupt downshift into 2nd gear when coming to a stop. It hasn't happened often enough for me to make any mental note to monitor it.
I'm wondering if it may be occurring when easing up on the brake pedal just before coming to a complete stop? I was taught to do this to dissipate momentum and prevent lurching and rebound. Maybe the DME gets confused when I lift my foot and thinks I'm about to accelerate?

i was about to start a post, i have exactly the same harsh...ish downshifting to second during regular driving on the streets. not all the time. is hard to catch what exactly triggers it.