Put Trans in Neutral won't shift till stop

[shaodome]

If I put the shifter in neutral on my 4L80e, which is the same input pattern as PARK and is setup per the docs.....I can't put the car into any forward gear again until I come to a complete stop.

Using the ratchet shifter and going anywhere between 1-4 gears while moving works fine, but if I put it in neutral while rolling and then back into gear, I get no engagement. I'm wondering if that has something to do with the min/max speeds per gear?

[Bernard Fife]

Shoadome,

This could be for a number of reasons (including things like over/under rev protection, etc.). Do you have a log and an MSQ?

Lance.

[shaodome]

In driving the car to acquire the datalog for this thread, it did something else weird. The "target gear" got stuck and stayed at ZERO, thus the car wouldn't shift. I had to come to a complete stop, but the shifter in neutral and then back to Drive. That "unstuck" the target gear and I was able to continue driving.

In the stuck target gear log, you can see this behavior around 400 seconds into the log.

For the shift to neutral log, jump to 756 seconds and you will see where I put the car in neutral at speed and then attempted to go back into gear. Target gear gets stuck again at zero.

The trans is a 4L80E

[Bernard Fife]

Shaodome,

I will have a look.

Can you remind me why you are putting the car into neutral at speed? The code certainly doesn't anticipate anyone doing this, so I'm not surprised it handles it badly. When I better understand why one might do this, I should be able to alter the code to handle it.

Lance.

[shaodome]

The car has a ratchet shifter for starters, so ending up in neutral can easily be accomplished.

In a racing situation, some might prefer to pop trans into neutral, thus letting the engine idle as opposed to either engine braking (ie, shifter in 3rd gear) or the trans shifting to overdrive when you let off the throttle.

Any idea about the target gear getting stuck? That has happened to me several times now.

[Bernard Fife]

some might prefer to pop trans into neutral

Shaodome,

The reason I ask is because it is illegal in most jurisdictions to coast in neutral on a highway. Does anyone else do this at the race track? If so, could they comment here so we can get a broader perspective? I need to know if this is a common (or recommended) practice, or if it is a rare thing. The code has been designed to generally see neutral as stopped (a sort of 'soft reset'). I can change probably change that, but it will mean less certainty for the code on other fronts, so I only want to do this if it is useful to a number of people, and doesn't mess up a lot of other things (maybe a user option to 'allow neutral at speed').

I looked at your stuck gear log - nothing jumped out at me. There have been a number of changes in this area of the code recently. Have you tried a more recent code version (you appear to be using 4.139, the latest release is 4.145), like this: viewtopic.php?f=4&t=889#p4726 ? Even if it doesn't solve your problem directly, this code has more diagnostics in a datalog so it should be easier to sort it out.

You might also try 'Ignore Lever Errors' under 'General Settings -> Error Behavior -> Lever Error Delay'. And you could try changing the 'Shift Input Pattern -> Lever and Shift Buttons Configuration -> Max. Lever Position Change' to 4.

Lance.

[shaodome]

I'll give your two error handling suggestions a try and see how it goes. I was also thinking about going back to the latest 5.X code so I don't have to worry about the flash burn corruption issues as much. Thoughts?

[Ap67et10]

I have had this happen many times while driving my truck. I have a Lokar shifter that has a reverse detent, but can be pushed directly into neutral (like most all cars with a floor shifter). Currently I use the shifter manually if I want to select and hold a gear. I do not have padel/button shift set up yet. However I have on a few occasions accidentally pushed the shifter into neutral and ran into the same problem. It actually happened to me getting on the freeway one day, and I almost got stuck in the middle of the highway because it would not engage any gears without coming to a stop. In my opinion this is a major safety issue that needs to be changed.

I know some people would shift to neutral on purpose, which I have seen before. I don't tend to do that, but also have done it for various reasons when driving. However more than that, I would say it is the accidental shift to neutral that is the real issue here. There are many reasons a car can accidentally be engaged into neutral and requiring a stop to get any engagement back is a big problem and huge safety concern.



Andrew

[Ap67et10]

Also, I currently have the settings in gpio to ignore lever errors and no rpm checking. I still get random issues (typically if I manually select a gear and hold it for a long period of time) when I go to shift and it'll disengage as if I shifted to neutral. I then have to find a place to stop, cycle the shifter and can then accelerate again.



Andrew

[gui67]

I had the same problem some time ago. we discussed about it on the 4L80e thread. the issue was solved with the 4.143 code for me.
I also have a ratchet shifter that I accidentaly shift to N while cruising.