6MT 3rd Gear Power Interruption

[JTDay]

Just looking to see if anyone else has experienced this. I have a 2022 with about 1000mi on it. I won't go as far to say it's an "issue" but it seems a little odd. I found a post on another forum which describes the event in identical detail as I have experienced it (screenshot below). Essentially, shortly after engaging 3rd gear and when beginning to accelerate, I feel what seems like a single, pretty mild but noticeable, "jerk". No idea if it's engine control or driveline related. Anyone else experience this?

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[SteveInOrlando]

Yes, there is a noticeable dip in the power curve where you describe. Those of us with Superchargers can attest.

The issue is with the default tune. It thinks you are getting too much power too quickly and dials back the power. Part of that whole torque management power system.

If you were to look at the tables feeding that, they actually have that dip in the base throttle management maps. No idea why.

 

[JTDay]

Great explanation Steve. That's how it feels. Like the throttle plate snaps shut or almost shut for a split second in that range. I guess the solution for now is to shift into 3rd a bit later. I need to grab a logging device and figure out how to look at sensor data.

 

[hjdca]

I have a 2020 JTR manual transmission with almost 40K miles., and I do not have this issue. You can powershift it into 3rd and lurch forward or easy shift it to 3rd. There is no loss of power anywhere in the powerband in 3rd. I also run trails in 4Wheel Low in 3rd gear with the clutch out and even at super low RPMS, I have never felt any power disruption.

Note: I will drive it with special attention to this and see if my 2020 JTR has it.

 

[JTDay]

The feeling is more of a HARD misfire or the throttle plate slamming closed for 0.20 seconds. Its not a gradual or mild loss of power but a single, abrupt jerk/bump type sensation. If I'm hard on the gas in 2nd and into 3rd, it doesn't happen. If I accelerate at a snails pace from 2nd to 3rd it doesn't seem to happen. It only happens when short-shifting from 2nd to 3rd at low RPMs. The other guy's thread I pasted from another forum describes the occurrence identical to mine. I need to figure out how to log fuel stuff and throttle body position and maybe that will tell me something.

 

[TroutFishingInAmerica]

I haven't noticed this issue BUT I don't shift from 2nd to 3rd at 1,700 rpm either, I twist it up higher. Sooo, I went for a drive and attempted it, short shifting 2nd to 3rd, I got the results you described. Not just a little bit but very noticeable. I have a Sprint Booster (pedal controller type thingy) that is currently removed, I'm thinking about reinstalling it and seeing if it makes a difference. It's below freezing right now but should warm up in a few days. It would be interesting to hear if others experience with the different pedal controllers.

 

[JTDay]

Thanks for going out and trying that. It seems odd that the engine doesn't lug or seem to mind short shifting into 3rd with the exception of the "jerk" that occurs.

I'd considered buying one of the throttle controllers. If you test your hypothesis, let us know the outcome.

 

[JTDay]

Diverging on my own original topic here a bit, but does anyone else experience a pretty audible gear/transmission whine in 5th and 6th at highway speeds with their 6MT? The whine is present during steady state cruising as well as accel and decel in 5th/6th at highway speeds. The whine is NOT present in 1-4 or any speed below ~65mph. The only thing I could find on this was for some people who had regeared and experienced a new whine.

 

[OHJeeper]

Essentially, shortly after engaging 3rd gear and when beginning to accelerate, I feel what seems like a single, pretty mild but noticeable, "jerk". No idea if it's engine control or driveline related. Anyone else experience this?

+1

I noticed this in my 2018 JTR and it appears to have carried over to the 2022 JTR as well. I've seen numerous posts on this on a few different forums.

@DAVECS1 , is this something your tune (either NA or SC) helps (or can help) with?

 

[NachoRuby]

I feel what seems like a single, pretty mild but noticeable, "jerk". No idea if it's engine control or driveline related. Anyone else experience t

I've noticed it a couple of times if I'm cruising at a constant speed in 3rd, or mild acceleration, but never at hard acceleration. It's usually my cue to change gears when it does happen

Diverging on my own original topic here a bit, but does anyone else experience a pretty audible gear/transmission whine in 5th and 6th at highway speeds with their 6MT? The whine is present during steady state cruising as well as accel and decel in 5th/6th at highway speeds. The whine is NOT present in 1-4 or any speed below ~65mph. The only thing I could find on this was for some people who had regeared and experienced a new whine.

No. Not at all. What speeds in 5th and 6th are your highway speeds?

 

[JTDay]

I've noticed it a couple of times if I'm cruising at a constant speed in 3rd, or mild acceleration, but never at hard acceleration. It's usually my cue to change gears when it does happen


No. Not at all. What speeds in 5th and 6th are your highway speeds?

This is a bit of a guess, but 55+ in 5th and 70+ in 6th. I don't really use 6th unless I'm doing over 70. Thanks for the response. The whine doesn't seem normal.

 

[NachoRuby]

This is a bit of a guess, but 55+ in 5th and 70+ in 6th. I don't really use 6th unless I'm doing over 70. Thanks for the response. The whine doesn't seem normal.

Might just want to check your rear diff. With all the leaking ones out there, just to make sure it's not low, because that would cause a whine, although that'd have to be a major leak. Of course, you can check the trans fluid level too, but that's as far as I'd go diagnosing on a brand new vehicle before i schedule a dealer visit.

 

[SteveInOrlando]

The feeling is more of a HARD misfire or the throttle plate slamming closed for 0.20 seconds. Its not a gradual or mild loss of power but a single, abrupt jerk/bump type sensation. If I'm hard on the gas in 2nd and into 3rd, it doesn't happen. If I accelerate at a snails pace from 2nd to 3rd it doesn't seem to happen. It only happens when short-shifting from 2nd to 3rd at low RPMs. The other guy's thread I pasted from another forum describes the occurrence identical to mine. I need to figure out how to log fuel stuff and throttle body position and maybe that will tell me something.

ok, I misunderstood what you were describing. I have experienced what you are talking about, but I would have thought it was a problem mainly for boosted vehicles.

if your truck is unmodified I would suspect there is an issue. I would try to figure out how to duplicate it, then take it to the dealership.

When you look at my power curves going into 3rd gear, I get a nice steady power rise, then a sudden drop and a hard jump back up in power. It literally feels like you let all the way off the gas and then stomp it hard.

In 2nd gear, if I shift early, i get a smooth initial power, then a massive surge. Dave tuned around it, and it is gone now, but the default power application curve did that with my Maggie all the time.

Seriously, if you can duplicate it, take it to your dealership and ask for someone to do a ride-a-long so you can show them what you mean. Then let them resolve it. Don't mess with anything testing it yourself that they may use to void your warranty and make it your problem.

 

[JTDay]

Appreciate the input guys.

 

[JTDay]

Here's the gear whine noise I'm referring to. It might be tough to hear above the wind noise but it's that high-pitched whining noise. It's more clearly pronounced in person. I've got what I think is a drivetrain vibration so I'm getting a tire balance to rule that out for the dealer so maybe I just have a bad axle or something. If we reach a solution, I'll post back.

Not sure this Google link will embed properly but here's the video

https://photos.app.goo.gl/i1GvzcZUw91niQbW8

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