Automatic transmission jumping out of gear?

Thanks for the reassurance that it's likely a fluid issue.

The majority of this truck's miles are just loping along at 65-70 MPH, but when I have a lot of ground to cover like this past week's trip, I tend to average 85+. Couple that with the added weight of being loaded up, plus the long hills out here and you're looking at lots of skinny pedal.

The aforementioned 35s don't help, but 5.29 gears mitigate their effect.

 

sounds like low fluid level. also the ecu was not programmed for the 5.29 gears and larger tires

 

The tune was done after the tires and gears, I assume he took that into account.

 

@Mooseditty17, sounds like the issue you've had with 5.29's.

 

Not trying to smart at all, but do you know it actually has the right amount of transmission fluid? Did you check it yourself?

 

Drivetrain edits in the tune only adjust distance to empty values. Nothing more.

Does it seem like this?
Link to post
Link to video

 

I don't know, haven't checked yet. This just started happening and I haven't had enough downtime to get under the truck.

 

You need to bring this to Mathew Wilson's attention. I bitched about this years ago. Likely high line pressure, but that's not adjustable on 3rd gen, just 2nd gen. If you set your SP to 108+ for 3-4 US @ 100% accelerator and it'll bang too. Adjustments to torque shift maps soften it some, but mostly just make it shift earlier. There's a definite threshold from 105-108 somewhere. 1rst and 2nd gear can rev to 6800 rpm with zero issues. 3rd you can only get 6500 TOPS! I've been chasing this anomaly for years. I've never done a 4-5 WOT shift yet. 115 is enough for me on 35" mud terrains.

 

Yeah, that's definitely similar to what I'm experiencing.

I've had this tune for at least 5K miles though - strange that it would just start doing this now.

 

This was back when I was still on 3.90 + 33s. Had my Upshift set above 115. Thought the fuckin rear end dropped out. This was early enough in my tuning career that literally shift points and tip in was all that was adjusted...

https://photos.app.goo.gl/c8tnfygKGGRh6E479

It's definitely not limited to 5.29s

 

This was a different tuner, local to SoCal. LOL and yes, 115 MPH is above my comfort zone on 35" MTs.

 

I'm not saying Mat tuned you. Anyone that tunes you with those parameters will cause this to happen. IMO it's a glitch. I believe Mat Wilson, the creator of VFTuning can help address this though.

 

That's giving me flashbacks...

 

I've tried tuning it out... Unfortunately that means I've had to experience this several times. Feel so bad for the truck

What gets me is 1:2 and 2:3 don't have the issue... Only 3:4

 

I had a 2019 that would hit fuel cutoff when i was in S mode

 

Yeah it'll do that if you wait too long to give it an "upshift" input. As mentioned though, that's not what's happening here. I push the stick forward well before the intended shift point (or, I did - not doing that anymore as it appears the tranny doesn't like it).

 

that's scary

 

wow...

 

So, I got a trans flush at the dealer and, yep, it's still doing the insanely violent 3-4 upshift on high RPM and lots of throttle. This is happening in D now, haven't tried upshifting in S-mode like an auto stick since the first day this happened.

Doesn't happen in any other gear or situation. Only when on the gas hard in 3rd long enough to make it shift into 4th.

The fact that it just started happening recently after thousands of miles on my Sibi tune makes me question that being the cause.

Could this be a solenoid issue?

 

Your torque converter could be shitting out... Have you tried another tune, flashing back to stock, or anything of the sort to eliminate that variable?