"lost" 3rd gear while data logging

[rjacobs]

Was out doing data log runs for ZFG tune revisions.

Probably did 5 or 6 pulls for ZFG logging I guess(3rd and 4th gear). Trying to time out the lag from pushing start and it actually starting to log...frustrating.

Decided to do a few 3rd gear pulls for virtual dyno(cant figure this crazy program out) and was feeling some hesitation during the pull so i loaded up Adam's channels to grab him a datalog of the hesitation.

Started 3rd gear pull and at like 5200rpm the engine just bounced off the limiter. I paddled to 4th and 4th seemed to grab. Put it back in D from M and drove around, 3rd seems to be fine. Ran it through the gears a few times from 1-4 and all seems good.

Im wondering if I just got the trans too hot doing all those pulls repeatedly with really no cool down time.

I definitely caught some odd "TCC slip" and "Trans Output Shaft RPM" logs between the "good" 3rd gear pulls and the 3rd gear pull where I "lost" 3rd at the top of the pull. During the "good" pulls there is basically zero TCC slip and during the one where 3rd went bonkers, there was A TON of TCC slip. Trans Output shaft RPM between the two runs was also different with the bad run having much lower output shaft RPM(obviously due to it slipping so bad).

Maybe Adam will see something in the data that might give him an idea.

Any thoughts from anybody with more knowledge than me?

 

[zdubyadubya]

did you turn traction control off for your runs?

 

[rjacobs]

did you turn traction control off for your runs?

yes

 

[TMac]

It's obvious that the bands/clutches were slipping. Check the trans fluid, it it dark? Does it have a bitter/burned smell? You might want to consider a fluid change if so. You are probably right, just too hot.

 

[rjacobs]

It wasn't like it was slipping though. It was almost like the computer released the clutches to protect things. It was like it completely came out of gear if it was a manual. Didn't feel like classic "slipping" to me.

 

[TMac]

Most vehicles have various strategies to limit torque to protect components. However, I'm don't believe anyone would program the trans to drop into a "neutral" mode just to bounce off the rev limiter when the vehicle could just cut fuel, open waste gates, or pull timing to achieve the same result.

 

[rjacobs]

Most vehicles have various strategies to limit torque to protect components. However, I'm don't believe anyone would program the trans to drop into a "neutral" mode just to bounce off the rev limiter when the vehicle could just cut fuel, open waste gates, or pull timing to achieve the same result.

Yea I don't know. Doesnt seem to be any worse for the wear.

I sent the log file to Adam so maybe he will see something.

 

[Blown F-150]

I would give Adam some time to look at it. It’s sounds like a odd scenario to hit a clip, but you could have hit some limit that he has in place for a reason or a limit he didn’t know have to be lifted/adjusted just yet.


Sent from my iPhone using Tapatalk

 

[boiler662]

It's obvious that the bands/clutches were slipping. Check the trans fluid, it it dark? Does it have a bitter/burned smell? You might want to consider a fluid change if so. You are probably right, just too hot.

Good luck with all that

 

[UNBROKEN]

Good luck with all that

There’s a dipstick hidden in there. It’s not that bad to access.

 

[boiler662]

There’s a dipstick hidden in there. It’s not that bad to access.

Your right and its way more of a PITA than a dip stick under the hood, I do not see many people doing that fluid check at home while the vehicle is running......

 

[rjacobs]

Adam said it didn't come out of gear or slip. It downshifted to 1st mid pull, then went to 4th I guess when I paddled it. I never saw 1st on the dash.

He wants some datalog of a few 0-60 pulls shifting through the gears.