Is this from torque converter lockup?

I drive my 3rd Gen in S4 and S5. I stay in S4 until I get up to highway speeds, then I shift to S5, but S5 appears to shift twice.

It's most noticeable in the morning before the trans has warmed up to operating temp. When it shifts into 5th I see around 2k rpm, then after trans oil reaches temp it appears to shift again and I'll be at ~1800rpm. It's not 6th gear, because I'm not in S6.

I'll also notice this on hills. In 5th it appears to downshift slightly. It's not 4th because if I shift into S4 it will downshift once again. I also notice when it's in this "in between" stage my trans temps climb.

My assumption is the converter is not locked up in that "in between" stage, and what I'm feeling is from the converter slipping and giving that feeling of a different ratio (which also explains temp rise). Is this the case?

 

I have the same question and drive the same way. Is there a specific reading I can get from my scangauge iii that tells me whether TC is locked or not?

 

Upon further research I was correct. 1-3rd the TC never fully locks, 4th is 1:1 and stays locked, 5th and 6th will unlock as needed.

Now what I want to know is can I force lock in 5th? I would prefer it never slip in 5th, if it needs power then downshift.

 

Inb4 manual transmission bro’s

 

You can get a custom tune that will give you what you want.

Fwiw, I drive the same. 4th for everywhere around town, 5th and 6th for away.

 

The transmission will lock or unlock in any gear. When I tow I watch my trans temps like a hawk and I've seen it lock/unlock and the TC ramp up temps in 4th many times.

 

Really?! That would be awesome. I'm geared with 5.29s now, and I'd like to tow my 1800lb trailer in 5th vs 4th. My hope is forcing the TC to stay locked would prevent climbing temps.

Strange, I've never had 4th unlock while towing.

 

I see it pretty regularly. Do you monitor your TC temp or just the pan?

 

Both. 1600 mile trip a few weeks ago and I never saw TC temps rise higher than pan temps except in 3rd when climbing a 6% grade. I'll have to figure out how to display lockup status and watch it.

Also, those lockup schedule graphs you quoted arent making sense to me lol

 

They don't make a lot of sense to me either, but I found them quoted in another thread and thought they could be useful for someone.

Lots of rolling hills around where I live and that's where I see the TC locking/unlocking the most often in those varying conditions around a fairly constant speed.