I asked this in the drag racing section but I think it may get better viewing here so here goes.

If you launch in 4HI and then hit the 2WD button does your trans really shift back to 2WD or is this impossible for the trans to do?
I just want to know how much poer I'm leaving on the table if your trans is really in 4WD when you think its in 2WD.
Here is my other post. Thanks everyone.

https://www.performancetrucks.net/fo...d.php?t=352524

 

It wont shift back into 2wd if you have any kind of decent power. When I sprayed my truck on the stock motor it wouldnt shift out of 4wd under WOT. Doesnt take that much more power leave it 4wd well actually you have no choice it will dtay in 4wd under WOT with the turbo on it.

 

Wanna bad *** launch, put her in 4low, and hammer it. She will beat any thing to 3rd gear. But your powertrain might not be up to the task too many times.

 

I've read some post that it won't got back to 2WD. I launch 4WD always at the track and then hit the 2wd button after the 1-2 shift. I get a 2WD light. Sometimes I forget to hit the 2wd button and I can tell when I don't. I drop a couple tenths and I get a vibration at about 90. Don't know what is happening but something is.

 

will leaving in 4hi on the street damage any components.

 

WOuldnt recommend doing alot of turning on dry pavement, you will befine going in a straight line.

 

So what I'm hearing is it won't shift back into 2WD but it is diverting the power to the rear wheels mainly after the shift back to 2WD??
If this is true its good enough for me, if not I have to learn to launch in 2WD to take advantage of all the power I have now.
I wonder if any mechanics will chime in on this part of the subject.
Even if your 2WD light is lit after launching in 4HI, is your transfer case still getting power diverted to it?

 

NO if you have a decent amount of power it WONT shift to 2wd(send power only to the rear wheels) until after you let off the gas. Mine and alot of others guys wont shift out of 4wd like that and it isnt as parasitic of a loss as you might think.

 

an understanding of the way the TCase works in order first...the TCase is ALWAYS on, the front shaft is always engaged...when you go "4WD" a plunger engages the front pinion. When it's in "auto" the pinion will engage when the pcm interprets wheel slip/spin...those good ole vss'. This is a good reason why you don't use auto with any good power...I already broke that plunger once.

In 4WD hi if you produce a good bit of power that plunger might come back to let it go back to 2wd...however...the constant force of "application" won't let it until you let off of it. Light might go to 2wd, but I seriously doubt that if your always WOT.

 

The front shaft is not always turning. It is engaged only for 4wd use. When in 2wd the front disconnect and the front output of the t-case are both disengaged. When in 4-auto the front diconnect is engaged and the t-case is not.