2001 LT Blazer lunges forward when started
 

So, my girlfriend says her truck lunges forward sometimes when she starts it. It has auto-matic transmission.

Last night I took her truck for a drive :icon_playing: to play with the 4 wheel drive just to make sure it was ready for the winter.

Well ... it goes into 4Hi nicely. Drive it for a little bit. But it won't come out :icon_confused:. I do the forwards and backwards tricks you normally do for blazers ...no go. (either 4LO or 2HI) My brother shows up to the house so he and I go out :icon_rally:. After about 15 more minutes of that non-sense. We park the truck. I go running to my computer to go to my favorite blazer forum:icon_user:!! I read all 245 threads and replys. I leave up about 10 of them so I could get to them this morning if I need to re-look at them for reference.

:icon_arrow:This morning I get up, kinda mind bungled from reading all the forums last night, go out to put truck in garage to do all neat things I learned to do on here. I go to start the truck and :eek: the truck lunges forward!! Keeping my calmness... I gracefully lean over and push the 2HI button. And as if there was no problem, went back into 2HI. :icon_special:


So my question is, what could cause this :icon_question:

*Moving to Engine & Transmission* - The forum help & suggestions center is for forum software related questions, not technical help with your vehicle.

Here is a thread that came up.
Slight lurch upon startup...

I know I posted a resolution, but it must have been lost in one of the server/software changes way back when. I can't remember exactly what it is, but I know there was another thread that discussed it. I don't have the time right now to dig further into it though. Something about fluid staying back up in the clutch packs holding them in the applied position which then released once you started the engine back up. Once I started allowing the engine to run a bit after I put it in park, I really didn't notice the problem again.

As far as the transfer case going all wonky, it's kind of a common occurrence. Check the connections at the TCCM, switch, and encoder motor for corrosion and make sure that they are clean and tight. After that, we really need to know what you have for a transfer case to help further.

Yea. Mine does the lunge/jerk. I read the solution Swartlkk posted a while back and he summed it pretty good. Just fluid under presser until its released. Almost feels like a bad shift. Just wait till COLD weather when it feels like its going to spin the whole truck on its roof.

Good deal!! Thanks guys. I love this forum. Have been on here a lot!! I thought I finally ran into a problem that no one had talked about!! Sorry I put it into the wrong catagory, still trying to figure out how to get things where I want it.

Will try to fair the weather till it warms up a little then try the fluid and filter change. If not, will check into the TCC in the other forum. But will get on right away checking the other items. Thanks for the short cut!!