My NP208 will not stay in 4hi

[blazing816]

I have a TH350 with a NP208 and I have had a problem with putting my truck in 4WD (and with the white fluffy stuff coming need to sort it out). So here is what happend I can put the truck in 4HI just fine but as i go down the road the lever wiggles forward and eventually it comes out of 4hi. What would cause that?? A transmission place (that is no longer in business...so dont believe them anymore) told me it was casue I had the wrong crossmeber and the lever was at the wrong position. Any thoughts??

The other problem is I can put my truck in netural/netrual and then shift into 4lo, but when I am done, I go to put it back in netural/netrual and everytime I go to push the 4wd lever to netural it grinds like it has not stoped spinning...I have to shut my truck off to get it out of 4lo. Not as important cause I do not really use it but starting to think I just need a new transfer case. Any thoughts??

*edit* Also I the truck was built with a 700r4 and someone, before me, converted it to a TH350...do not know if that matters.*edit*

[mikek20]

have you lifted the truck (body or suspension) and have you shimmed the cross member or dropped it at all?
Theres a few things that have come to my mind as you have described the problem. some simple. some complex

[Blazin]

It could be as simple as the shift rod for the transfer case is in need of adjustment.
 
As far as shifting it into low it should shift in and out of low range as long you are not moving.

[blazing816]

No lift that I know of....but I swear this has had 100 different people working on it before me. But what I was told from a trans place it was the crossmember for the 700r4 not the TH350.

How to I adjust the lever properlly or is it just trail and error?

And I am not moving when I try to go out of 4lo I have the truck in neutral and foot on brake and it still grinds like crazy....and I have to turn truck off to get it out of 4lo.

[pholliday1]

the proper way to adjust 4wd lever is to disconect the "rod" from the t case at the top then try to shift transfer case using the part stiil attached to the t case from underneath the truck and "feel" if the t case is actually going from 4 hi n and then 4lo if the tcase shifts normal then your next step is to adjust the threaded rod that connects the tcase to the shifter. np 208's notorious for having worn shift forks, also your truck having a th350 and a 208 tcase suggests that is the trans was changed from a 700r4 to th350, which is no big deal is just changes the location of the t case therefore leaving the shifting arm for the tcase to b adjusted. also the 4lo issue  are you  putting vehicle in neutral then letting of brake so there is no axle wind up before you go to 4hi?

[blazing816]

'pholliday1' from what I remeber have to try it again tonight or tomorrow but usally I put truck in neutral and have the brake engaged. Are you saying I should have my foot off the brake after shifting into neutral??? what if I am not on a flat surface?? Thanks again for the help....I will deffintly unhook the rod and try shifting it and see if it will go in the gear to see if the yoke is okay.

And that makes alot of since that the tcase move a little with the change and has to be adjusted...becuase the trans was out of whack when I got it also (shift linkage needing adjusting). I asked them to look at tcase too and they told it was working just a little hard to get in gear because it was "mounted" wrong. I am starting to think they just didnt want to do the work or something since they are no longer in business.

[Blazin]

I put the 208 in my Blazer into 4 Lo all the time in drive. Just stop, hold the brake, shift it, then let off the brake I have never put it in nuetral, or park. Sometimes as its shifting into Lo I have to take my foot off the brake, and actually let it roll a few inches as it goes in.
I don't use low very often in my 86 K20. When I do I push the clutch in, as I come to a complete stop, or pretty darn close. 1, or 2 MPH, and shift it into Lo, trans stays in gear.

[pholliday1]

With the 4lo issue,(going from 4lo to 4hi or 2wd) i put truck in neutral let truck roll a little if need be..to make sure there is no built up drivetrain binding then slide 4wd lever all in one motion. I am frequently in 4lo off road and generally i make sure  im on fairly flat surface when i shift out of 4lo. Going into 4lo i put trans in neutral then go from 4hi to 4lo and it always works good no problems. Hope this helps?