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73-87 Chevy _ GMC Trucks => 4 Wheel Drives => Topic started by: Dirka on October 09, 2014, 07:57:32 PM

Title: 4x4 shifting
Post by: Dirka on October 09, 2014, 07:57:32 PM
Just installed my TH250?NP203 back under my truck today, got everything buttoned up.
I get into truck and run the shifter, and I feel like it only "locks" into 3 different positions..
I'm still in the process of putting the rebuilt engine back in, so can't test which I have, but is there anything I could have done wrong to only have 3 positions??
Title: Re: 4x4 shifting
Post by: Captkaos on October 09, 2014, 08:07:30 PM
TH250?  You mean TH350?  By 3 posistions you me it only moves in 3 slots?  Did it previously have this same trans setup?  If so pull off the linkage and work the trans lever to verify PRNDLL.
Title: Re: 4x4 shifting
Post by: Dirka on October 09, 2014, 08:18:04 PM
Capt, yes 350.. I don't always go back and spell check. Guess high school didn't teach me anything  :o :o
I did check the PRNDLL I get all of those from the tranny.
I'm talking about the transfer case.
Title: Re: 4x4 shifting
Post by: FlatBlack77 on October 09, 2014, 10:46:23 PM
i had a similar problem when i first got my 79. it felt like it only had 3 positions and was really hard to shift.

turned out i had to put so much effort into shifting that it was skipping over 1 and even 2 positions when it would move because i was pushing so hard.

if you understood that lol

take the shifter boot off and see whats goin on. i sprayed some lube on it and havent had a problem since
Title: Re: 4x4 shifting
Post by: Dirka on October 11, 2014, 11:04:16 AM
take the shifter boot off and see whats goin on. i sprayed some lube on it and havent had a problem since

Looks like I will put some lube on it before I put interior back in. Thanks!
Title: Re: 4x4 shifting
Post by: Jason S on October 11, 2014, 12:09:58 PM
You might want to take the shifter off, take it apart and clean all the internal parts.  Cleaning out any mud, old grease and rust will help a lot with shifter operation.
Title: Re: 4x4 shifting
Post by: Dirka on October 31, 2014, 04:57:12 PM
OK another quick question.  I replaced the metal hold down piece that goes around rubber boot and it doesn't have the markings for Hi, Lo, N Lo Lock, Hi Lock.. Of course N is in the middle and I found Low was pushed forward, and HI was pulled back all the way. I haven't locked the hubs, will that give me an extra gear to put in, or will it remain just those three?
Title: Re: 4x4 shifting
Post by: Jason S on November 03, 2014, 10:17:56 AM
There should be 5 positions, regardless of whether your NP203 has a part-time conversion or is still full time.

If your NP203 has a part-time conversion you gain a 2wd-lo and can run hubs in the front. With the part-time conversion, shifter all the way forward (closest to the dash) and moving backward (toward the seat):
Lo-Loc is 4wd Lo
Lo is 2wd Lo
N is still neutral
Hi is 2wd Hi
Hi-Loc is 4wd Hi