700r4/NP208 wont shift into 4lo or out of neutral

Lurked a little bit, first post here though. Have a project 85 K20 with a 700r4/np208/auto lockers(I know, probably the worst combo in the history of recorded squares) that refuses to shift into 4Lo. The shifter is all outta wack right now and my dad (who's owned 5 squares himself) says its an adjustment issue with the shifter, but that doesn't explain why the T-case won't shift into 4Lo. I've been running it in 4Hi (rear brakes aren't adjusted out right so the tires just spin in 2Hi, it shifts fine inbetween 2Hi and 4Hi) and I'll shift the transmission into neutral, then the T-Case into neutral, then when I attempt to shift into 4Lo it just grinds and won't go in, and if I attempt to shift back into 4Hi it grinds aswell. Only way to put it in 4Lo is to shift the truck off and shift it (same w/4Hi). I want to reuse this case when I swap in a 6.2/4l80e this winter because A) I like the shift pattern and B) one less thing to buy. So, anyone have any idea why this thing won't shift in 4Lo?

not knowing the intricates of the NP208, but my thought with old school vehicles you don't shift the transfer case while moving. That's the only reason to me why ANY old school transfercase would grind. I'm sure someone will correct me if I'm wrong.

Hell I was afraid to do it in my 99 durango while on the interstate cuz of this thought.

your auto should want to be in neutral, then and then

Sounds like you're trying it right by putting trans in neutral.
Does your truck idle high? Maybe it's got too much kinetic energy spinning things from idling high?

squaredeal91 said:

Sounds like you're trying it right by putting trans in neutral.
Does your truck idle high? Maybe it's got too much kinetic energy spinning things from idling high?

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lol again....thought the truck had to not be moving. If not disregard lol.

Camar068 said:

lol again....thought the truck had to not be moving. If not disregard lol.

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you are correct camar. the truck cannot move because the 4lo range requires the case components not to be moving, if the truck is rolling at all its going to grind

Then in an automatic, you need to be in neutral or turned off , because .. well im not sure, i think its the same situation because of the torque converter but Im less sure, i just know the shifter is engaging a component and thae stuff cant be spinning it wiull just grind and make harshness as it fails to engage fully


So idle high is a good question for OP, and s he in neutral with the truck absolutely stopped. Because bad rear brakes... well.. if he was in neutral they shouldnt be moving.

Yes 4 lo should be in neutral, not moving. 4 hi can be moving and in gear under throttle. The transfer case has to not be spinning to go to 4 lo.

208, 4lo should be all the way down past 4 hi. Shift into 4 hi then trans in neutral then 4 lo. Linkage adjustment is important also.

I've hit 4 hi under power on mud snow and ice, with a 208 even.

Alright, Lotta responses so I'm just gonna cover all quick:
1- Transmission was in neutral when I attempted this, and stopped aswell.
2- Idle solenoid is shot and so is the choke solenoid so I've been having to keep it running via the gas pedal, so technically high idle.
3- was two footing it and had the brake held on aswell (incase the thing slipped into drive) so I was not moving.
Yall are probably right with the whole too much kinetic energy and spinning thing. I won't mess with it until I get those solenoids changed and the shifter adjusted. Hope the parking sprag ain't shot and that might be a possibility because if I don't hold up the shifter it'll slip into reverse.
Thanks for the help yall.

PrairieDrifter said:

Yes 4 lo should be in neutral, not moving. 4 hi can be moving and in gear under throttle. The transfer case has to not be spinning to go to 4 lo.

208, 4lo should be all the way down past 4 hi. Shift into 4 hi then trans in neutral then 4 lo. Linkage adjustment is important also.

I've hit 4 hi under power on mud snow and ice, with a 208 even.

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you do have to pass neutral to get to 4lo, which is down to the right of the others. I know on mine the actual shiftert itself was giving me some issues trying to put it in neutral i think i fixed the issue but slightly movign the truck just enough to maybe unbind something

hazardous said:

Alright, Lotta responses so I'm just gonna cover all quick:
1- Transmission was in neutral when I attempted this, and stopped aswell.
2- Idle solenoid is shot and so is the choke solenoid so I've been having to keep it running via the gas pedal, so technically high idle.
3- was two footing it and had the brake held on aswell (incase the thing slipped into drive) so I was not moving.
Yall are probably right with the whole too much kinetic energy and spinning thing. I won't mess with it until I get those solenoids changed and the shifter adjusted. Hope the parking sprag ain't shot and that might be a possibility because if I don't hold up the shifter it'll slip into reverse.
Thanks for the help yall.

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it what!? I wonder if your column needs to be adjusted to your manual valve on trans? That doesnt seem right\----------------------------------------------

When you do it engine off, trans in neutral, I know mine will grind if I have trans in neutral, t case in neutral for a while, then try to shift to 4 lo. If I'm quick, there's no real movement, but if it idles a bit, some of the drag gets the trans output spinning, it seems like. I have a TH400 so it may be different than your 700, but seems similar. But also could easily be the linkage needing adjustment, especially if that's the diagnosis from the old man that's seen it in person. If you have the opportunity, you might also try it while rolling VERY slowly (no "Miles per hour", just "inches per minute"), and shifting past N on the quicker side of slow, without blipping the throttle as you go.