NP241C issues, this is weird, help !!!

[mtnmankev]

So, I got the 27 spline input shaft installed in the 241C, fit perfectly and all bearings and shafts in the donor transfer case were good.
Reassembled the unit and installed in the truck.
Now, if I try to put it in 2 high, it will move without turning the front driveshaft, but it grinds and sounds like it's in two gears at once.
4 high seems to work normally and quiet.
AND, the selector will NOT move to neutral or 4 low.

Is there a chance it's a full time 4x4 241?
Here are the numbers on the tag on the back.
NP241C
Assy# 15624672
Ser # 927882
Mfg 1988

ALSO, here is the diagram (from an online parts source) that I used for the assembly.
Any ideas where I might have gone wrong ?

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[RoryH19]

I have a 241c in my k5. It's behind a 4L65E. I had to adjust the shift linkage a bit since it started with a 208 and 700r4.

When you rebuilt the t-case were you able to turn the selector for all positions when out of the truck?

Did you also test what ends turn when in different positions?

 

[mtnmankev]

On the bench the selector moved between 2H and 4H but no farther, I was thinking it was because I didn't have enough oomph or leverage on it.
The linkage from the shifter was adjusted a couple times in hopes of curing it.
When in 2H only the rear driveshaft turns but it makes the grinding noise.
In 4H the front driveshaft turns and all is quiet from inside the transfer case.

 

[mtnmankev]

I think my helper had a semi lucid moment just now, he asked if there was a chance we didn't put the shift thingy (inside the T case) in a certain needed position before we assembled the unit.
And it doesn't help that there is ZERO information that I could find online about specific assembly procedures.
I am the kind of person who needs very specific exact details about stuff.
And 99.999999999% of any manual or repair info I have ever seen in my life lacks the required specificity.

If that was the case with the shift thingy, it should be a simple fix, provided I can find out EXACTLY which way it needs to be in the case upon assembly.
Just a pain in the rear to remove the case, disassemble, make a change, reassemble and install.

 

[mtnmankev]

Plus there's a chance I may have installed the synchronizer sleeve gear in backwards, which would throw off the mode fork operation.

 

[mtnmankev]

The gear is now on correctly.
It's on the bench open still, and I can shift it through the range from 4L to 2H only, it will not shift back the other way, something is keeping the fork/gears from moving.
Any ideas ??

 

[RoryH19]

I rebuilt mine, at least released everything before installing. I used a you tube video to check I didn't forget anything.
I'll find the link.

 

[mtnmankev]

It's obvious the rod that the forks are on needs to slide back and forth a little inside the case so the gear can change modes, but something is preventing it from doing so going from 2H to 4L.
If I raise the fork and gear, and manually move the shifter lever to 4L, then reseat the gears, it will move from 4L to 2H only.
This is driving me nuts and I need the truck done before the expected winter storm tomorrow.

 

[RoryH19]

Couldn't find the video I used but maybe this will help.

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[mtnmankev]

This makes absolutely no sense to me, it's NOT in ANY video or manual, but the secret is to not install the parts one at a time.
It's necessary to have the mainshaft, synchro sleeve gear, and mode fork/rod assembly all together, THEN insert into the case at once as a clump, and it shifts through the ranges fine.
It totally defies any logic, but as long as it works I'm not going to argue.

 

[mtnmankev]

All assembled, filled with ATF, and moved the truck under power in the driveway, the T case is QUIET, but then again the worn out 208 it replaced made more than its share of noise.
All modes function as supposed to.
Now that it's fixed, the mud will dry out and we won't get any more snow or rain.

 

[idahovette]

All assembled, filled with ATF, and moved the truck under power in the driveway, the T case is QUIET, but then again the worn out 208 it replaced made more than its share of noise.
All modes function as supposed to.
Now that it's fixed, the mud will dry out and we won't get any more snow or rain.

Insurance!