NP208 rebuild issue/problem

[jabara572]

Hey guys, I just fully rebuilt a low miles NP208C transfer case.

Took photos on disassembly, used the manual step by step, verified all parts are in place, so I am really struggling to understand if I did something wrong.

The issue is: case will shift beautifully through all ranges, everything works as it should, no grinding or binding, very easy to spin the mainshaft and front output..WITH the tail housing OFF.

Problem is, when I put the tail housing on, and tighten the bolts, all of a sudden 4Low becomes extremely hard to turn the shafts. 2Hi, 4Hi, and Neutral all spin freely and easily, but 4Low just seems like there is monster preload on a bearing (if you ever over tightened a front hub bearing and tried to spin it, thats what it feels like), no grinding or other noises, just hard to spin. Its not impossible, I can grab the front output shaft and turn it by hand, but its probably 10 times harder to spin than without the housing on.

If i back off of the tail housing bolts just 1 or 2 turns, it is again super easy to spin in 4Low. I just cant for the life of my figure out why the tailshaft housing is affecting anything, and especially why it ONLY affects 4Low. Is it supposed to be that hard to spin when new? It just seems odd that a couple thousands of play results in an easy to spin transfer case or one thats much harder.

Any thoughts?

Thanks

 

[jabara572]

Well... in case anyone searches for this in the future....

Could not figure this out for the longest time. A real head scratcher... but i was right that the main shaft wasnt going forward enough in the case, and pressure from the tailshaft was locking everything up. The only thing I can think of is that the needle/roller bearings inside the input shaft (where the tip of the mainshaft fits) was not driven in far enough (no depth is listed in the manual IIRC).

I tapped the rear of the mainshaft with a mallet and felt it move lower, instantly problem was solved. So that's all I can think of.... either way, a few smacks with a BFG solved it, case spins easily by hand in all ranges/gears, so when you put in the needle bearings for the mainshaft make sure they go deep enough into the input gear

 

[Cuba]

sorry no one had any input. But grateful you did provide an answer!! Thanks for updating and great job figuring it out!

 

[HotRodPC]

No doubt Jabara. Sorry noone responded to this. USUALLY, even when someone doesn't know something, we know who does. Though I'll admit, I don't know that we have any Transfer Case experts. We do have a few that know a little bit but not an expert. That might be why noone responded. Might have had a forum outage too because it's rare threads don't get responded to here.

Thanks a bunch for the update. I'm sure it'll help someone in the future. Welcome to GMSB !!!

 

[Honky Kong jr]

How did I miss this??? That's awesome you got it going properly.

 

[HotRodPC]

I don't know. Everyone missed it, and he has it in the right category. So I dunno? Not the norm around here.

 

[Honky Kong jr]

I don't know. Everyone missed it, and he has it in the right category. So I dunno? Not the norm around here.

I agree especially since all the crap I did to my TC. With switching the input to 32spline gotta tear them down pretty far for that to happen.

 

[jabara572]

I agree especially since all the crap I did to my TC. With switching the input to 32spline gotta tear them down pretty far for that to happen.

Lol I dont know either... i posted it in the right spot and no one replied I was like O..K...... i thought at least someone would have a thought haha.

No worries, figured id post up the solution in case anyone runs across it.

Thanks guys

 

[Gussie]

Hello, I'm ru ni g into same issue during my rebuild. Currently pilot bearing is flush and when I put n shaft w thrust bearing the end of shaft doesn't make contact with input gear. Was a spec ever found? Or idea on how far to drive the bearing in?