Problem with NP208 TC

[chevy80]

Hello guys it is my first time to this forum, I am facing an issue with my TC it is NP208. I noted the front drive shaft is spinning slowly even when TC is on 2H and the hub lock on free, i can turn the front shaft with my hand. I’ve checked the linkage under the cap and makes sure it is on 2H, I noted that when I hit the gas while the truck on a slope I can see the front shaft is spinning and it happen the same while turning the truck. Any idea what is the problem is.

 

[K85 Octane]

1) is the front shaft spinning the same as the rear?
2) only when the truck is moving? Or somehow while it's not moving?
3) pull your front hubs off, to be completely sure
4) also, pull the linkage off the t-case and manually push the lever all the way rearward, this is the 2H position. This bypasses any linkage/shifter problems.

 

[chevy80]

1) is the front shaft spinning the same as the rear?
2) only when the truck is moving? Or somehow while it's not moving?
3) pull your front hubs off, to be completely sure
4) also, pull the linkage off the t-case and manually push the lever all the way rearward, this is the 2H position. This bypasses any linkage/shifter problems.

1) no the front shaft spinning slower than the rear
2) sometimes when i hit the gas while the truck is stand i feel the front axle spinning and the truck being heavy
3) i did pulled the front hub off but it is the same
4) when i start notes the problem the linkage to the T case was removed.

where should i look to solve the problem

 

[Stomis]

The front shaft spinning isnt uncommon. The thing will float around a little from fluid movement in the case even when the front axle is unlocked and its in 2 wheel.

Is this actually causing a problem or is it just something you noticed you felt was wrong?

 

[chevy80]

The front shaft spinning isnt uncommon. The thing will float around a little from fluid movement in the case even when the front axle is unlocked and its in 2 wheel.

Is this actually causing a problem or is it just something you noticed you felt was wrong?

when it happen i feel the truck movement is heavy,

 

[n4xplay]

Well if you can turn every thing by hand then what you are seeing is a slite drag in the system it can either be in the transfer case or I slight bind in the front end ... With the hubs free drive it and have someone see if they can tell if your axle shafts are spinning in the knuckles . If they are not then it is coming from the TC and more than Lilly not something to worie about unless it's making noise

 

[n4xplay]

But if your shafts are turning then its a different story all together and I would recommend going threw each hub to find out what's wrong ... You mentioned it felt heavy have you checked your front tires for bearing play yet ?

 

[chevy80]

Well if you can turn every thing by hand then what you are seeing is a slite drag in the system it can either be in the transfer case or I slight bind in the front end ... With the hubs free drive it and have someone see if they can tell if your axle shafts are spinning in the knuckles . If they are not then it is coming from the TC and more than Lilly not something to worie about unless it's making noise

I did ask one of my friend to check the axle shaft while hubs are free they do not spin in the knuckles. What else to check

 

[K85 Octane]

at least one axle shaft should be spinning if the driveshaft is turning, if neither are spinning, there is a problem whether the hubs are locked or not.

Have you had this truck in 4wd? How did it do? Almost sounds like you are missing something in the front carrier, allowing the axle to "not move" and the driveshaft to float without tension.

not sure, just throwing it out there

 

[Fordum]

The gears in the transfer case that drive the front shaft are very close together. So, if the front hubs are disengaged, there is almost no load on the front drive shaft.

With the oil between the gears, its not uncommon for the front shaft to be driven by friction from the oil.
Also, I have seen the grease in the front hubs drive the axles, which drives the shaft.

All this is perfectly normal and is not a problem.

Its almost impossible for this to cause any problems or noticeable changes in your driving.
Because either the transfer case could malfunction and engage your driveshaft without your knowing, or a hub could engage, and you would never feel it.

You can put the transfer case in 4wd and not turn the hubs, and it will not affect the driving if the hubs are working.

You might pick up a vibration with the front shaft spinning if its worn or not balanced, but no heavy feeling.

Also, you could engage the hubs and not put it in 4wd, and have the same effect.

The only way for that to affect your feeling, is to engage both hubs and transfer case on hard pavement or packed ground.

Then you would really notice it, and it would not be good for your drivetrain.

The only other possibility would be if you had a locker or posi unit in the front end, and both hubs were engaged.
Then you would notice it when turning.

Just for fun, you could notice which way the shaft turns, tie a piece of heavy twine or string around it and wind it a few times in that direction so it clamps the shaft tight.
Then tie the twine off to the frame.

If anything is engaging hard enough to affect your driving, its going to break that twine.

If not, then the shaft will no longer turn. At least, until you forget and put it in 4wd........

Be sure to remove it before doing that.
And I suggested twine, instead of heavy rope or strap just in case. So that it would break if you forgot or something was engaging.

 

[K85 Octane]

haha, barber pole affect.

x2 what J said

My shaft doesn't turn, but there's a locker in the front and it would take a lot to freely spin the axle shafts.

 

[chevy80]

i disassembled the TC from the transmission, on the floor i removed the TC cover
to see if i there is anything unusual (do not know what is usual..) anyway, when i spin the main shaft by hand i can see the chain and front shaft are spinning. i asked my friend to hold the front shaft, while i spinning the main shaft i did not note any problem with main shaft spinning....!!!

 

[Blue85]

The chain should only turn when 4HI or 4LO is selected. If someone can stop it by hand, then everything is fine. Otherwise there is something wrong with the mode fork (i.e. you select 2WD, but the case is in 4WD). You might try moving the selector slightly further than it "should be" for that mode, just to help full engage/disengage if the fork pads are worn. The first thing to check is always for proper adjustment of the shift linkage.

It is common for the the teflon pads to wear off the mode and range forks (just a matter of time, really). Shifting then becomes more erratic and eventually the steel forks themselves will wear away until you can hardly select the mode/range you want anymore.