Another np203 Mysterious Popping Noise

[blazink10]

86 k10 350th Np203
Recently a buddy and I tore down the front end and replaced axle u joints, all new ball joints, repacked bearings, and installed a new lockout hub on the passenger side. Trucks been driving great except I’m getting a popping noise from the passenger front when Turning on pavement it doesn’t seem to be felt though the wheel it sounds like the bad u joints before but it’s brand new so I’m clueless. Truck has lockouts and unconverted Np203 I run it in 4hi with hubs locked as I heard it’s harder on the ole 203 to run in hi loc hubs unlocked. Any suggestions would be great front end has been greased and is in good shape sorry for the long winded explanation I’m a bit new round here.

 

[blazink10]

Should be added it mostly occurs when turning left and going forward not in reverse.

 

[ali_c20]

Does the popping noise appear in 4 hi loc with hubs unlocked too? Do you have a locking differential in the front axle?

 

[Octane]

Np 203 is a fulltime case.Doesn't require locking hubs.Also,as far as I know the 203 was discontinued in 1980.Did you just modify the drivetrain?

 

[ali_c20]

It must have the fixed drive flange or locking hubs locked for 4hi. It would not move if you put it in 4hi and unlock the hubs cause all the power would go to the least resistant axle. You need manual hubs for the part time conversion kit.

 

[75gmck25]

As already mentioned, first figure out what you have. Unconverted NP203 and lock/unlock hubs don’t work.

I had similar noises with my NP203 and it turned out to be one of the the u-joints in the double Cardan joint in the front driveshaft. I replaced them all with permanently lubricated u-joints. Also lube the slip joint in the driveshaft.

 

[blazink10]

Does the popping noise appear in 4 hi loc with hubs unlocked too? Do you have a locking differential in the front axle?

 

[blazink10]

No I believe it is an open diff I just drove it for the first time with 4 hi loc and hubs unlocked and absolutely zero pops or scary noises so I'm guessing its related to running in 4hi hubs locked?????

 

[blazink10]

As already mentioned, first figure out what you have. Unconverted NP203 and lock/unlock hubs don’t work.

I had similar noises with my NP203 and it turned out to be one of the the u-joints in the double Cardan joint in the front driveshaft. I replaced them all with permanently lubricated u-joints. Also lube the slip joint in the driveshaft.

 

[blazink10]

I lubed the slip joint previously its unconverted it won t go anywhere in 4 hi hubs unlocked but today I drove it 4 hi loc hubs unlocked and no bad noises so still a bit confused why they never put the kit in?

 

[Octane]

The 1986 trucks had a np205 or maybe the np208.Which require the lockable hubs.

 

[dvdswan]

How tight are the wheel bearings? How are the ball joints?

I understand you stated in the original post "86 k10 350th Np203",

So before everyone goes ballistic and just not wanting to help. Please re-affirm the truck has the NP203 full-time t/case and not the NP208 that it would have come with. The 203 is huge heavy iron case and the 208 is aluminum.

 

[Octane]

My truck has the np203.It is fulltime 4wd.It has hi and hi loc low and low loc.If yours doesnt have the conversion kit then why do you need lockable hubs?

 

[blazink10]

How tight are the wheel bearings? How are the ball joints?

I understand you stated in the original post "86 k10 350th Np203",

So before everyone goes ballistic and just not wanting to help. Please re-affirm the truck has the NP203 full-time t/case and not the NP208 that it would have come with. The 203 is huge heavy iron case and the 208 is aluminum.

 

[blazink10]

I replaced all ball joints and repacked ratings the front end is now in great shape other than that odd noise when running 4i locked hubs not to be co fused with 4 hi loc it is a 203 with manual hubs the truck has been pieces together by previous owners.