Another np203 Mysterious Popping Noise

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

blazink10

Junior Member
Joined
Jul 23, 2021
Posts
11
Reaction score
0
Location
Ohio
First Name
Rylan
Truck Year
1986
Truck Model
K10
Engine Size
305
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

Junior Member
Joined
Jul 23, 2021
Posts
11
Reaction score
0
Location
Ohio
First Name
Rylan
Truck Year
1986
Truck Model
K10
Engine Size
305
I believe previous owner did it to have cheap semi 2wd but I’m not one totally sure.
 

blazink10

Junior Member
Joined
Jul 23, 2021
Posts
11
Reaction score
0
Location
Ohio
First Name
Rylan
Truck Year
1986
Truck Model
K10
Engine Size
305
I understand the 203 has a differential to eliminate binding since there are new u joints and the front end has been serviced including wheel bearings coils it be that the differential just can only do so much it’s only a slight noise but I’m not sure what else it could be or is that the symptom of a bad lockout? I replaced one lockout cap on that side the other crumbled when I took it apart.
 

Turbo4whl

Supporting Member
Supporting Member
Joined
Oct 30, 2019
Posts
3,126
Reaction score
7,255
Location
Downingtown, PA
First Name
Wayne
Truck Year
1974
Truck Model
Jimmy
Engine Size
350
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.

As previously stated, you can not drive a 203 with your hubs locked on a hard drive surface. When you make a turn the front axle always travels further than the rear axle. With the differential locked and you turn the the truck, axle shafts will twist inside the housing until something gives.

You could be trashing one of the new front locking hubs.

More likely, you are forcing the already stretched front drive chain to jump a cog in the transfer case. The reason you hear it up front is because the front drive shaft transfers the noise like a megaphone.
 

dvdswan

Full Access Member
Joined
Mar 11, 2014
Posts
2,366
Reaction score
2,035
Location
Port Orchard, WA
First Name
Dave
Truck Year
1978
Truck Model
K10
Engine Size
350
@blazink10 just an FYI, when you quote someone, you can type below the brackets. it will appear as the reply above.

Since the PO installed the manual hubs, I would urge you to verify that the part-time kit was installed in the 203.
 

RoryH19

Full Access Member
Joined
Aug 21, 2015
Posts
1,668
Reaction score
1,082
Location
Texas
First Name
Rory
Truck Year
1987
Truck Model
R10 Silverado SWB
Engine Size
350 TBI
@blazink10 just an FYI, when you quote someone, you can type below the brackets. it will appear as the reply above.

Since the PO installed the manual hubs, I would urge you to verify that the part-time kit was installed in the 203.
My 78 k10 has a 203 with manual locking hubs from the PO.
How can you verify the part-time kit is installed?
 

dvdswan

Full Access Member
Joined
Mar 11, 2014
Posts
2,366
Reaction score
2,035
Location
Port Orchard, WA
First Name
Dave
Truck Year
1978
Truck Model
K10
Engine Size
350
My 78 k10 has a 203 with manual locking hubs from the PO.
How can you verify the part-time kit is installed?

If the truck moves in hi or lo with the hubs unlocked, its installed. I would suggesting to @blazink10 to verify that there are no bad parts. I probably should have stated to open the t/case up as these kits come in all sort of different types.

He's tried everything else, if one of the parts has gone bad or the chain is stretched repairs will be needed.
 

RoryH19

Full Access Member
Joined
Aug 21, 2015
Posts
1,668
Reaction score
1,082
Location
Texas
First Name
Rory
Truck Year
1987
Truck Model
R10 Silverado SWB
Engine Size
350 TBI
If the truck moves in hi or lo with the hubs unlocked, its installed. I would suggesting to @blazink10 to verify that there are no bad parts. I probably should have stated to open the t/case up as these kits come in all sort of different types.

He's tried everything else, if one of the parts has gone bad or the chain is stretched repairs will be needed.
Thanks.
I have driven it several times with the hubs unlocked to move it around. It's a project so not much use. What I need to check is if the T-case is in "Hi" or "Hi lock".
 

Forum statistics

Threads
44,162
Posts
950,642
Members
36,276
Latest member
2manysquares2care
Top