Hey guys I am new to this board and need some help with my new truck. I just purchased a 1976 gmc ¾ ton sierra grande about 3 weeks ago. This is my first old 4x4 purchase and I am in need of some help. I have experience with working on and repairing vehicles, so I do have mechanical knowledge, but just not much on 4x4’s. I believe I have the np203 t-case in my truck, I have not crawled under to make sure however. The truck does have manual locking hubs and the Lo Loc, Lo, Neutral, Hi, Hi Loc shifter indicators. I believe a full time conversion has been done, but am not guaranteed on that. I read on this board that it is important to flip the hubs and drive the truck in 4 wheel drive mode every once in a while to keep everything lubed properly. So, that is what I did today on my way to work and that is when my problems began. Here are the issues I came across.
Side note: The truck rides on 35” wild countrys on 16” rims, and has a lift on it (not sure how much).
Prolems
1. When the hubs are locked and driving in Hi Loc there was a loud clunk coming from the front drivers side wheel when taking a right turn, and only a right turn.
2. After making a turn the vehicle pulled dramatically in the direction the turn was made. It took a little doing/counter steering to get the truck to drive straight, however after about 5 seconds or so the truck would drive straight as an arrow once again.
3. After accomplishing these 2 first to problems in only 3 blocks or so, I pulled over to shift the vehicle back into the position I had been driving in for the 3 weeks I have owned the vehicle (HI I believe, is it possible to drive the vehicle in neutral?). I shifted the transmission into neutral and tried shifting the t-case through all 5 settings, but stopped when it sounded and felt like it was grinding into gear (such as a manual transmission makes when you don’t depress the clutch). It went into neutral find but trying to shift into LO or HI again I got the grinding noise. I then tried to shift the vehicle transmission into park but received a slight grinding noise when trying to shift through reverse into park. The grinding and noise would not persist/repeat itself after turning off the ignition and starting it again for either transmission shifter or t-case shifter.
So go ahead and tell me the scary truths, or your ideas, and how much it might cost to fix these problems if you have past knowledge. I can handle it, I didn’t pay much for the vehicle and plan on fixing it up and keeping it for a long while. I love the truck and have no direct plans to part with it. As I said previously I have owned this truck only for about 3 weeks and it has run like a champ. Drives, great and starts up on the first of second try no matter the temperature, or if it has sat for a couple days.
Thanx for all your help guys this board looks like an awesome source for knowledge and assistance with my beloved truck.
Nate
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