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Needing some advise


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I just bought this 1985 Nissan 720 4x4 a few months back When I saw it and found out the guy was scrap the truck. The only thing wrong was 2 busted ball joints and busted sway bar links. Other then that we hooked a battery to it and with a little help of starting fluid it cranked right up after sitting for 5 years. I replaced the fuel pump and that's all I've done to keep it running. While I was fixing the front suspension I replaced both shocks, upper and lower ball joints, sway bar links and upper A arm bushings. Its my daily driver with the exception of the fuel filter clogging but I haven't had time to drop the tank and clean it out.


What I want to build a decent looking and functional 4x4. I do a lot of trail riding and this is my first 4x4 I've owned. If there's any advise anyone could give me about this trucks weak and strong points.


This is also my first ever post on any forum on the internet. Once I figure this out on my phone I'll post some pictures. Thanks in advance.

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It's the hidden things that are rarely thought of or checked. For one you know nothing has been checked in over 5 years and possibly not for much longer than that. So drain and replace...


Transmission oil. Two liters GL4 80W90. Make sure it's GL4 or 'yellow metal safe' to protect the brass sinchro rings.

Trans case. Same as above. The T-100 is a good unit but makes noise if abused. Check oil level regularily.

 Front and rear differentials. GL5 80W90 EP gear oil

Synthetic is good but has a tendency to start leaking when put into old vehicles with worn seals. It's that slippery. I would just use regular gear oil.


Steering box, Probably on a 4X4 it's powr steering. Check and top up with ATF. If discolored you should replace.


Engine oil and always change the filter. Expect to spend over $6 for a good quality Wix brand. I use a 15W40 Delo or Rotella brand oil. Just tell the guy at NAPA that you want protection for your "flat tappet cam" and he'll know you want more ZDDP in it. For added oil supply keep your eyes open for a D-21 Hardbody with either 4 cylinder Z24i or KA24E or KA24DE. These three motors have oil pumps with 13% larger (internal) rotors for much more volume output. This raises low RPM oil pressure. I can't praise them enough. My 300km L20B had a hot oil pressure of 17 PSI at idle. Installing a used KA24E pump, it went up to 29 PSI with no other changes!


Fuel filter. Carry one in the glove box untill you drop and clean that tank. There is a filter in the bottom of the electric fuel pump too so keep it clean. The pump relies of fuel to cool it. 4x4-ing tends to stir up crap in the tank.

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I'm gonna do that oil pump thing next weekend. I blew the head gasket the other day. It hasn't ran hot at all .I did forget to mention a few things in my last post. I have replaced all the gear oil in the truck except the front diff. I couldn't see the drain plug lol. It also is missing the termostate so the truck is damn near impossible to run hot. I'm parking it until then. But when I pull the head off I'll take a look at all the valves and head surface. I work In a local shop so I have all the right equipment to measure clearances and surfaces and such. I'm also replacing the entire timing set and I know about the oil pump now so I'll replace that to while the engine is torn down. At the moment I'm not looking for high performance but just to keep it running strong. I did find out the guy I bought the truck from had a weber carb for it. He just doesn't have the adaptor plate.


Thanks again for the reply. Not many of these trucks on the road anymore and its hard to find anyone that knows anything about them.

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