Tungsten

Yes old Nissan plastic absolutely hates heat. I had to replace many interior parts from them just turning into sand. These trucks last too long for their own good. lol

I never saw a WD21 with a 15 gallon tank. I have an archaic 91 and it has a 21 gallon capacity too. I know this because I typically fill up from half tank and get about 10 gallons in there. Maybe Nissan did have the 15 gallon option for the Z24i and KA24E engine options. I don't know. Would be cool if the OP can show what his tank looks like in the rear. Sometimes the pumps just click off too early and make you think the tank is smaller.

Don't condemn the transmission so quickly. Yes, change the filter, it should take a minute. Can't hurt anything. However the hard shifting you had is not always the transmission. A bad TPS sensor can make the transmission shift hard. If you have hard shifting again in the future, give that a look. The specs for it are in the FSM.

Normally I wouldn't downshift from like 40 mph into 2nd but I wanted to stress the transmission on purpose to see if any noises came out of it for diagnostic purposes. The 1st and 2nd gears actually have a deceleration clutch so you can cruise down a hill in them all day long. I prefer riding 2nd gear down long hills with 30 mph speed limits or lower because it avoids overheating the brakes and boiling the fluid. I guarantee that it doesn't do anything bad to the transmission if you slow down to around 25 mph first and then engage 2nd.

If you're talking about that cylinder around the shaft I don't have it. I don't even know if it's clutch related or not because there is no slippage I can feel and the gears shift nicely. I just hate things that are so intermittent and hard to diagnose. My brakes are perfect. The rotors are smooth as glass. They only have 2000 miles on them. They were recently changed.

I don't either but you know what's funny is the new U-joints and new brake lines completely eliminated it while driving. The noise isn't gone though. Looks like I got excited too early. It's still there but only when downshifting into 2nd and sending the engine to 4000 rpm when trying to engine brake. I could hear it come on and go away as the engine revs up to slow down. It's like shift to 2nd then rev then grind then it just goes away. It's crazy and now I'm afraid that it might be transmission related. Those clutch packs could be slipping and making that sound. Going to try and get a video tomorrow.

Ok I solved this problem. It was pretty interesting. I got it to a shop and they got it up on a lift and saw that some of the wheels were dragging more than others even after running the truck in 4WD for 5 minutes without applying the brakes. Surprisingly the driveshafts were perfectly in balance. So one of the mechanics asked me about the flex hoses and I just went out and got new ones made by Nichirin. Not everyone agreed with that theory in the shop but I asked them to do it anyway. Finally when I went there to get them replaced, after they changed them I went out to test it and what do you know the random occurring noise was no longer there. Basically I had slight brake drag on 2 of the 4 calipers from aging and possibly failing flex hoses. The other fun problem I noticed was that my tires started developing run out. The tires had a slight side to side shake on the lift when being run. From my online research it seems to be normal. It's not that bad where it's undriveable but it is just ever so slightly noticeable at some speeds.

4WD but I can completely disengage the front hubs and leave it in 2WD. The front driveshaft does not spin at all.

Busted rag joint most likely. Start inspecting the column where it connects at the firewall.

They have plenty of errors in their catalog. I don't know if it's their fault or the manufacturer. For example the A/C V-belt I bought from there once was too long. I think it just has to do with the fact that the auto parts industry is a pile of crap.

Yeah I'm just exploring all the possibilities now. I'm not ruling out input or output bearings either. The driveshaft doesn't have any lateral play in it but I'm going to give those bearings a second look again too. Another possible problem I saw on a Jeep forum was the rear control arm bushings having enough play in them to change the pinion angle. Also I'm going to try and make a video and look at the driveshaft in motion.

I can pop it into neutral when it's doing the noise and it instantly goes away. It doesn't change with RPMs either. I'm thinking it could be mount related too. Maybe the transmission or engine mount just slightly changes some angle enough under load for the shaft to vibrate.

How about the wiring going to the MAF sensor connector? In most cases the wiring is the issue and not the sensor itself. The rumor is that people don't remove the connector when they change the air filter so it ends up getting broken.

When your door locks have a mind of their own

At times when driving at certain RPMs and speeds, I get some crazy sounds like tapping and wobbling heard from the drivetrain. Usually it happens when the engine is under heavy load like climbing a hill in overdrive or in third. The noise most often occurs around 40 mph at 2500 rpm and 60 mph at also the same rpm. If I throw it into neutral then the noise goes away. I have already replaced the U-joints and that has alleviated the problem but the sound is still there. With the new U-joints the noise no longer happens at certain speeds that it used to happen on but still happens on some like 40 mph. What could be the next step in diagnosing this? I am thinking about putting the truck on jack stands and just watching the driveshaft. Is it possible that a weight has fallen off the driveshaft and that is throwing it out of balance? I already checked for lateral play in the shaft and there wasn't any that I could notice. There is a little lash in the gears when in neutral but that's normal. Any input should help. Thanks.

No but you can also try unplugging the oxygen sensor and seeing if the problem goes away.

Fix the leak first and fill it up with coolant. Just remembered it could be that coolant temperature sensor causing the engine to run poorly.

I like it, that extra HP is just the right amount needed for a good time in a WD21. Are there any aftermarket flat 3.3 pistons available? If I'm not mistaken, you achieved higher compression by decking the block and shaving the heads right? Just by going to flat pistons on the 3.3 over the factory supplied dished ones, you could theoretically get to the same 10:1 CR. That is one reason people go to a VG34 style bores, the VH45 pistons are flat so no other geometrical modifications are needed aside from boring. Also I know you have a stick shifter but for automatic the lower RPM power band is nicer.

You can find one of those arm rest extensions if you look in a junkyard. I have added one and it's handy because you actually get a usable storage compartment. The only problem with that is it can kind of obstruct access to the hand brake.

At 250 miles, I still have 1/4 to go! That's with some pretty spirited driving too. Anyway... LCDs don't like cold weather and the solder can break but the mechanical odometers aren't problem proof either. My old one stopped working completely because a gear broke in half. I didn't know the electrical ones like to fail too. Go figure!

*POOF* I am now tempted to stuff a QX4 airbag inside an old non-functioning appliance and blow it up.

That's no BS, the cooling system works too good even with such a thin radiator. The only issue I ever had with it was a fan clutch that always got stuck at full speed. After changing to an e-fan with a digital controller, the problem went away.

How are your front suspension bushings holding up with front LSD? From what I've heard the bushings, especially the strut rod ones, will take a beating and need to be replaced a lot sooner.

Yes that seems about right on a OEM computer. N/A VG motors are really hard to juice power out of. The OEM 3.3 are dished to reduce the compression ratio after an increase in displacement from 3.0. If you don't want to do a turbo build, custom flat-top pistons will increase power through added compression. You can use VH45DE pistons, which is a Nissan V8 but that requires you to bore the 3.3 block to 3.4 effectively creating a VG34. Another thing you might want to look into is using forged rods.