Towncivilian

See page 67 (section 2-14) of the owner's manual. Looks like there's some sort of 4LO light.

It won't cause the code, but it might have something to do with why your trans doesn't downshift with the accelerator floored. Adjust it following the instructions on page FE-3 of the FSM. You'll need a 14mm wrench.

Which sensor are you referring to, revolution sensor? That one would throw a P0720. Is there a lot of slack in your accelerator pedal? Adjust it following the instructions on FE-3.

My automatic has HG46 if I remember correctly; I'll have to check next time I have the hood open.

I wouldn't worry about it. If your post relevant to the topic, I can't imagine why anybody would get annoyed at the bump. I'm not a moderator here though, so take my reply with a grain of salt.

I might be wrong here, but couldn't one swap in either an HG43 or HG46 geared H233B and not worry about gear ratios at all, since both are paired with the R200A front differential from the factory?

Laxman's 2001 R50 LSD Modification and Install

What? R50s with rear discs? There was no factory option for discs on any year R50, and I've only seen pics of one or two rear disc swaps and I don't know how that was achieved.

The gear ratio is on the certification plate on the passenger firewall. HG43 = 4.363 ratio, HG46 = 4.636 ratio.

Usually the dual GL-4 and GL-5 rating refers to its use in differentials, not transmissions. Although, this thread on BITOG seems to prove otherwise (unless my reading comprehension is way off).

If that RP 75W-90 is GL-5 rated, you don't want to use it in the trans or transfer case since GL-5 fluids can harm brass synchros in the trans. Use a GL-4 fluid only for the trans/tcase.

http://forums.nicoclub.com/how-to-conect-ipod-mp3-directly-to-factory-system-2001qx4-bose-6disc-head-unit-t482374.html

That one can be a pain in the ass due to the weird angle for the bulb socket... I siphoned out some brake fluid from my reservoir today since it was overfull after brake pad replacement.

The fuel-related component you describe sounds like the fuel filter. Misfiring rarely has anything to do with the catalytic converters, but constant misfiring over a long period of time will severely harm the cats. Can you get the current engine codes pulled at an auto parts store like AutoZone? I'd start with replacing the distributor, cap, and rotor.

I have a 2WD open diff.

Many gear oils already come with LS additive; it'll be stated clearly on the bottle.

Here is a topic which describes the specific changes to the RE4R01A-HD model transmission in detail.

Rubber bushings, zirconium heating elements on O2 sensors, and lubricated parts (if seals fail and excessive wear occurs) are acceptable cases of wear items, especially after 100,000 or more miles, countless heating cycles, constant dirt/water/road grime attacking rubber, etc.

I haven't done it myself. I'd install a coolant filter, but the heater core hoses on my 2001.5 R50 are in a poorly accessible position. As far as I know, if the filter gets clogged, there won't be a significant drop in oil flow since it's not a full-flow filter. The Amsoil setup is really more suited for engine oil bypass filtration and requires some drilling. This "cheapo" setup doesn't require any - just the filter, its base, hoses, hose clamps, and a tool to cut the existing hoses with. The Magnefine really is the simplest way to add decent filtration to the transmission fluid circuit. Even if it goes into bypass, ferrous contaminants will still be caught by the magnet. I'd say the only failure point is if the bypass fails to function (if the filter is installed backwards, or it is defective). If it's a defective bypass, I'd imagine Magnefine would owe you a new transmission. See pictures of a Magnefine unscrewed with 23,000 miles on it here.

I was referring to the transmission pan.

Here's a crappy Paint diagram: I hope this makes more sense.

Air filters actually get more efficient as they load up with dirt. If you clean the filter too often, you are letting more dirt past the air filter. See here for more details. Maybe do a pan drop to check the condition of the strainer?

See AX-4.

That is an overcomplicated install; you can tee both the inlet and outlet lines for the transmission cooler into a spin-on filter mount and the differential pressure between the lines will create a "bypass" filter, filtering only a small portion of the fluid at any given time. If the filter clogs, no big deal. This has the advantage of being able to use a much finer filtering media in the range of 3 microns or less. Stick several hard drive magnets on the exterior to catch ferrous debris and you're set, just change the filter once in a while (first change early, maybe, since it'll load up with contaminants fairly quickly) and transfer the magnets over. Such a setup can also be used for filtering coolant; tee the heater core inlet and outlet hoses and use a specialized coolant filter (without SCA additive) and base (generally 11/16" threaded), but I digress at this point.