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October 2010 Techline

Posted in How To: Tech Qa on October 1, 2010
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Better Gearboxes and Lube For '99 Explorer?
Q. I own a '99 Ford Explorer with a pushrod 4.0L V-6 and auto transmission. My first question is what ATF would you recommend I use? I was thinking about a synthetic like Royal Purple, or I was thinking about using regular ATF with an additive like Lucas Oil's.

Would a shift kit extend the life of an automatic transmission when driven reasonably? Or should I go with a transmission programmer? I haven't gone wheeling with it, but I do tow a small four-wheel trailer every weekend that weighs about 2,000 pounds, and this just kills the performance of an already sluggish vehicle. The shift kit is something that this Explorer needs very badly, as it just shifts way too soon or it doesn't downshift when it needs to, and when you tow, it only magnifies those problems. But I don't want to put a shift kit in it; I'll be ripping the transmission out to get it rebuilt in a year anyway.

My second question: My transfer case is the auto four-wheel-drive junk. Is there any way I can swap it for a non-auto T-case, maybe out of an older Explorer or Ranger, or am I stuck with the auto?

Why does my engine temperature run so cold? In the summertime, it's not a problem, but in the winter it barely gets in the normal range, and that's with the radiator completely covered and with the hottest thermostat I can find. I still get heat out of the heater, but it really kills my mileage. I thought about installing an electric fan instead of the mechanical unit. Do you think that would help my cooling problem?
Jesse Leister

A. I don't have a lot of faith in oil additives, as they may or may not blend properly with the additives that are in a certain brand of ATF. However, I am a believer in synthetic ATF, especially on a vehicle that could encounter high transmission temperatures such as when being used off-road or when pulling a trailer. Be sure to select a Mercon-rated fluid. The better lubrication and the ability to operate at higher fluid temperatures is always a safety feature.

As to the shift kit, I will also say yes. I know B&M makes a good kit and I am sure an Internet search will turn up several more companies. Yes, it will help to extend the life of an automatic transmission, as firmer shifts mean less clutch slippage, which in turn reduces heat and clutch wear. The shift kit will not cause early wear to the transmission, but it will not fix a problem if the transmission does need to be rebuilt.

As to a transfer case swap, I am sure that with enough time and patience, it could be done; however, I don't have any information on such a swap. Perhaps an Internet search on the subject will bring up some information.

Running too cold? Now that is an unusual problem. Most people complain of their vehicles running too hot. My only thought on this is that you may have installed the thermostat in backwards, or that the pressure relief valve is not at the top of the engine. Okay, one more thought: Are you sure that the engine is not coming up to the proper temperature? Have you measured the coolant temp with another gauge and compared it to what the vehicle's gauge says? Do keep in mind, if you measure the temperature of the coolant at the radiator, it will be as much as 10 to 20 degrees lower than that within the engine. The easiest way to measure the temperature would be with a thermal gun. This way, all you have to do is point and shoot, and it will give you a fairly accurate comparison.

What could be the reason for your poor fuel mileage in the winter is the same reason the rest of us also complain. One, you may be letting your car idle a lot after start-up so it will be warm when you drive away, and secondly, in most parts of this country during the winter, the gasoline you're using is oxygenated, or in other words has ethanol added to it, which lowers emissions but will also reduce fuel mileage.

The Right Tires for Stock CJ Rims
Q. I have been working on this '74 Jeep CJ-5 for my dad. We want to use the original wheels again with some new tires. Would this Jeep have come with tires that had tubes in them? We don't want to put bias-ply tires on it or anything, radials are fine. But my uncle mentioned to make sure if we re-use the factory wheels to be sure that they have a safety bead, as some tube-type wheels did not. And some tire guys are not smart enough to notice this. My uncle says that this is important because any hard side-loading could rip the tire off its bead and you will crash. My uncle has seen some guys get killed racing when they lost their tires because of radials on tube-type wheels. I can't seem to find much info on this.

Maybe it's not popular to use the factory wheels, but I think it's cool to see a stock-looking Jeep CJ-5 running around. Inside the glovebox of the CJ, the stock tire size is listed as H78x15, if that helps.
Charlie Correll
Missoula, MT

A. Just for giggles, the H78 is equal to a 225/75-15. There were a lot of factory tire options back then, so tire size could vary. The tube does not help keep the tire seated on the bead. Well, it does somewhat at low air pressure, but not all that much-it's the air that does it. Problem is that bias tires have a five-degree bead seat angle and radials use a 15-degree angle. Generally, they will just conform to the new angle, but I have been told that may or may not cause some damage to the lip just above the bead bundle. When radials first came out, people put them on bias-ply tire rims. I would be more worried about how strong a 35-year-old rim is as much as if I could, or could not, run radial tires on them.

If you're really worried, then put a rubber band made up of a smaller tube cut to fit over the rivets on the rim, and buy a radial tube to use with them. Yes, they make radial tubes. You may have to actually punch a couple of holes in the radial tire so that the trapped air between the tire and tube can escape.

I am not sure what year Jeep started using safety beads. You should be able to just look at the rim or even feel the safety bead with your fingers on an old-style steel wheel, even with a tire mounted on it. I know that in the early '60s, they did not have safety beads.

Oh, by the way, Coker Tire has lots of bias-ply replacement tires.

'70s Ford Highboy Vibration Woes
Q. I have a '76 Ford 3/4-on Highboy F-250 Ranger XLT. It has a bad vibration and I don't know where it's coming from. It has full-time four-wheel drive. I've replaced the tires and one bad U-joint, and all the fluids are good and full. Someone told me that the flexplate could cause vibration. Can you tell me something else to do or check for?

Also, how hard is it and what is the least expensive way to do a steering box conversion? I want to get rid of the lower steering box and the hydraulic ram that's on the front axle.
Danny Behm

A. Well, the first place you need is to determine if the vibration is being caused by the engine or the driveline.

Most likely, you could start out with the engine by placing the transmission in Neutral and bring engine speed up to, say, the 3,000-rpm range while parked. If you then feel the vibration, then places to start looking are a bent fan, or a worn-out fan clutch, or a bent or loose accessory drive pulley. The easiest way to check these out is to loosen the accessory belts and push, pull, and tug on the pulleys.

Yes, the flexplate on the crank-or where it attaches to the converter-does come loose on rare occasion. Remove the dust cover and check that the bolts are tightened to the proper torque between the torque converter and the flexplate. Sorry, I don't have the proper torque specs available to me, but you could go by bolt size (not head size) and locate a torque-spec chart on the Internet. As to the bolts on the flexplate to crank, well, you shouldn't be able to move the flexplate any significant distance. If they re-loosen, then that means you have to pull the transmission out to tighten them.

You said that you changed tires. Are they properly balanced, and are the rims mounting flush with the wheel hub? Make sure that there are no spring clips that hold the rotors in place-they may be interfering with the wheel's mounting surface fitting flat.

Next step would be to get the load off the driveshafts by, say, jacking a wheel off the ground and putting the transfer case in Neutral. Make sure you block the other wheels to keep the truck from rolling. Now grab the shaft and give it some hard jerks. If you detect movement, then the trick is to determine where it's coming from: the U-joints, the pinion shaft in the front or rear differentials, or the output of the transfer case. Nothing there? Then remove the front shaft and drive the truck. If the vibration goes away, then you pretty much know the problem is either a bent driveshaft or one of the driveline components that the shaft turns.

Next step is to do the same with the rear shaft and drive the truck as before.

As to eliminating the ram-style steering, take a look at You'll find an article there that has complete instructions on how to do this.

How to Fix a Pressurized Fuel Tank
Q. As a new member of your auto renewal plan, I thought I'd send your staff a rather unusual (to me) mechanical problem. I have a nice '94 Dodge SLT 1500, with the 360 engine and automatic. It has about 150,000 miles and it runs great.

When I remove the gas cap (only lately), the amount of air pressure in the (gasoline) tank is tremendous! Without threads on the cap, I believe it would blow about 25 feet. Any idea what the problem is would be much appreciated.
J. Mont in 74017

A. Okay, it's pretty apparent that you're pressurizing the fuel tank. Several things could be causing it. The first thing to look at is the fuel pressure relief valve, or maybe a kink in the fuel tank vent line. I would start out by removing the fuel tank vent hose from evap canister and apply light air pressure (3 to 6 psi) to the fuel tank filler tube. Airflow should be present at fuel tank vent hose. If airflow is not present, replace the pressure/relief valve which is at the back of the fuel tank and can be pried out with a screwdriver. Yes, you have to drop the tank to fix it.

I would suggest that you check with your dealer, as there may be a factory recall that covers this. The part number is 4002252 and costs about $26. Now I am not saying that this is definitely the problem, but it very well could be.

Older Toyota Needs New Springs
Q. I recently bought a '92 Toyota pickup truck as my first vehicle (I am 16). It has the 3.0L V-6 engine in it and it's pretty strong. I plan to use it for my small landscaping jobs as my mower/hauler, mulch carrier, etc. Problem is, the rear leaves don't really like my idea of making money too much, so they don't put any effort into carrying the loads, which results in the suspension drooping. What would you suggest as the best way to solve this problem? I hear about these add-a-leafs that you can buy, but are they any good? Please help me out!
Dar Odierna
Western MA

A. The first thing to do is determine if the rear springs are trash from being abused in the past with excessive loads. Does the truck sit level, or slightly higher in the rear when unloaded? It should. Next, just how much weight are you carrying around? A couple of lawnmowers and some grass clippings should not set the back of the truck down any appreciable amount. While the add-a-leaves will support more weight and lift the rear of the truck, they were designed to provide a suspension lift. I am not a real fan of them as they generally are a short leaf with a much more pronounced arch than the spring pack has, which forces the other leaves into a "false arch" that leads to poor ride quality.

However, as I confirmed with my Toyota aficionado Derek Emerson, your truck should have a short flat overload leaf already installed at the bottom of the spring pack that is designed to make contact with the main spring pack when a heavy load is carried. He tells me that there is the possibility that you have one or more broken leaves in the spring pack. It's not uncommon to find the # 3 leaf broken. There could also be the possibility that the former owner removed the overload leaf or one of the other leaves in order to improve the ride quality. I suggest that you take a good look at your present springs and compare them with those on another similar Toyota pickup, or look at one of the websites that sells factory-style springs such as

Where To Write
Address all correspondence to: Techline Four Wheeler, 831 S. Douglas St., El Segundo, CA 90245. You can also reach us by e-mail at; be sure to type the words "Tech Line" in the subject line. All submissions become the property of Four Wheeler, and we reserve the right to edit them for length, accuracy, and clarity. The editorial department also can be reached through the Web site at Due to the volume of mail, electronic and otherwise, we cannot respond to every reader, but we do read everything.

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