Straight talk from the TL tech team

Ground Glitches

We have a 1994 Chevy 3500 dually powered by a 7.4-liter gas engine and automatic transmission with 38,000 miles on it. We purchased it with 12,000 miles on the clock, and it has had an electrical glitch the whole time. As long as the engine is running, whether sitting still or traveling down the road, the voltmeter needle bounces around from 12 to 14 volts and the fuel gauge varies up to nearly half of the gauge's range. The voltmeter will sit at about 13.5 for a while, then maybe drop to 12, then up to 14, etc. It doesn't bounce wildly, just maybe two or three times per minute. My dealer changed instrument clusters three times under warranty and also replaced the alternator; it didn't cure the problem. This all happens whether the lights are on or off, and the brightness of the lights doesn't vary when the voltmeter jumps. We pull a 32-foot trailer, but the problem occurs with or without the trailer MIKE & ANGIE MCINTOSH CAMBY INDIANA

This is a fairly common problem with GM light-duty trucks. The fact that your lights don't vary with the fluctuations in the gauges is a good indication that the trouble is in the gauge circuitry, not in the charging system. Whenever you have an in-dash voltmeter that seems to be acting up, simply connect a portable voltmeter to the battery and watch it along with the dash gauge. In your case, I believe the solution will be found in the connections on the back of the gauges or in the ground connections. Since the cluster was replaced several times, check the printed circuit carefully for cracks and if that doesn't help, run a separate ground wire from the cluster to a good chassis ground. Also check the battery-to-chassis and engine-to-body grounds.

Truck-Camner Matchup

I need help trying to figure out what size camper I can get for my truck. I have 1992 half-ton Chevrolet Silverado with the V-6, automatic, shortbox and extended cab. I'd greatly appreciate any help you can ive me on this.

BRANDON MEYER VIA THE INTERNET

This is an easy one, Brandon. In short, I can't recommend you use your truck to haul a camper. Virtually all self-contained campers on the market will weigh more than your truck can carry without exceeding the truck manufacturer's gross vehicle weight rating (gvwr) once the truck, camper and all your cargo and passengers are loaded. At best, you may find a stripped-- down, fold-down camper that's lightweight enough, but hardwall campers are out, as far as I know.

There are several reasons for this. First, there's camper weight and truck gvwr. Weigh your truck with a full tank of gas and any passengers you intend to take along when using the camper Next, look at the truck's gvwr on the door jamb sticker. Deduct the truck's weight from the gvwr, and the remainder is its payload capacity.

Say the truck weighs 5,500 pounds and has a 7,500-pound gvwr. Deducting 5,500 from 7,500 leaves a 2,000-pound payload capacity. The combined weight ofthe camper, its options, cargo, fluids and so on can't exceed the truck's 7,500-pound gvwr. If it does, the truck is overloaded. Likewise, the truck's rear axle gross axle weight rating (gawr) tells you how much weight can be carried on the axle. If the combined weight of the empty truck plus the camper exceeds the gawr, the axle is overloaded.

There's also the question of the truck's suspension. With a typical camper aboard, your relatively soft half-ton suspension may make the truck feel like a heavily loaded sailboat in a stiff breeze with afollowing sea. You'd probably need to add air springs or some other suspension aids to beef up your suspension for safe driving manners.

If you're determined to press ahead with this, be aware that some camper manufacturers tend to be a bit fanciful when it comes to weight labeling. For example, the camper's unloaded vehicle weight (uvw) label may say 1,400 pounds, but that probably doesn't include options like the awning or air conditioner and it may not include water or propane, to say nothing of the cargo you'll be adding. A camper's weight adds up fast once you start to consider all the goodies that go along. If your truck has, say, 1,200 pounds of cargo capacity, you'd need to shop for a camper in the 800- to 900-pound range to allow for passengers, cargo and the like, and there aren't many Topic suggestions are invited. Write to: RV Clinic & Performance, Trailer Life, 2575 Vista Del Mar, Ventura, California 93001 (no phone calls, please). Selected letters will be printed, but unfortunately time does not permit individual replies.

campers that weigh that little these days.

Finally, there's your V-6 engine to consider That engine likely does a right spunky job of hauling the empty truck around and can manage a very small trailer as well, with the right axle ratio for towing, but you'd be slow on the hills, on acceleration and so forth with the V-6 and a camper aboard. If you really want to use a camper a switch to a larger truck with a V-8 is definitely a better way to go.

Hangin' in There

I have a problem with my 1997 Ford F-250HD 2WD with 7.5-liter engine, E4OD transmission and 4.10 rear axle. It has about 16,500 miles on it. I tow a 27-foot fifth-wheel that weighs about 9,500 pounds loaded.

The transmission works fine when the truck is empty. However, when I am towing and top out on a hill that I have pulled in second gear, the transmission hangs up in second gear and won't shift automatically. I must either remove my foot from the accelerator and then push it down again, allowing the transmission to shift with no load, or move the shift lever to SECOND and back to DRIVE. I tried letting the engine rev to see how far it would go before shifting, but it hangs in there to more than 4,000 rpm.

The mechanic at my dealer says to live with it. I took the truck to another dealer last week, which could not find any electronic problems. I don't feel I should have to live with an automatic that I have to shift like a manual. LARRY SWENSON LOGAN, UTAH

It seems like your transmission has a faulty sensor; probably either a manual lever position sensor (MLPS) or a vehicle speed sensor (VSS). The MLPS tells the computer what gear the driver has selected with an analog signal. Sometimes these sensors give false signals that confuse the computer and cause all sorts of weird symptoms like you describe. Tracing the problem may require a transmission scan tool with a snapshot mode that can be replayed in the shop after the road test. Stabilizing Jacks & Holding- Tank Heat

We recently bought a '97 Sportsman 30-foot travel trailer It came with four scissors-type screw jacks, one at each corner. We were told by the dealer to treat these as stabilizers, and not levelers. I've seen the same type of jacks advertised in catalogs as stabilizer/levelers. Why shouldn't we use these as levelers instead of having to use blocks to raise the tandem wheels?

We're also interested in advice you have on winter camping. Our freshwater tank and plumbing are all within the heated living space; however, the gray-- and black-water tanks are not. What can I do to prevent these tanks from freezing, while still allowing them to be used?

KURT KNURR LAKE IN THE HILLS, ILLINOIS

A local ski area in New Hampshire allows trailer owners to rent sites with sewer and electric hookups. I have a Coachmen 22-foot travel trailer, and I'm considering leaving it there for the season and commuting each weekend to ski.

How do I handle the black- and graywater tanks to keep them from freezing? Should I insulate the tanks and purchase one of the tank heating mats I see advertised in your magazine?

Also, how do I prevent the window condensation that occurs each morning in the trailer? If plastic sheeting is the solution, should it be installed on the inside or the outside of the windows?

DONNA CASSIDY VIA THE INTERNET

Most stabilizer jacks are simply not designed to lift the weight of the rig, Kurt, which is what's needed when a jack is used for leveling. I'd stick with the leveling blocks and use the jacks for steadying the trailer body. To level the rig, you'd need to use the jacks sold by HWH, BAL, RBW Industries or other companies, as they're designed to handle the extra load.

Use of an aftermarket electric heating pad or mat, which attaches to the flat surface of the holding tank and is powered by 120-volt AC shore power is the best way to prevent the tanks from freezing. If you can also add insulation around the tanks, such as pieces of polystyrene foam fastened to the bottoms and sides of the tanks, so much the better, because it'll make more efficient use of the warmth provided by the heating mat. As for dump valves and assorted plumbing, using standard residential-style heating tape or cord can help prevent freeze-ups.

There are several do-it-yourself "storm window" kits available at home-supply stores. These come with adhesive or clip-- type fasteners, and should be installed on the inside of the windows to help deter condensation. Due to the moisture expelled into the air via your breathing, as well as a result of propane combustion on the stove, the air inside your RV is often quite moist during the winter when windows typically are kept shut tight. That moisture in the warm interior air is going to condense on the cold windows, and even the extra added-- on plastic won't be completely immune from condensation. Use of a residential dehumidifier will also help remove moisture from the air.

Dodge Diesel Tip

I have a 1994 Dodge Ram 2500 pickup with the Cummins 5.9-liter engine and five-speed manual transmission. We tow a 30-foot fifth-wheel trailer much of the time. I noticed the truck wasn't making as much power as it used to, and I took it into the dealer for a checkup. I was told it needed a new turbocharger because the waste-gate actuator was bad, and that I would have to pay for it since the truck was out of warranty. This is a lot of money, and I'm not sure the dealer is on the level with me. Do you have any advice? TOM LAMONT HousToN, TExAs

The waste-gate on a turbocharger can malfunction in one of two ways: It can release pressure too soon, which results in low power, or it can fail to release excess pressure, resulting in overboost. Dodge has recently released Technical Service Bulletin no. 11-08-98, dated September 25, 1998. The TSB, which applies to 1994 through 1998 models, states that a new kit has been released that allows technicians to repair turbos with failed wastegate actuators. This could save you a lot of money. Also, check your engine warranty. Although your truck body may be out of warranty, the engine should still be covered, unless you have more than 100,000 miles on it.

Fifth-Wheel Hitch Weight

We have a 1994 Dodge 2500 WD with the 5.9-liter engine. 3.55 sears, automatic transmission and, we believe, an 8,600-pound towing capacity. What would be the maximum fifth-wheel hitch weight this truck can carry? We're looking at a new trailer with a 1,250pound hitch weight, a 6,800-pound base weight and a 9,250-pound gross vehicle weight rating (gvwr). Should I be concerned about this 650-pound overloaded condition?

DAVID BATES OQUAWKA, ILLINOIS

To determine how much hitch weight your truck can handle, David, you deduct the truck's rear axle weight (the truck's rear wheels on the scale only, loaded fora trip)from its rear gross axle weight rating (gawr). The remaining amount is how much hitch weight the truck can handle before becoming overloaded. For example, if the truck has a 6,000pound rear gawr and its rear end weighs 3,500 pounds, then 2,500 pounds would be your load-carrying capacity on that axle.

Your truck will become overloaded if the combined weight of your trailer, its contents and any passengers in the truck exceed the 8,600-pound tow rating. You also need to keep the gross combination weight rating (gcwr) in mind. Gcwr is the maximum your truck and trailer, loaded, can weigh without being overloaded. The gcwr for your truck is 14,000 pounds, so when you weigh your rig loaded and ready to go, it shouldn't weigh more than 14,000 pounds. The trailer's gvwr is the maximum the trailer can weigh, fully loaded and ready to go, without being overloaded.

The figure you should start with is that 6,800-pound base weight number. If by base weight you mean dry weight or unloaded vehicle weight (uvw), then that figure will include the added weight of propane and factory options included in the trailer. Your best bet is to take the trailer to a public scale and weigh it. If that's not possible, find out what options are on the trailer and add up the weight of those options, then calculate the extra weight of any fluids that will be added to the unit. That figure is the wet weight.

You'll also need to estimate how much cargo you may be carrying in the trailer and the truck, because that weight also must be deducted from the tow rating. As long as the total weight being towed and carried in the truck does not exceed your truck's 8,600-pound tow rating, and you don't exceed the truck's gcwr, you won't be overloaded.

Copyright T L Enterprises, Inc. Jun 1999
Provided by ProQuest Information and Learning Company. All rights Reserved