Tech Letter Of The Month
Electrifying
Question: I have an '84 Chevy S-10 longbox pickup that I am building for hunting, fishing, camping, and weekend wheeling. My plans involve a 400ci small-block, a 700R4 automatic, a 205 transfer case, and dual Dana 60s, plus a heap of electrical components. I want to run six KC lights, a CB radio, a stereo, GPS, wheelwell lights, cooling fans for the engine, transmission coolers, and winches front and rear along with a third small winch for pulling deer or bears into the bed after a successful hunt. I am planning on a dual-battery system, but wondered if I should also get a dual-alternator system? I figured I would need at least a 140-amp alternator, but wondered how I could mount two of them.
Ted, Wisconsin
Answer: I think you'll be fine with one alternator, though I would add a dual-battery setup. Check out the dual-battery kit from Slee Off Road (888.494.7533). To find the alternator you would need, determine the highest amp draw that you will be pulling at any given time and then add 25 percent. Keep in mind that no alternator can supply the amperage needed for winching without the bank of electricity stored in a battery, and as such they should be removed from the factor. But if your lights, stereo, GPS, fans, and cell-phone charger plus 25 percent exceed the 140-amp alternator you were planning on, then you should look into a high-output alternator such as the 170- to 190-amp units sold by Premier Power Welder (800.541.1817). Plus you could then add an underhood welder for backhills repairs.
The best way to understand the alternator/battery system is to consider your alternator as the stream and the batteries as the water tank where you store the water for your house (or power needed for your truck). The larger the water tank (number of batteries), the more water (amperage) you can use at your house (4x4), and then it just takes time to refill the tank (battery) at the slow pace the stream (alternator) flows. Since the alternators only flow at high amperage when needed, and under throttle you are usually fine with just one. Additionally most of the time you won't be playing your stereo while winching a deer into the bed and winching the truck out of the mud in the dark with your GPS, cell-phone charger, heater fan, rock lights, and electric fridge running, so the amp draw you need will be relatively low, and when it is high it will be for a short time. If you are dead set on dual alternators, Premier can also help you out with brackets for your Chevy engine.
Thanks for the great question, and since I think it fits our Tech Letter of the Month criteria, well I'll be sending you an Optima Battery (888.867.8462, www.optimabatteries.com). In case you don't know, the Optima Batteries are designed to last twice as long as standard batteries, offer more power in the initial engine starting steps than conventional batteries, sit unused for up to 12 months if fully charged so your trail or hunting rig is always ready, and be vibration-resistant and nonspillable so that they can be mounted in almost any position. I hope this will get you charged up to finish your project and hit the trails.
Off-Road Escalade
Question: I have a chance to buy an '02 Cadillac Escalade. I work at a body shop and a vehicle came in with body damage not bad enough to total it out, but the customer doesn't want it back. I am not interested in this vehicle for the gold trim, OnStar, XM, leather interior, or even the CD player. What has me interested is that this vehicle appears to be a 1/2-ton but it has a 6.0L V-8 H.O. and hydro-boost brakes, parts normally found on a 3/4-ton or larger truck. What really concerns me is that it has an all-wheel-drive system. How strong is this system? Can it be converted to a system that has selectable four-wheel drive (lever or pushbutton) that also has low range?
Mark W.
via 4wheeloffroad.com
Answer: The Escalade has a full-time all-wheel-drive auto-track transfer case known as an NV146. This should be easily converted to an NV246 auto-track transfer case with low range or the part-time NV243. Be sure you get a transfer case from a similar-year 1/2-ton pickup, Tahoe, Suburban, or Avalanche so that it will have the correct input gear (27-spline) to mesh with the 4L60E automatic transmission. Unfortunately there are no dash switches to shift the transfer case in the Escalade, so you will need to also swap them in from the donor truck along with the transfer case control module (TCCM).
This still leaves the problem of communication between the engine, transmission, and transfer case since the Escalade powertrain control module (PCM) will not understand how to shift the transmission when in low range. One option we would consider is taking the PCM to a local dealership and having it flashed and recalibrated to match that of a pickup truck outfitted with a 6.0L, 4L60E, and an NV243. This is entirely possible, but the dealerships may be wary to do it, especially without a VIN for a truck with these options.
Another option is to have your 4L60E rebuilt with an output speed sensor (OSS) installed and then add a lever-shifted transfer case behind it such as an NV241, or an aftermarket Atlas or Stak transfer case along with an adapter from Advance Adapters with a built-in Vehicle Speed Sensor (VSS). The PCM will read the output speed of the transmission instead of reading it through the transfer case as currently set up. Your truck should run and shift as if it were an all-wheel-drive, but it will now have a manual low range. You may end up with some "check engine" lights and codes since in low range you'll be getting a different ABS wheel-speed reading than the computer will be looking for. Again, getting help from a certified GM tech that can adjust the computers would be helpful at this point. If anyone knows of a company that can adjust late-model PCMs for these types of swaps I would love to hear from you.