• Government Liqudation

  • Latest Threads Activity


    LED lights

    Thread Starter: Finallygotone

    Hey you all, I have some LED light that are 12 volt, is there any place that I can tie into to use only 12 volt instead of 24V, thanks ahead of time,

    Last Post By: jjmartinez1982 Today, 01:00 Go to last post

    What have you done to your FMTV or LMTV today

    Thread Starter: Coffey1

    Painted mine today pictures soon

    Last Post By: fuzzytoaster Today, 00:57 Go to last post

    interesting Pic

    Thread Starter: eaw46

    I have not seen this one before sorry if you have.

    Last Post By: Crapkin Today, 00:38 Go to last post

    M35a2 Wont start

    Thread Starter: DalekEngineer

    My M35a2 won’t start, it will almost start while cranking but won’t. Yesterday it would be a little hard to start but when it got running it ran good

    Last Post By: gimpyrobb Yesterday, 23:17 Go to last post

    A1R Warning about gauges

    Thread Starter: m-35tom

    If you have an A1R do not try to test the voltmeters on dash. They are not voltmeters, they are indicators driven by CAN data from a ECM or ECU. Do you

    Last Post By: m-35tom Yesterday, 23:15 Go to last post

    Thinking about pulling the Deuce Trigger Again

    Thread Starter: 71DeuceAK

    As the title says, I may find myself ready to take the plunge before much longer. Work is picking up and I may be somewhat well funded by the end of

    Last Post By: davidb56 Yesterday, 23:07 Go to last post
  • CUCV Wiki

    Wiring Diagrams are located in Appendix F of the -20 and Appendix E of the -34

    PLEASE READ the first few pages of the Troubleshooting Section for an explaination of how to read the wiring diagrams

    Your first best place to go for information is always to the technical manuals that are available for free download as searchable/printable .pdf files. There is a wealth of information and it is written for the common military man.

    First read the Operator’s Manual. This will answer most of the newbie questions that arise on this forum. Then read the Lube Order. This will give you answers to the most common questions about fluids and capacities. Then read the Unit Maintenance Manual. This will give step by step instructions for basic troubleshooting and repairs. If you can’t find what you’re looking for in any of those, then read the Intermediate Maintenance Manual.

    The parts manuals will give you schematics followed by a listing of part numbers. You can cross-reference these in the index at the end to find the NSN. Then you can google the NSN and usually find more information.

    An additional useful outside resource is http://www.tpub.com Sometimes the TMs will refer to other obscure bulletins and publications. These can often (not always) be found at tpub.com. tpub.com also has information on most NSN’s, including who the original manufacturer/supplier was for the item. This may aid you in tracking down obscure parts.

    1. What glowplugs for a manual conversion, no controller card or anything except a switch, a relay, and the plugs? AC60's or Wellman 070's?
    If your truck is stock then get the Wellman plugs, if its been converted to 12volt get the AC's.

    2. What size freeze plug heater?

    3. Where to find a fuel fired block heater?

    Fuel System

    • Diesel, of course. #2 Diesel does not have the same lubricity properties as older varieties. Many users recommend a diesel additive. Most commonly used/available is Diesel Kleen/Power Service or Howe’s. Use with discretion/at your leisure/at your own risk.
    • Fuel filter is NAPA# FIL3136; FRAM#P3940A
    • An alternative spin-on filter is available and requires a base and some minor changes. There are numerous threads that cover this topic if you choose to go this route.


    • Oil is 15W40 for diesel. (HD 30W works very well in hot ares) Rotella is available in gallon jugs, and quarts at just about any convenience store or truck stop. Engine capacity is 7 quarts.
    • Oil filter is Stock Filter is AC PF-35; FRAM# PH5; WIX 51061; NAPA# FIL1061; K&N# HP-3002;BOSCH# 3510
    • Oil and filter change recommended every 3 months/3,000 miles


    • Engine coolant is any standard ethylene glycol. The Lube Order indicates a 50/50 coolant/water mix for normal use; or 65/35 if temps are -10F or colder.
    • System capacity is listed as 25 qts.
    • Drain, flush and fill every 2 years, or 24,000 miles
    • Hockey Puck Thermostat - NAPA 381-190, Autozone 42995, Orielly 42995

    Transmission (TH400, 3-Speed)

    • Transmission fluid was indicated as Dexron II. This has been replaced with Dexron III.
    • Transmission filter is NAPA# ATP14558 (or 19701 w/gasket); FRAM# FT1020A (w/gasket)
    • It only takes 1 pt. to raise the level (hot) from “add” to “full”.
    • Capacity is listed as 4 qts., but this may vary. Fill as needed to reach level. 9 qts. when changing filter and cooler lines.
    • Drain/Fill and replace filter every 2 years. Do more frequently if regularly using off-road or for towing

    Transfer Case (205 & 208 )

    • Fluid is Dexron III
    • Capacity is listed as 5 qts.
    • Level should be approx. 1/4” below edge of filler plug hole
    • Drain and fill every 2 years/24,000 miles, or annually if under heavy use

    Front/Rear Differential

    • Fluid is standard GO (Gear Oil, 90/75)
    • Front capacity is 4.5 pts.
    • Rear capacity is 5.4 pts.
    • Only the M1028 is listed as requiring additive. Additive is GM.

    Brake Fluid

    • Fluid is DOT5 silicone only. CAUTION: Some of these vehicles may have been filled with DOT3. There are numerous arguments for using either kind. However, do NOT mix them.
    • Level should be ¼” below lowest edge of each filler opening in master cylinder
    • Check monthly

    Power Steering

    • Fluid is standard power-steering fluid.

    Air Cleaner/Filter

    • Any standard filter designated for use in a K5/K30 should work. FRAM# CA3492 (or PRA3492); NAPA# FIL2096 (or 6096); K&N# E-1690 (expensive, but worth it!)

    Glow Plugs

    • DH recomends AC Delco AC60G glowplugs and installing new 1/4" terminal ends on your wires
    • Wellman 070 (original 3/16" terminal) direct fit replacement
    • Wellman 050 or AC 60G glowplugs (1/4" blade terminal)
    • Control Card/Controller is available from Antennaclimber
    • GP Relay is NAPA# ST85, Advance Auto #S603 (AA is much cheaper)

    Rear Main Seal (2-piece neoprene)

    • NAPA# FPGBS40529


    • For the M1009 the stock tires are Goodyear Wrangler ATs 31x10.50-15
    • All other trucks use the stock size of 235/85R16E per the TM 9-2320-289-20p parts manual.

    Belts ( all but M1010 )

    • Driver side alt- Gates# 25-7575; Dayco# 15580
    • Passenger side alt- Gates# 7483; Dayco# 15490
    • Power Steering- Gates# 7448; Dayco#15455

    When installing Gatorbacks, I (LavaRok) choose the following three belts:

    • Driver side alt - 15585 ( 58 )
    • Power steering - 15461 ( 45.5 )
    • Passenger side alt - 15491 ( 48.5 )

    However, the P side alt was tight. I'd try the 15495 ( 49 ) next time.


    • Group 31 or 6TLs
    • Really any 800+ cca batteries will do

    Starter relay

    • AC40 (stock) - For a more dependable starting system, update your starter system with the Doghead Relay upgrade. This replaces the subpar relay with a heavy duty relay. It will save your starter from burning up. NAPA# SME 7018601.

    Injector Pump

    • The IP is a Stanadyne Roosa Master DB2
    • The estimated life is 100,000 miles. However, keep in mind that these vehicles are 20+ years old. The seals are almost certainly shot, or about to go.
    • If you are leaking fuel from the bell-housing cover, it is likely drain off from the IP through a hole in the rear of the engine compartment
    • The first seals to go are typically the o-rings on the throttle shaft. You may notice a dripping from the L-shaped arm attached to the spring on the driver side of the IP. Seals are only a couple bucks, but replacement is a 4-hour job at minimum, requiring the removal of the air-intake manifold, CDR valve, loosening the vacuum pump, and possibly removing the fuel injector lines and removing the IP.
    • Rebuilt pumps are usually in the $3-500 range (plus $300 core charge if you don’t give them your old IP core). Take-off pumps can be had for around $100, but will eventually encounter the same problems. Getting your IP rebuilt is probably the best thing you can do for the longevity of your vehicle.

    Lights/Blackout Lights

    • The right toggle switch moves power to the service lights, horn, dash, etc. or to the blackout lights. Pull it out and flip it up or down.
    • The left switch turns on the blackout drive light. Flip it up or down; it will return to center position.
    • If your lights suddenly don’t work, check the toggle switch.
    • Then check the fuses.
    • If it’s neither of the above, you’ll probably have to trace circuits to track down a short somewhere.


    The M1008 is a 1984 K30 pickup with a J code 6.2L diesel, TH400 3 speed automatic, and a NP208 transfer case.

    The M1008 has a Dana 60 front axle open and Corporate 14 bolt rear axle with 4.56 gears, detroit locker.

    The M1031 is a 1984 K30 chassis cab pickup with a J code 6.2L diesel, TH400 3 speed automatic, and an NP205 transfer case. The NP205 transfer case is used because it has provisions for a PTO to be installed on the vehicle to power various auxiliary bodies that might be installed.

    The M1031 has a Dana 60 front axle and Corporate 14 bolt rear axle with 4.56 gears, a detroit locker in the rear and a limited slip in the front.

    Most M1031s are Contact Maintenance Trucks with an aluminum box containing a PTO driven 10KW generator, air compressor and welder. The generator installation has a governor installed on the engine to maintain 1800 RPM to get 60Hz power regardless of load.

    Some M1031s had a bed installed and were redesignated M1028A1s

    The M1028 is a 1984 K30 pickup with a J code 6.2L diesel, TH400 3 speed automatic, and an NP208 transfer case. It is primarily used as a shelter carrier and therefore has heavier rear suspension and mounts for a communications box to be installed in the bed.

    The M1028 has a Dana 60 front axle with limited slip and Corporate 14 bolt rear axle with 4.56 gears, Detroit locker.

    The M1028A1 is a 1984 K30 pickup with a J code 6.2L diesel, TH400 3 speed automatic, and an NP205 transfer case. It is primarily used as a shelter carrier and therefore has heavier rear suspension and mounts for a communications box to be installed in the bed. They typically start life as an M1031 chassis cab and have the bed added.

    The M1028A1 has a Dana 60 front axle and Corporate 14 bolt rear axle with 4.56 gears, with a limited slip front and Detroit locker in rear.

    The M1028A2 is an M1028A1 with the addition of dual rear wheels and rear sway bar, all other specs are the same.

    The M1028A3 is an M1028 with the addition of dual rear wheels and rear sway bar; all other specs are the same.

    The M1010 is a 1984 K30 chassis cab with a J code 6.2L diesel, TH400 3 speed automatic, and a NP208 transfer case. It is fitted with an ambulance body and a special 200 amp charging system. The rear of the cab is cut to allow passage between the truck cab and ambulance body. The M1010 is also used as a mobile command post and small shop in some units.

    The M1010 has a Dana 60 front axle and Corporate 14 bolt rear axle with 4.56 gears, detroit locker.

    The M1010 has a special charging system and air conditioning compressor installed to supply the ambulance body with cold air.

    The M1010 charging system uses two Leese Neville 100 amp alternators running to an external voltage regulator (the 'blue box') and is prone to having problems maintaining the 12 volt system's charge. Some units removed the system and replaced it with a standard CUCV charging system, with varying degrees of success.

    The M1009 is a 1984 K5 Blazer with a 1 Ton J code 6.2L instead of the normal C code 6.2L diesel and a TH400 3 speed automatic instead of the TH700R4. These modifications were done at the miiltary's request to make all engine/transmission components the same between the 1008 and 1009 trucks.

    ****The front springs are 3 inch wide 56 inch long and the rear springs are 2 1/2 inch wide 52 inch long. . *****

    The M1009 has Corporate 10 bolt axles front and rear with 3.08 gear ratio and a Gov-Lok in the rear. The front axle is open.

    Troubleshooting Information
    Note: Do not convert your CUCV to 12V else you will be totally on your own as no one will be able to help you! The 24V system works perfectly as is and is easy enough to work on as long as you follow the TM's!!!

    Glow Plugs
    Tools Required

    • Multi-Meter / test-light
    • Glow Plug Socket
    • 3' piece of wire, with ends stripped

    1. Remove a wire from a glow plug. Have a helper turn on the key, and check for voltage between the glow plug wire and ground.
      • If voltage present, use a test light and hook the end to the tip of the glow plug while its still in the engine. With the other end of the test light, touch positive. If test light lights up the glow plug is good. Do this for each 8 glow plugs.
      • If no voltage continue

    2. Locate Glow Plug Relay on firewall to the left of the master Cylinder.
      1. check for voltage on the Left large terminal.
        • If voltage present, have helper turn on key, do you hear a clunk from the relay?
          • If no, take your piece of wire, hold one end on a good ground, and touch the other end to the small terminal with the BLUE wire.
            • If you still dont hear the relay clunk, replace it.
            • If you do hear the clunk, your controller card is bad. Replace it, or install the 'manual glow plug' setup.

        • If voltage not present, check for voltage on the left side of the resistor bank (behind air cleaner on firewall)
        • If no voltage, check wire feeding resistors to ensure it is properly connected to the TOP busbar on the firewall
        • If voltage present, verify wire between resistor and relay. if wire is good, replace resistor, or do the 12v resistor bypass. Always do the resistor bypass to get 12 volts to the 12 volt glow plugs, otherwise you have 13 plus volts or more such as when one of your glow plugs fail or a connector at the glow plug is loose!

    Charging System
    Dual 100 amp alternators. Batteries are wired in series to make the 24V. Very strong charging system that will handle any load you can toss at it. Changing over to 12V is NOT recommended.

    The passenger side alternator MUST HAVE an isolated ground. The driver side does not. An Autozone part number for the DRIVER side alternator is DL7157 (also found in a 1975 Cady with a V8 engine). This alternator is 78 amps and works just fine. You MUST have an Isolated Ground Alternator for the passenger side. Ebay, www.saturnsurplus.com, and many other places stock this alternator.

    NAPA has a remanufactured Isolated Ground Alternator, part number WIL 90014277. Wilson Alternator rebuilds them. Cost ~$220. Just make sure you test the alternator before you install it. They have had some issues with the rebuilds of NOT being isolated grounds.

    27si Type 100 Series


    The factory starter for the 6.2L engine is the 27MT Direct Drive 24v unit (GM part# 1113591). Rebuid kits can befound at www.aspwholesale.com. Specify 24v when ordering. Wilson has a rebuilt starter WIL 91014376, available at NAPA, Oreilly's and other locations. Price is around $230

    GM replaced the direct drive with the 28MT Gear Reduction starter (GM# 10479611) in the late 80s early 90s. The original units where made in Japan and are used on a lot of different equipment. Most of the ones you will find on Fleabay are made in China. Quality may not be up to standards. Buyer beware. Wilson also sells a rebuilt unit WIL 91014417. NAPA, Oreilly's, etc. You can get rebuild kits from www.aspwholesale.com

    Be sure you change the starter bolts with factory ones, install the "correct" support bracket and bolt the bracket to the block.

    DD - direct drive
    GR - gear reduction
    starter bolt - 15544950
    bracket bolt - 14060613 - M8 x 1.25 x 20 - hardware store
    starter bracket DD - 14028931
    starter bracket GR - 23502557
    DD rebuild kit - http://www.aspwholesale.com/index.ph...productId=6174
    GR rebuild kit - http://www.aspwholesale.com/index.ph...productId=5977
    DD rebuilt 24v starter - Wilson WIL 91014376
    GR rebuilt 24v starter - Wilson WIL 91014417

    The stock starter is 24V but can be changed to 12V.

    To convert to 12v, move the wire that goes to the starter (big red one) off the junction block on the fire wall and moved to the + side of the first battery. This should be done only if a 24V replacement can not be found. With the 24V you have the power of both batteries, with the 12V only the first battery. Also, you need to remove the under dash starter relay and connect the Purple W/White tracer wire to the purple wire.

    Headlight Blackout System
    12V sealed lights. On some you may be able to replace the black out drive light in the grill but all the bumper lights are sealed.

    Repair Guide

    Rear main seal replacement without removing engine
    Autozone rear main ~ $22
    Autozone oil pan seals ~ $12

    Here are the steps I took:

    1. Jack up front end frame, to raise frame slightly off axle. Even an inch will help.
    2. Drain oil, remove filter.
    3. Unplug batteries
    4. Remove starter
    5. Remove bottom access for bell housing, tricky since tranny cooling lines have to be pushed over a bit, no need to remove the lines though
    6. Pull oil pan, may need to loosen a line for the front axle breather from frame rail, tends to block access to front bolts on oil pan. Use a screwdriver to gently pry the pan loose from the engine block if it sticks; which it should if RTV was used.
    7. Remove oil pump/pickup
    8. Remove rear main bearing cap
    9. Remove old seal
    10. Install new seal, carefully. I had a helper and with 4 hands we were able to hold it in place while applying pressure to push it in the grove. Take note of placement, mine was labeled which side points out. TM shows a shim which can be made to assist in seal install. I'd be wary though as you don't want to damage the seal.
    11. Following the TM, use anaerobic sealing compound on the rear main cap as specified, install rear main cap and torque to spec.
    12. Reinstall oil pump/pickup
    13. Clean old gasket from oil pan and engine block. RTV oil pan gasket to oil pan, let sit for 10 minutes, RTV top of gasket, let sit a few minutes; then reinstall oil pan while trying not to get RTV places it should not be.
    14. Reinstall bell housing access cover and air breather line for front axle if removed.
    15. Reinstall starter
    16. Install oil filter
    17. Fill oil, check level, etc.
    18. Reconnect batteries
    19. Start it up, recheck oil level after idling for a few minutes and verifying no leaks.

    That is about it! If anyone sees a step I missed, please edit this. As long as you have another vehicle to drive in case the job takes longer than you hoped; you'll be fine to try it yourself. It took me two days, maybe 7hrs total. First day, I setup doing steps 1-5. Once you pull the oil pan, you will want to finish through step 13.