I just hate it when the transmission slips out of gear. How about you?
No, not that kind of slip. I just hate it when the transmission slips out of gear. How about you?

There are a number of possible reasons this occurs.

  • Slips Out of Second
  • Bent Shifting Fork
  • Worn Gear
  • Weak Poppet Spring
  • Interlock Plunger Not in Place

For other transmission symptoms, see Transmission Trouble and Remedies on my website, www.42FordGPW.com.

This comes up so often I figured I would post the “book” answer. I hope this helps.

Interested in WW2 jeeps?  How about the history of the early jeeps that was actually written during WW2? Jeep – Its development and procurement under the Quartermaster Corps, 1940-1942

Don’t blame the carb. It is likely something else. However, after checking everything else, it’s time to look at the carb.

Failure of the engine to operate is rarely caused by carburetor defects.  If it is determined that the carburetor is responsible (that is, the ignition system is working properly and fuel is reaching the carburetor), the carburetor may be clogged or the float level may be improper.  The only adjustments the second and third echelons can make on the carburetor are adjustments of the idling speed, the idling mixture, the choke control mechanism, and the accelerator pump seasonal adjustment.  Improper adjustment should not prevent engine operation, but proper adjustment is necessary for maximum operating efficiency.

Connections Fuel Bowl Fuel seeping out around the fuel-bowl cover indicates a loose cover, a damaged gasket or casting, or a defective float valve.  Slight seepage is probably due to a loose cover. Extensive seepage is likely to be caused by a defective float valve. (Editor’s Note: The “defective float valve” could simply be the result of contaminated fuel – dirt/rust, etc.)

  1. Remove the fuel-bowl cover to examine the float.  If the float contains fuel, causing it to lose buoyancy, determine where the fuel entered the float and drill a small hole (1/8 in.) at this point. Drain the fuel from the float, and patch thfuellvle hole with a light drop of solder. (Editor’s Note: See comment above about soldering. Today it practical just to obtain a new float in a carb rebuild kit.)
  2. If the float needle valve and seat show indications of wear, replace them with new parts and new gaskets. From the specifications of the carburetor, adjust the carburetor, determine the correct float level, and set the float by bending the float support arm.  Hold the float in the closed position and blow into the fuel-line adapter.  No air should pass through the valve. (Editor’s Note: For MB/GPWs set the float with a gage or 3/8 in.)
  3. Examine the gasket.  Replace it if there are any breaks or hardened sections.  Be sure the new gasket does not obstruct any apertures in the housings.  Draw down the cover screws evenly.

Plug Caps 

Inspect all caps covering the check valves and jets. Tighten any of these that leak.  Tighten the flange nuts or cap screws holding the carburetor to the manifold assembly.

Remove fuel strainer from the carburetor or the cover from the strainer.  Wash the strainer with cleaning fluid and a brush and dry it with compressed air.  Examine strainer gasket, and replace if compressed or damaged.

Fuel Strainer

Look for leaks at the fuel-line connections.  If any leakage cannot be stopped by drawing up the union nut, there maybe a split tube or a poor seat in the union.  A damaged flare should be cut off and a new flare made with a flaring tool.  Packing with a string may serve as a temporary repair. If the fuel contains a dye, a fuel leak may be indicated by an accumulation of the dye.  But it should be remembered that he porous metal used for some castings sometimes permits a small amount of seepage, and an accumulation of dye may be due to this rather than a fuel leak. Leakage may be caused by a split adapter, in which case temporary repair can be made by soldering.  (Editor’s Note: Use caution when attempting to solder anything used in the fuel system. The parts should be cleaned of all fuel residue before attempting to solder. If you do not already know how to solder, just procure new parts!)

If you give up on your old carby then you could give a new carb a go. It’s not exactly proper and is just a replacement carb–but if you don’t have one that works it just might be with a shot. Omix-Ada 17701.01 Carburetor–I used a Solex carb for a couple of years until I could find a satisfactorily rebuilt carb. It seems like it is getting decidedly harder to find one these days.

Carb News

If you are in need of a carb you might check out Ron Fitzpatrick’s Jeep Parts as he recently started selling  Joe’s Motor Pool Carburetors.

What don’t you know about combat wheels? Come on, ‘fess up.

You might want to look at a couple of articles on my website www.42FordGPW.com :

Handling the Combat Wheel and
How to Mount Tires on Divided Type Wheels

Articles from the original Army Motors and TM 31-200.

Combat Rims!

Maybe you need some new combat rims?  You can find them available through Amazon.com! Omix -Ada 16725.02 Split-Style Military 16″ x 6″ Red Steel Wheel You will need at least four for a “complete” set and perhaps an extra one for the spare to really complete your jeep. There’s nothing like working on 70 or so year old parts–so trust working with new parts could well be worth the cost!

I like to keep clean...so I always use detergent.

I like to keep clean…so I always use detergent.

No, I’m not talking about dumping Tide ™ into your crankcase! Detergent engine oil was in use during WW2. In fact there was at least one article devoted to it in the WW2 Army Motors magazine. If vehicles were switched over from non-detergent, the article included instructions on how to proceed.

A chart from WW2 with various lubes.

A chart from WW2 with various lubes.

Using too high a grade of oil in your engine is not good for it. There are articles in WW2 Army Motors that discuss this. Higher grades then called for can cause increased wear. Hard to believe but as slippery as oil is, it still has friction. Friction leads to heat, etc, etc. Doesn’t mean that guys have used 20w50 (or whatever) for years, including myself, thinking that the wives tale of using it in a worn engine was the best choice was true.

I personally don’t think the additives do much for your engine but I don’t think generally speaking they will harm your engine. For more pearls of wisdom try reading Automotive Trouble Shooting for WW2 Wheeled Vehicles: Volume 1 and Automotive Trouble Shooting For WW2 Wheeled Vehicles, Volume 2.  These two books could help you become a WW2 wheeled vehicle knowledge wizard.

Before the US entry into WW2, the Army solicited ideas for a 1/4-ton vehicle.  The American Bantam Car Company developed the prototype that was loved by the US Infantry.  But the Quartermaster Corp has other ideas.  Maybe rightly so with worries about the size of the company and the ability to produce.  Ultimately, the vehicle that was accepted was built by Willy-Overland.  Ford participated in building the same jeep as Willys.

I love to read a good book about the Bantam, Ford and Willys jeeps- don’t you? As soon as I’m done here that’s where I’ll be, reading about WW2 jeeps!

The 1/4-ton, 4×4, truck of World War Two started out in the hands of the Infantry and a little company called American Bantam Car Company. Bantam worked with the Army’s Quartermaster Corps to produce the pilot model that was accepted and then fulfilled their initial contract for 70 trucks. During testing of the pilot both Ford and Willys-Overland were invited to check out this new vehicle. The vehicles were studied in great detail. Soon, at their own expense, Ford and Willys-Overland submitted pilots for testing too. This book covers the production prototypes–Bantam BRC-40, Ford GP and the Willys MA.

Print: $24.95 plus shipping.  Available through most booksellers.

Curl up with a good read about your favorite vehicle or a related subject!

Curl up with a good read about your favorite vehicle or a related subject!

Military Maintenance for MB/GPW Jeeps 1941-45
Information regarding the preventative maintenance, modifications and repair of the World War Two vehicles–Willys MB and Ford GPW. Vehicles that helped the Allies win the war and remain cherished by veterans and collectors alike. This volume has articles on a wide variety of subjects including special features, air, petroleum & lubrication, electrical, maintenance, Sgt. Half-Mast, contributions, rumors, paint and tires. There’s a ton of stuff in this volume–”Modern design-a new 1/4 ton trailer”, “Care of stored vehicles”, “a new rifle bracket”, “The Army’s New Paint System” and many more. Like a discussion of the fuels and lubes used during WW2 and how much gear lube should go in a differential?

Also available through most booksellers.
I edited this together from article taken from the original WW2 “Army Motors”.  I included articles related to the jeep or topics that would be of interest to jeep drivers and mechanics.