The goal for this FAQ is to present accurate information that people will find useful.  If you have any comments concerning the content or accuracy of the information here please email me.

Last updated: 2/8/99 - v1.3
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                    CONTENTS

GENERAL INFORMATION
    HISTORY
    MODEL DESIGNATIONS
    DIFFERENCES BETWEEN MILITARY AND CIVILIAN MODELS

MECHANICAL
    AXLES
    BRAKES
    BODY
    CHASSIS
    ELECTRICAL
    ENGINE
    FUEL
    EXHAUST
    GAUGES
    INTERIOR
    STEERING
    TIRES/RIMS
    TRANSMISSION/TRANSFER CASE

ACCESSORIES
    GERRY CANS
    MILITARY WEAPONS
    TOPS
    TOOLS
    TRAILERS

COMMON MODIFICATIONS
    ENGINE
    OVERDRIVE
    STEERING
    SUSPENSION
    TIRES/RIMS
    TRANSMISSION/TRANSFER CASE

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GENERAL INFORMATION
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    HISTORY
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QUESTION:  Where did the name "Jeep" come from?

ANSWER:  Your guess is probably as good as anyone else's.  The two most popular legends are
1) since one of the WWII military designations for the 1/4 ton truck was "GP" for General Purpose, the letters were slurred together to form "jeep" [Editor's note, in truth the designation GP was actually a Ford term, "G" for  government contract and "P" for 80-inch wheelbase], and 2) it was named after "Eugene the Jeep", a character in the cartoon Popeye, that could travel anywhere and often showed up where least expected.
 

QUESTION:  Where can I get more details about the origins of the Jeep?  Books, web material, etc?

ANSWER:  The WillysTech CJ-2A FAQ has a good write-up on the birth of the Jeep.  The write-ups were posted to various e-mail lists by some of the knowledgable people on the internet.

Depends on what you mean by early history.  If you want to know about its development, the best book by far is "Jeep: Its Development and Procurement Under Quartermaster Corps 1940-42" by Herbert Rifkind.  This is chockful of accurate information.   If you want a tainted history slanted toward Willys, then "Hail to the Jeep" by A.W. Wells.  Not always accurate and downplayed Bantam and Ford's contributions.   "Hail to the Jeep" was written in 1946 and probably is the main basis where most of today's books draw on for their interpretation of history.

The WillysTech web site offers a selection of books (via Amazon.com) that describe the birth of the Jeep.

Here is a fine list to begin with  http://phaedra.apana.org.au/books.html

http://www.portrayal.com has an excellent selection of reproduction manuals for all military vehicles.
 

    MODEL DESIGNATIONS
------------------------------
QUESTION:  What do you mean model designations?  Weren't there only a couple of different military Jeep?

ANSWER:  Oh, contrair.  While not all of the Jeeps listed here were produced by Willys-Overland, they are a part of the military Jeep story and bare mentioning due to their historical significance.
Bantam Pilot Model, 1940 - the very first Jeep
Bantam BRC-60, 1940 - the remaining 69 vehicles fullfilling Bantam's initical military contract
Willys Quad, 1940 - five produced, Willys first offering to the US military
Ford Pygmy, 1940 - two delivered to the military, originated those famous flat hood and square fenders
Ford GP, 1941 - under 5,000 delivered to the military under Ford's initial contract
Willys MA, 1941 - about 1,500 produced, a transition between the Quad and MB
Bantam BRC-40, 1941 - 2,605 produced, the final Bantam motor vehicle produced
Willys MB Slat-Grille, 1942 - 25,808 produced, early Willys MB with a welded steel grille
Willys MB, 1942-45 - 335,531 produced, the familiar WWII Jeep that we all know and love
Ford GPW, 1942-45 - 277,896 produced, basically the same as the MB but produced by Ford
Ford GPA, 1942-43 - 12,778 produced, amphibious version of the GPW
M38 (MC), 1950-52 - 61,423 produced, Korean War era military Jeep, based on the CJ-3A
M38A1 (MD), 1952-57 - 101, 488 produced, first round fender Jeep and basis for the CJ-5
M606, 1953-68 - CJ-3B in military dress, used mostly in non-combat roles
M170, 1954-64 - about 6,500 produced, basis for the CJ-6 mostly used as a field ambulance
M677, 19??-?? - four door military FC170 with a 3 cylinder diesel engine
M151 "MUTT", 1959-78 - horizontal grilled combat Jeep of the Vietnam era

[information above obtained from the Jeep history section of the CJ-3B page, http://www.film.queensu.ca/CJ3B/Poster.html]
 

QUESTION:  The WWII military designations for the *Willys* 1/4 ton truck were MA and MB, presumably due to differences in the models themselves, and those are the only designations that I've heard of.  But, for the Willys produced M38 and M38A1 there were also MC and MD designations. Were both of these designations from the military or did Willys have anything to do with this naming convention?  Why the deviation from the naming standard established for 1/4 ton trucks in WWII?

ANSWER:  (For the M38) Engine serial numbers begin with "MC" which as I understand it was Willys designation for the Military 1/4 ton 4X4 3rd design.
 

QUESTION:  Web sites!  We want links to web sites!

ANSWER:
http://www.storm.ca/~seanm/miljeeps.html
 
 

    DIFFERENCES BETWEEN MILITARY AND CIVILIAN MODELS
------------------------------
QUESTION:  As the 2A is the civilian version of the MB, is the 3A the civilian version of the M-38?

ANSWER:  Try it the other way around the M38 is a militarized version of the 3A I believe the 3A began production in 48 or 49 and the M38 was made in 50 so the 3A was developed and then turned into a military jeep.  The 3A M38 connection is very close, but I would not consider the 2A a direct offshoot of the MB there was some development put into the 2A before it was released
 

QUESTION:  Did the grill drop down on the M38, like it appears the hinges allow it to?

ANSWER:  Yes the M38 grille does have hinges on the bottom.  The idea is to get the entire power pack out in one piece for maintenance or whatever.  Those hinges immediately identify the M38.
 

QUESTION:  Was the M38 sprung stouter than the CJ3A?

ANSWER:  The M38s are supposed to have both a heavier suspension and a beefier frame than the 3As, though I dont know why you would need more.  My CJ-3A has 10 leaves in front and 9 rear.
 
 

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MECHANICAL
==============================
    AXLES
------------------------------
    BRAKES
------------------------------
    BODY
------------------------------
    CHASSIS
------------------------------
    ELECTRICAL
------------------------------
    ENGINE
------------------------------
    FUEL
------------------------------
    EXHAUST
------------------------------
    GAUGES
------------------------------
    INTERIOR
------------------------------
    STEERING
------------------------------
QUESTION: What lube should I use in my Dana 25 axle knuckles?

ANSWER: Manual suggests 90wt gear oil, I believe the consensus of the list on this awhile back was to use Mobil One lube grease. You won't have to worry about spots on your garage floor and water will no longer be an issue. You can spackle most of it in when you have the knuckle apart, the fill the rest of the way when assembled. Make sure you remove any burrs on the knuckle cup...they will tear the new felt gasket and cause fluid/grease leakage.

I use high temperature wheel bearing grease in my Dana 25 front knuckles. The property you are looking for in the lubricant is a stringy texture that sticks to metal even under high temperatures. I don't know of many people still using 80-90w gear oil in their front knuckles due mainly to leaks.

I still run 140W gear oil in mine. It lasts a year or so before enough of it leaks out to matter, but I have fairly new seals.

I think a lot of it depends on whether you have freewheeling hubs. With freewheeling hubs you can put in whatever's convenient since the knuckles don't turn that much.

I don't have freewheeling hubs, so I use gear oil because I have heard that you can get cavitation with grease. They say it all spins to the outside from centrifugal force and the CV fails from lack of lubrication.

There is clearly a good deal of disagreement on this among Jeep owners and mechanics. For a while I subscribed to the mil-veh list where the consensus seemed to favor 140W gear oil. But there certainly are many who use grease.

I was thinking that chassis grease or wheel bearing grease just wouldn't splash around in there as the designers wished. Thick stuff just would get slung to the outside and kingpin bearings, etc. would suffer. Something oily is necessary like SAE 90 or 140. Possibly track roller grease like is used in Caterpillar rollers might be thin enough. My GPW just has chassis grease in it and I am afraid of what I might find when I pull it apart. These things were designed in the days when nobody cared if they dripped a little. When they quit dripping it was time to fill them up again. I generally stick with the original manufactures recommendations, or something close if it is available.

When I rebuilt the front end of my wagon I used a 600W oil. It was used in Model A rearends. It does flow and will drip but it won't get thrown out of the way. No problems in the winter either. Seemed to be the best of both worlds.
 

    TIRES/RIMS
------------------------------
QUESTION:  What kind and size tires came on my vehicle originally?

ANSWER:  NDTs (Non Directional Tread) tires.  Different models had different size tires.  The MA, MB, GPW, and M38 originally had 6.00x16 inch NDTs on 16 inch combat rims.  The M606 and M38A1 had 7.00x16 inch NDTs.
 

QUESTION: Where can I get new or used NDT tires?

ANSWER:
A place in Dayton, OH - Tires Unlimited - (937) 276-2115 has new NDT tires for $63.95 (as of 2/99)

V and K Tire [used military], Ringle WI (Wausau area)
1-715-359-6029

B and S Tire [used military], Lakeville, MN
1-612-469-2606

Wallace Wade Tires, Wallace Wade - owner
1-800-666-8973

Coker Tire,  http://www.coker.com/trucks/military.html
1-800-251-6336

Rims, new, for this same tire, Wally's Sale
414-552-8330
 

    TRANSMISSION/TRANSFER CASE
------------------------------
QUESTION: How can I get my roller bearing to fit (on the shaft)? It's too tight!

(this is an excellent tip!)
ANSWER: The center of my roller bearings fit very tight on the shaft.   So tight in fact that they would normally have to be pressed on. I used an old USAF bearing installation trick (I'm not claiming we invented it, just used it).  I put the main shaft in the freezer (lubed first) and heated the bearing in the hot sun (I finally found a use for San Antonio heat). After about an hour I installed the hot bearing on the cold shaft. The first time I did it, I didn't heat the bearing. About half way down it matched the cold of the shaft and contracted around the shaft. Stuck solidly in place. Even heated you must put the bearing all the way on the first try or it will stick in place.  Do not heat the bearings with a torch as this can burn the grease and leave carbon deposits in the bearings. I guess those of you living in the Arctic Wastelands could heat the bearing in Momma's oven at around 130 degrees. Just don't let her catch you.
 

QUESTION: I decided to tear the T-90 and Spicer-18 apart since I had it on the bench.  I need to know if there is something I should be looking for in the tranny as I take it apart next. Any tricks on disassembly or reassembly? The cone and roller bearings look ok, but should I replace them anyway?

ANSWER: You should have the shop manual that covers the T-90. I've read mine through about 15 times now getting ready to do the job. The first couple of times I read through it all seemed Greek. I thought "Surly someone has put together a better manual for this thing by now." I kept going through it and memorizing the illustrated parts breakdown (IPB) until I now fully understand each and every step. I have come to the conclusion that it is fairly complete and will work well if followed in the correct sequence. I planned to disassemble mine today but it seems my wife had other plans, I guess there's always tomorrow. If you don't have a manual it would be a great help to buy one.

See this website for assistance...  http://www.off -road.com/jeep/tech/trans/t90.html

(A descriptive suppliment to the tear-down instructions in the manual)
"A. Drain the lubricant and clean the outside of the case with cleaning solvent." Good idea to get the case as clean as possible to keep as much dirt and grime out as you can.

"B. Remove the shift housing and gasket from the top of the transmission." The instructions on the shift housing assembly stop here. As I figure out how to disassemble it, I will post to let you know.

"C. If the transfer case is attached, separate it from the transmission as outlined in Par. K-3." I didn't have to do this because mine had the model 20 transfer case that comes right off.

"D. Remove the three screws and washers attaching the front main drive gear bearing retainer to the transmission. Remove the retainer and gasket." Straight forward with no difficulty. However these screws were twelve point high torque bolts on mine. If all I had were 6 point sockets I would have had difficulty.

"E. Remove the two socket-head screws from the front end of the transmission case. These screws support the oil collector inside the case." These were also 12 point and are counter sunk. The guy that was in here last completely buried them with RTV.

"F. Tap lightly on the front end of the countershaft to loosen the lockplate. Remove the lock plate and from the slots cut into the rear ends of the countershaft and reverse idler shaft." No go sports fans.  It was easy to tap the countershaft back enough for it to release the lock plate but the reverse idle shaft was a nightmare to get tapped back. I was finally able to get a small brass hammer down inside the case and about 35 blows later (very short throw) I was able to move the reverse idler back enough the release the plate.

"G. Using special tool No. W-166 or a brass drift, drive the countershaft toward the rear of the case and remove it.  The countershaft gear set will drop to the bottom of the transmission case. If the special tool is used, the needle bearings will remain in the countershaft gear hub and the gears and bearings may later be removed as an assembly." As was expected this is all true. I drove out the counter shaft (not much force needed) and the countershaft gear set and bearings fell to the bottom.

"H. Remove the mainshaft rear bearing adapter." There was no way this was going to happen without a gear puller.  The bearing adapter was baked on tight as could be. I opted to leave it in place and just attempt to pull the mainshaft out with the bearing adapter in place.

"I. Remove the mainshaft from the case. The mainshaft assembly with the gears still in place may be removed through the rear bearing adapter opening" I was able to accomplish this with the rear bearing adapter still mounted on the mainshaft. When you remove the mainshaft the pilot roller bearings will fall out and into the bottom of the case. Collect them up so they will not be lost. I later removed the rear bearing and bearing adapter by standing the mainshaft up on end and sliding the first/reverse gear up and down on the shaft. The tapping against the bearing drove it down and off of the shaft. The bearing and adapter must later be separated by removing the retaining ring. This could have been done before, allowing the adapter alone to be removed but you would still be stuck with the bearing on the shaft.

"J. Drive the main gear into the case enough top remove the oil collector. Remove the oil collector." Stop! Do not drive the main gear into the case until you remove the outside bearing snap ring. If you do you will be driving the snap ring into the front surface of the case. After you remove the snap ring (This is the large one of the outside not the small one on the inside of the bearing) drive the gear into the case just enough to move the oil collector out of the way. My oil collector could not be removed with main drive gear installed.

"K. Remove the main drive gear." Once the oil collector is moved out of the way you can slide the gear out through the front. You can not remove it from the rear. Now I was able to remove the oil collector.

"L. Remove the counter shaft gear set and the three thrust washers.  Remove the needle bearings, and spacer from the assembly." Mine was missing the last thrust washer. There should be a total of 88 needle bearings, one spacer, six bearing group separator washers and three thrust washers.

"M. Remove the reverse idler shaft and gear by driving the shaft into the case using a brass drift." This was where it got ugly. Either my tranny is different or they (The books authors) made a huge mistake here. I was able to drive the reverse idler shaft about halfway forward through the reverse idler gear before it froze up solid. It took me about two hours with that little brass hammer to pound this shaft back out the other way. Turns out my idler shaft is larger of the rear end than it is on the front side. As it turns out my reverse idler gear's bushing is buggered up pretty bad. Not because of the pounding (although I'm sure that didn't help) but because of some small metal parts that collected inside. For those of you that don't believe in putting a magnet on the bottom I think you should think it through again. I don't know if I can change just the bushing or if I will have to change the whole gear.
[Rick S.]
 
 

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ACCESSORIES
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    GERRY CANS
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    PTO
------------------------------
QUESTION:  I plan on putting a lockout on my PTO lever to be sure that it doesn't get engaged accidentally.  If the winch clutch is engaged that might get a wee nasty real fast. How can I do that?

ANSWER: The M-38  PTO setup included a lockout that bolted onto the floor. It has a Y shaped arm on a hinge that when in the lock position would go around the PTO lever and hold it in the forward position. Flat Fenders Forever in Maine makes a great repro.
 
 

    MILITARY WEAPONS
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    SECURITY
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QUESTION: Does anybody have any suggestions for keeping an old jeep from being stolen?

ANSWER:  Do it like the military.  On the older trucks we had a length of chain welded to the body that would reach the steering wheel so you could padlock it around one of the spokes.  The HMMV had an aluminum body so they took a different approach. They put a tube under the dash next to the steering column and put a plastic coated steel cable thru the tube with a loop on the end. the bottom side of the cable was fixed so it would not pull out of the tube.  You just pulled the cable out and locked it on the steering wheel.  I like the cable & tube setup better. Neater & keeps the cable out of the way when not in use.
 
 

    TOPS
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    TOOLS
------------------------------
    TRAILERS
------------------------------

==============================
COMMON MODIFICATIONS
==============================
    ENGINE
------------------------------
    OVERDRIVE
------------------------------
    STEERING
------------------------------
    SUSPENSION
------------------------------
    TIRES/RIMS
------------------------------
    TRANSMISSION/TRANSFER CASE
------------------------------

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