Here’s what Granville and Willie have to say on page 18-2:

Everybody talks about letting the air out of a tire for better traction and ride quality. But just how much do you let out for a given situation? Can’t tell you. Not that’s a trade secret, it’s just that there are too many variables such as terrain, speed, rim width, tire size, vehicle weight, and driving style. It’s pretty obvious that a 31-10.50-15 on a Jeep Scrambler will flex more at 15 psi than a 33-12.50-15 will when supporting a CJ-2A. 5 psi may be just right when running the sand dunes if you’re careful, but then again 8 to 12 psi (or more) may be better if you’re going to do some high speed running and jumping. Too little air pressure can cause the bead seal to break away from the rim or let too much sidewall contact a rock. Both situations could result in a damged tire and you putting on the spare. So what’s the way to learn? By doing, and watching. Lower the tire pressure in stages in different terrain and watch to see how the vehicle handles. On board air compressors are great. Wish I had one. Do keep in mind that once off the trail you may have to drive a considerable distance before you find that friendly service station, so judge accordingly.

And on page 13-6, more on air pressure in your Jeep’s tires:

The tire is a marvelous, quantitative part of yore rig. Use it as it should be used! Air those tires down when you go off the road. You’d sob spots all over your waistcoat if you could see what happens at my place in Baja.

I live on the beach. There is a lotta soft sand around. And about 50 times/year some pore, bedraggled 4-wheeler comes to my trailer with this terrible tale about being stuck. Often they’d stuck at low tide where the rig gets totaled when the tide comes in. Very sad. Time was I flew into a tizzy, got Dawg, got the rig with the winch, took shovels and the whole shot. I hardly do that any more. I slip onto my Honda 3-wheeler - or take the CJ if the guy’s gotta long way to walk - and perambulate to the scene. I check tires. Always they’re up around 30 psi or more. Over’s dead body sometimes, I air those suckers down to about 15 psi depending on’s load. Then, quite often with’s lady at my side, I fire off’s machine" and quietly with no wheel spin drive it out onto firm ground. In fact, if your lady’s good looking’ enough you might just see me, for the last time, take off down the beach, to leave you with a flea-bit Dawg and a well-worn 3-wheeler. Good trade?

I just can’t believe it, four-wheel guys stuck in sand, some of’em Jeepers! But it happens all the time. Because some guys got the notion that tires should never be de-aired; Gotta leave’em like God and Firestone intended! Ridiculous! Maybe their biggest worry is how to get the tires back up again. Because that’s the sob story I hear every time I air down a guy and save’im from total destruction in the waves. So how do we do that?

This answer is on page 8-4:

That “devil” the guys are talking about is the original engine of the WW II Jeep. If there’s a “devil” in your Jeep, you’ve got a golden oldie:

Back in 1941, ft started with this’un. A 4-cylinder, in-line, water-cooled unit with side-valve (l-head) characteristics. That’s a way to say both the intake and exhaust valves are in the block. Some people like to call’em “flatheads”. Can’t be all that bad of an idea as old Henry used’em in his Fords up to ‘52. It develops 60 hp at 4000 rpm (downhill, some say) and has a cid of 134.2 inches. Compression is low enough to burn even Baja gas, 6.48:1, and it was used from 1941 to 1953 when it was replaced by the F-head. Without the L-head, Willys, as it was then known, would probably not have won the competition for a WW II Jeep. Actually, the engine goes back to 1939 when Barney Ross worked it up for the Willys automotive line from a engine originally designed in 1928! He knew what it could do and what the Jeep (not named yet) had to have to be that thing the Army wanted. It did it. That engine still does it, all over the world. Has been known to make grown men, with fancy-new Jeeps, cry as they try to compete in rock.

In early models the camshaft was chain driven, but in later jobs (beginning Serial No. 175402, or around the year 1943) it was gear driven. This barn-burner has aluminum pistons and - a big deal in those days because not all companies had’em - replaceable bearing inserts. Oil is pumped through crankshaft passages for the main and conrod bearings. The oil pump mounts externally up at an angle through the engine with the distributor poking down into its end for drive. What a clever way to do things and to get the pump out in the open! (on most modern wimps you gotta pull the pan.)

The transmission chapter has this to say (Page 18-8):

I’m going to group these together because they’re pretty much the same. I think it is one of, if not the best and strongest trans Jeep ever used. Watch out though, Jeep used at least eleven different input shaft designs in the T-18 and nine in the T-98 over the years, depending on what vehicle they stuck it in. This trans makes for a great conversion because of its strength and compact design. Can’t really go wrong with this trans.

The T-18 and T-98 (early design, 1953-66) are basically the same transmission other than the way the mainshaft is supported. This is a fairly compact four speed transmission with a cast iron case measuring 11.87 inches long and weighing approximately 150 pounds. Its extremely strong design makes it a very popular transmission, plus the fact that it’s easily adapted to a variety of engines and transfer cases. The left side of the case will be stamped T-18 or T-98. There is a power take off access plate on the right side. It is possible to have a coverplate/shifter from a T-98 on a T-18 that was built prior to 1979. Pre ‘79 T-18s and 98s used what’s called a bellcrank shifter and had reverse gear shift pattern to the right and up. In ‘79 and above, reverse was over and down. Between ‘78 and ‘79 there was also a synchronizer size change on third/fourth gear from 2.5 inches to 2.7 inches.

This tran was used by Ford, Jeep, and IH in a variety of vehicles and styles that may or may not be interchangeable due to bolt pattern, input shaft length and rear face design.

The Ford version T-18 used in F-100 and F-350’s from 1966 to ‘84 is the most popular for both engine and transfer case conversions. It used a 6 1/2 inch long 17 tooth left hand pitch shaft with a standard Ford size 4.848 inch bearing retainer. The T-98 version (1953-66) used a larger 5 1/8 inch bearing retainer....

Well, that’s not all Granville and Willie have to say about the T-18 and T-98 trannies. But you get the picture. These guys know what they’re talking about and want to help you with your trannie problems.