"Reading" a 14-bolt Axle
Q I like that you all touched on the Rockwell 21/2-axle in the July '10, issue, as I was considering the axle for a future mod on my truck. I have an '87 Chevy extended-cab S-10 with the stock 350 four-bolt with TH350 transmission and NP203 transfer case.
We have the truck down to the frame as we are putting POR15 rust-preventive all over the new stock-but-boxed-and-welded frame, changing the stock shock mounts, and adding track bars to the rear, also swapping the 10-bolt 1/2-ton Chevy rearend with a 14-bolt full-floater 1-ton unit. I am keeping the front 10-bolt as I have not had a problem with it. Why does the 14-bolt have a stamp on the bull gear that reads "3.43"? Is this the gear ratio? I don't want to drain the good Royal Purple to count the pinion teeth. The ring gear has 51 teeth, and the other numbers on the gear are 3977-3.43. I'm trying to find out so I can sell these for some 4.88:1s so it would be a good driving gear for my 44s.
My new setup will be 44/19.5x16.5 tires, 16.5 x14 wheels, 383ci V-8 with twin 64mm turbos, TH350 trans rebuilt, NP205 transfer case (going to a doubler later), custom front and rear bumpers, winches, lights, rollbar, cage inside detailed for driving and safety, custom sound, and then put it back on the street.
Name withheld by request
A There's a pretty darn good chance that "3.43:1 is your gear ratio. However, remember it could have been changed. I have no idea what you mean by a "bull gear" other than it being the ring, or crown, gear.
You can figure the gear ratio by holding one axle shaft stationary and rotating the other shaft two complete turns while counting the number of times the pinion turns. Three and a half rotations would indicate a 3.43:1 gear ratio.
Forty four-inch tires and a twin-turbo 383 Chevy engine-just how long do you expect the 10-bolt frontend to last, or even the TH350? These would be high-priority changes that need to be made. Oh, and a twin turbo on the street in an S-10-how in the heck to you plan to cool it down with such limited room for a radiator?
How To Build a Ford GPW
Q I have a '44 Ford GPW military Jeep that I would like to re-build/re-fit with four-wheel disc brakes and power steering. An automatic transmission would be nice for the wife, but I don't think there's room. It currently has a V-6 Buick with the stock three speed and transfer case. My optimum goal would be a fun four-wheel-drive toy that can handle freeway speeds safely. Can you advise me on how to proceed?
A You asked, and what I'm going to tell you is not pretty and, most likely, a lot more money than you planned to spend. First off, you're going to need to strip the Jeep down to the bare frame, sandblast it, and weld up all the cracks that have accumulated over the last 66 or so years. It would be a good idea to reinforce several of the areas and to box the frame. Toss the axles, driveshafts, transmission, springs, and the steering to some military vehicle collector, as they just are not up to what you want to do.
Now, a lot depends on how much money you want to spend. There are lots of aftermarket front and rear axles, as well as those from donor vehicles that you could use. You will need to do some research to find something that will fit your needs and intended use, as well as price. It's the same way with transmissions and transfer cases. You have a wide array of springs and suspension types to pick from, but the easiest most likely would be a set of reverse-direction Cherokee XJ rear springs on both the front and rear, or a set of Wrangler YJ springs. Yes, you will have to build new mounts for them because of their longer length, but the gain in ride quality will be worth it. The amount of lift you chose will depend on what size tires you decide to use.
For steering, the only way to go is with a GM early-style Saginaw steering box. Naturally, a mounting bracket, steering linkage, new column and connecting shaft will have to be fabricated or bought, but all these pieces are available. A properly designed rollcage is of prime importance. You will need to do a total rewire of all the electrical components. Perhaps you might want to pick up a copy of The Jeep Bible by King/Worthy, as it deals with low-dollar swaps and easy home repairs, or one of Jim Allen's books, like The Jeep 4x4 Performance Handbook. These books can be a major help with your project.