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December 2010 Techline

Posted in How To: Tech Qa on December 1, 2010 Comment (0)
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December 2010 Techline

Wants Turbo 475 for SM465 Swap
Q I have a tough manual transmission in my Jeep, an SM465, and an NP205 transfer case. I want to replace the manual with an automatic TH475 from an '81 Chevy Van C60. Is there an adapter on the market to match them? If so, could you tell me what manufacturer (Advance Adapters, JB Conversions, or Novak) could have it (serial number, etc., so I can order a kit)?

Is the TH475 similar to the TH400 automatic? (I mean length, bolt pattern, etc.). I know the 475 is for towing and usually found in GM heavy duty '80 trucks. Does the TH-400 to NP 205 adapter work for the TH-475?
Jorge Beecher
Neuqun, Patagonia
Argentina

A Yep, the TH475 is very similar to the TH400. It's kind of the heavy-duty version, with more clutches, straight-cut gears in the planetary unit, perhaps a slightly lower First gear, and a few other changes. They also have one of the nice heavy-duty aluminum bottom bellhousing covers with built-in brace bosses that connect to the sides of the engine for more trans support, just like some of the 4x4 versions have.

I spoke with Advance Adapters tech guy Steve about this, and he said that their standard TH400 adapter will work just fine. They sell quite a few to guys using the Cummins BT4 engine/TH475 combination out of delivery trucks in 4x4 conversions.

I don't think that it is necessary for you to go to the extra effort to locate one of these transmissions, but if you have access to one, go for it. Only Advance Adapters (www.advanceadapters.com) offers this adapter, and the part number is 51-3202.

Drivetrain Swap Tips for Wrangler YJ
Q m looking into a complete drivetrain upgrade for my '94 Wrangler. I have an '84 Blazer donor truck. The small-block 350 is an easy answer. However, the NP208 transfer case and GM 10-bolt 8.25-inch differentials are another matter. Is it worth buying gears, lockers, and disc brake kits for these axles? As well as spring pads, etc.? How strong are they really?

Should I scrap the '84 Blazer and find a Dana 44 or 14-bolt rearend instead? I already have installed a Skyjacker 6-inch monolinear suspension lift, rear disc brakes and a transfer-case output shaft shortening kit.
Cliff Roundtree
Raeford, NC

A Well, let's start with the small-block first. Generally speaking, engine swaps are not emissions-legal unless the engine is from the same model year or later than the vehicle it's going in. Being in the military, you may end up being stationed in a state with emission checks, and you may not be able to license the Jeep.

I don't think that you're really gaining anything by going to the GM parts other than a lot of work. The track will be considerably wider, with the tires hanging way out of the fenders. (Some states really frown on this.) You will also have to buy new wheels, as the GM axles use a six bolt pattern. With all the work you have done to your Jeep at the present time, why make the axle swap? The present Dana 30 frontend and (hopefully) Dana 44 rear can handle 33-inch tires with no problem under reasonable use, and 35s with an axleshaft change. I think that you would be money and time ahead if you keep your present drivetrain and upgraded it with better axleshafts, true locking differentials and such.

"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
Via email

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?
Leonard Coon
Temecula, CA

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.

Super Duty Steering Wander
Q I have a 2000 Ford F-250 Super-Duty 4x4 with the V-10 and automatic trans. I purchased the truck new, and it is used as a farm truck. It has regular maintenance performed on it. The truck has 100,000 miles on it. Lately, as I drive down the road, it tends to wander from one side to the other. I had the local Ford dealer put in new ball joints and align the frontend. I have also tried two new sets of tires, and the pickup still wanders. Is there a bad seal, or something in my power steering or steering sector that could cause this?
Dennis from Iowa
Via the Internet

A I get a lot of questions very similar to yours. Okay, it's a farm truck. I grew up farming, so I know just how much hard use the truck is getting. Most likely, one or more of the steering components is worn. You were right in replacing the ball joints, as there is a factory Tech Service Bulletin out on that subject. Hopefully the mechanic replaced the lower ball joint with the greaseable lower ball joint (p/n 1C3Z-3050-AB) and replaced the upper joint with the current replacement part (p/n F6TZ-3049-AA). I would think that the dealership that put in the ball joints and did the alignment would have noticed if there was any wear in the other components. But then again, if his work order just said, "Do an alignment" that's all he is going to do.

Let's start at the outer ends. The uni-bearings your truck uses may be at the end of their useful life. Jack up one front wheel at a time off the ground, naturally with the truck secured from moving. Sit down and grab the top of the tire and give it a good hard shake, in and out. You should get no to (maybe if you shake hard enough) a slight, but very slight, movement of the wheel/tire. Any movement means it's time to replace that uni-bearing.

The next step is to crawl under the front of the truck and have someone turn the steering wheel back and forth, with the engine off, just enough to take the slack out of the steering but not enough to move the tires. Watch for movement in the tie-rod end and in the sector shaft of the steering box. Where there is excessive movement, you have found the problem.

The problem could also be caused by sagging of the front springs, which would change the caster angle. Not enough front-axle caster could very easily cause a wandering problem, but then again, if the tech did an alignment he would have caught that as well as the loose bearings. How about the condition of the spring eye bushings? Watch for spring movement when the steering wheel is moved back and forth. Check to see if the U-bolts that hold the axle to the spring are tight.

And one last thing: go to the rear axle-yes, the rear axle. If it is moving around from a worn spring eye bushing or loose U-bolts, it could be causing the wandering problem.

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