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October 2005 4x4 Tech Questions - Techline

Posted October 1, 2005

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Question: I own an '82 CJ-7 with a 4-inch BDS lift and I think a 2-inch shackle lift. I run 33-inch tires and have 4.56 gears. My front is a Dana 30 with Warn axles and an ARB locker, and the rear is a Model 20 with Genuine Gear one-piece axles with an Auburn posi-traction. Could I get away with running 35s, or should I stay with the 33s? Most of my four-wheeling is on trails rated 3 to 4.
Les Jones
Lincoln, CA

Answer: There are several people I go four-wheeling with who run 35s with their Dana 30 frontends. Two have stock axles; the other is equipped with Warns. The one went with Warn axles after breaking some stock pieces. They all do some pretty serious four-wheeling. However, all are excellent drivers with a very light foot and they think before they act. And yes, they do run 4-rated trails.

My recommendation is to always use a Dana 44 with 35-inch tires, but even I don't always follow my own recommendation. I have been known to run 33s on an old Dana 25 axle and have it live. Again, it has a lot to do with just how heavy a foot you have, and your driving style.

The rearend should be just fine with your upgrades. The biggest weakness of the AMC rearend is that the lightweight axletubes sometimes bend. But you have to be using the vehicle pretty darn hard for this to happen.

Question: I have a '93 Chevrolet K-30 crew cab with a 350 engine. I would like to build a 383 for better towing performance. In the interest of heavy-duty use and longevity, I would like to use a set of marine-duty heads that I have. They're the late-model Vortec type with insert valve seats for all valves, bronze guides, sodium or inconel exhaust valves (I'm not sure which), and rotators on all valves.

What is your opinion of this setup, and will the rotators have any effect on coil bind in the valve springs? I plan to use the Chevy cam PN 14097395 with 0.431/0.451 intake/exhaust lift.
Ken Bell
Scappoose, OR

Answer: Sounds like a great combination to me. I doubt that is enough cam lift to cause any coil binding. Under hard use such as towing or marine duty, the valve seats and guides are the first to wear out, so your new engine should last a long, long time with those heads.

Question: I have an '01 Cherokee Sport with the 4.0L six and AW4 four-speed automatic transmission. It is a great vehicle, in fact almost perfect, except that the downshift from Second gear to First cannot be controlled with the selector in the First/Second position. Too many times, especially in low-range, Third is too fast and First is too slow.

Jeep offers no fix for this, and I have tried one aftermarket device produced in Oregon that supposedly will prevent downshift into First with the flip of a switch. It did that alright, but it threw the transmission control module into a "limp home" mode; no lockup or no Fourth gear without stopping the vehicle, and shutting off the engine to allow the module to reset. The manufacturer found the unit not to be defective. I was told that perhaps the module programming had changed for 2001, thus causing the incompatibility.

Are you aware of a remedy that works? What about transplanting a transmission from a Wrangler or Grand Cherokee?
Gary Van Heese
Emmett, ID

Answer: You're not the only person who hates the AW4's shifting characteristics and there is not a lot you can do about it other than to swap transmissions, which is going to be a major pain. I'll assume that you want to keep an automatic and a Fourth gear overdrive? How it's all going to be compatible, electronics-wise, is a guess by anyone. But it just may be doable.

As I see it, you have two choices. The first comes from Chrysler, the model 42RE used in the Grand Cherokees from 1993 to 1998 and some '99 models with the 4.0 six-cylinder engine. (The V-8 models have a Chrysler bolt pattern, not the old AMC pattern like your engine does.) Try as hard as I could, I couldn't find any information as to output transmission spline to input transfer-case spline compatibility between the two automatic transmissions, but it's a good guess that they are the same.

Your second choice and perhaps maybe the best, but most likely more expensive, would be to go with a GM Turbo 700R4. It's a stand-alone transmission, so there are no computer controls. It does use a TV cable to control shifts, so you'll have to possibly fabricate a bit on linkage on the throttle assembly. Both Novak Conversions and Advance Adapters have the proper adapter plate between engine and transmission and transmission and transfer case.

The new transmission combination will be a bit longer, so depending on ride height, you may or may not need a slip-joint eliminator kit to solve driveshaft angularity problems. You will also need to either relocate the ignition crank position sensor into the 700R4 bellhousing or swap to a front crankshaft-mounted unit.

The most difficult part of the swap may be in obtaining the proper clearance in the transmission tunnel, as the 700R4 is a bit larger in size.

Best of luck and whichever way you go-let us know how it turns out.

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