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August 2012 Techline Tech Questions Answered

Posted in How To: Tech Qa on August 1, 2012
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Differential Dilemma
How do I tell what differentials and gears I have in my ’89 Jimmy fullsize? Is it alright to put lockers in the stock axles?

To figure out what gears and differentials you have in your truck you have a couple options. If you think the axles are stock you can take your VIN number to the dealership parts counter and they should be able to tell you what is in the axles. If you think they have been modified you’ll generally have to pull the diff covers to find out what differentials and gears are in the axles.

In most cases you can put lockers in the stock axles as long as you don’t drive too aggressively and you stick to moderation when selecting tire size.

Favorite Fords
Do you know of any website that specializes in older trucks? I have a standard cab, longbed ’78 Ford 4x4. I have been looking for custom bumpers and things you can get for the newer trucks today but I want to know if they make any for older trucks like mine.
Tyler Barnes
Cottonwood, AS

Jeff’s Bronco Graveyard ( is a great place to start.

Wagon Wheels
Will the wheels from a ’05-up Ram Power Wagon fit on an ’84 Dodge ¾-ton?

Yes. All of the older eight-lug ¾- and 1-ton trucks use an 8-on-6.5 lug pattern, same as the ’05-up Ram power Wagon.

However, be sure to check for clearance on steering arms, brakes and so on. The Power Wagon wheels have 6 inches of backspacing so they will tuck in pretty far. Since they are 17s, they may be big enough to supply the clearance you need.

10-Bolt Blunder
How large of tire can a stock 28-spline GM 10-bolt front axle live with? What are the best options for an upgrade and what is most likely to break? I would like to run a locker and 38-inch tires. Do I need to swap in a Dana 60 or can I build up the 10-bolt?

Is it possible to successfully run a 38-inch tire on a 10-bolt front axle with a locker? Yes. Would I recommend it? No.

The biggest factors to consider are your driving style and the kind of terrain you plan to attack. If heavy rocks or lots of wheelspin (mud and steep slick climbs) are planned then don’t waste your time with the 10-bolt. You will be throwing your money away. Your best bet is to upgrade to a GM 1-ton Dana 60 front axle. Good news is that it’s pretty much a direct bolt-in swap.

Now if you only plan on mild trails you can give the 10-bolt a shot, but if that’s the case do you really need a front locker?

Max Gas SUV
I need to be able to tow a 4-ton armored vehicle with the appropriate trailer using a 4x4 SUV. I’m looking for a used vehicle, between the years 2000 and 2005 with a gasoline engine. Do you have any brand/model suggestions? Towing capacity suggestions? Engine size suggestions? MPG is not a concern.

If it has to be a gas SUV you have two options: The Ford Excursion with the V-10 and the ’05 GM Suburban 2500 with the 8.1L and 4.10:1 gears.

The Excursion maxes out at 11,000 pounds tow capacity when optioned properly. Look for the 6.8L V-10 gas engine.

The Suburban 2500 should have a tow capacity in the neighborhood of 12,000 pounds when optioned properly.

With an 8,000-pound towed vehicle you’ll want to find a 14,000-pound trailer. One of these will weigh about 3,500 pounds. So you need a rig that can haul 11,500 minimum. With that kind of capacity requirement you are reaching into the 3/4- to 1-ton vehicle segment. You might want to consider a crew cab ¾- or 1-ton pickup.

Loose Hose
Where does the hose go that’s on top of the output housing on an NP208 transfer case? When I bought my ’86 Dodge W150 this hose was tied off in the engine compartment.

It’s just a breather hose. Keep it above the depth of any planned water crossings.

Wheel Wonderings
I have a stock ’06 4x4 Toyota Tundra four-door with a V-8. It has factory rims and tires on it now. I added a leveling kit to the front and new shocks all around. I would like to install bigger wheels and tires but do not want to add a lift kit at this time. Any ideas on what size wheel and tire I can go up to and still be able to turn the wheels without the tires rubbing on something? Also, steel vs. alloy? Why one over the other, if both are available in the same color and style.

With a leveling kit you can typically upsize your tires one to two sizes.

Stick with aluminum wheels. They are lighter. Less rotating weight means better fuel economy, acceleration, and braking.

Domino Power Adders
I am looking into installing a Banks Ram-Air system in my ’04 Wrangler. Do I need to mess with the chip?

Nope. A cold air intake is the most cost-effective bolt-on power part you can add to any gas engine all by itself. It does not require any additional electronics.

Air Over Coil
I have a ’90 Ford Ranger I have played with in Iowa, mostly mud with all stock parts except 33-inch tires. I want to start playing in Oklahoma and South Dakota. I bought a V-8, a Dana 44 front axle, and a Ford 9-inch rear axle to swap in. Should I go with coil springs or air shocks? I want to have coil-over shocks but they are out of my budget.
Dustin Allison

For what you have planned either will work. The air shocks will be easier to mount; the coils will be less complex and less expensive. If you go with air shocks, make sure they have plenty of rebound damping. Doing this will make the truck more stable on climbs and descents. Air shocks are best used on lighter vehicles so if you plan to really load the truck down you may want to go with the coils.

Dana 80 Envy
My ’77 Chevy ½-ton has a 12-bolt rear axle; I want to put in a Dana 70 or Dana 80. Will a Dodge Dana 80 rearend fit? Was there ever a Dana 70 or 80 for the front?

While you could make a Dodge Dana 80 fit in your GM truck, a much easier swap would be to go with a GM 14-bolt from a similar era GM ¾- or 1-ton truck. It’s pretty much a bolt in swap and nearly matches the strength of a Dana 80.

Light-duty truck Dana 70 front axles are pretty rare. In most cases they have old and antiquated brake assemblies making the axles not worth swapping. However, there are some modern medium-duty Dana 70 and 80 front axles out there. The only bummer is that they typically have a ten-hole lug pattern which can be difficult to match out back. For more info about new Dana 70 and 80 front axles check out Dana Crate Axles (

If you are determined to install Dana 70 or 80 front and rear axles, Dynatrac ( can build you custom axles that will fit your truck.

Axle Welding
I have to replace some front axle mounts. Can I weld the control arm mounts to the axle without disassembling the axle? The mounts I’m currently looking at are beefed-up factory-style mounts from 4WD Hardware. Can these simply be fabbed by a shop or should I just go with the beefed-up factory-type mount? All work will be done by a quality shop.
Robert Shirley

Yep, you can! It’s best to control the amount of heat you put into the housing by only welding small sections at a time to avoid any warping. However, you really shouldn’t weld mounts directly to the cast center portion of the housing for strength reasons. If you need mounts in this location you should get some sort of truss/suspension bridge to attach them to. Ruff Stuff Specialties ( offers truss brackets that work well for this.

As far as custom-built or store-bought brackets: You can go either way but it’s typically less expensive to go with pre-fab mounts. It saves a lot of shop time costs.

Sloppy Steering
I have an ’83 Chevy on 9 inches of lift and 39.5-inch Swampers. It has an HD Dana 44 front axle and a 14-bolt rearend but the power steering is way loose. Is there any way to make it tighter?

You’ll need to check the linkages and tie rod ends for wear. Also inspect the ball joints and wheel bearings for slop. Inspect the steering box mount for cracks as this is a fairly common problem on ’73-’87 GM fullsize 4x4s. Lastly, inspect the steering box (at the sector shaft) and the steering shaft for slop. The easiest way to inspect most of these parts is to have a buddy saw the steering wheel back and forth with the vehicle parked (engine off) while you look for loose, broken, or worn components. Anything suspicious should be replaced or rebuilt.

Solid Axle Swap
I have an ’81 Ford F-150 regular cab, longbed, automatic with a 5.8L engine. I am going to be swapping out the suspension and driveline for 1-ton components. I have never done this kind of thing before but have heard of it being done. Do you have any tips or can you point me in the right direction before I get to ripping and tearing away the old parts?

While it’s not really a good project for a first timer it can be done if you have extensive welding, fabrication, and chassis experience. Jeff’s Bronco Graveyard ( has the parts you need to make the swap, including the axle. This particular conversion uses the older C-bushing-style radius arms for simplicity.

Smoggy Honcho
I have a ’77 Jeep Levi Honcho shortbed pickup. It has the 360 V-8 in it. I bought it from a guy out here in Vail, Arizona. There are no dents and the tailgate is in perfect condition. The only problem that I have is that the person that I bought it from had taken off all the emission stuff. We used to have a junkyard here that did Jeeps, but he went to other pastures. Do you know where I can find the parts? I can’t get tags until it passes emissions.

How do you feel about the 401? I really like the torque that they put out in low, low. I call it tank mode. But I am also thinking about putting in a 350 Chevy in the ’77 Jeep.
Doc Dowidat
Tucson, Arizona

I’m not totally sure what was factory for smog equipment in 1977. But, if I remember right, in Arizona you only need to pass a sniffer test, no visual. So if that’s the case (and even if it isn’t), I would recommend the smog-legal Howell Fuel Injection (

Your 360 will run way better and cleaner than the carb ever did and you don’t need any of the related smog stuff except maybe the air cleaner and the hot air intake. Plus, if it is just the sniffer test, dump the factory ignition system and get a Performance Distributors ( Davis Unified Ignition (DUI) distributor. Then open up the plugs a bit for a hotter spark.

With the EFI and the new ignition you’ll think you have a totally different engine under the hood.

The 401 is cool but hard to find and all of the AMC engines can be expensive to rebuild. I’ve been pretty happy with my 360, but I’m not really a hotrodder. Swapping in a GM V-8 ain’t cheap either, and may not be the most cost-effective option when you add up exhaust, add-ons, and the cooling system. The little stuff adds up quickly.

One Wheel Peel
I have a ’00 Silverado Z71 and I cannot figure out why the front tires will not lock and pull. I have already replaced the front axle motor/actuator due to it not working before. I can hear the axle motor and transfer case engage. Prior to replacing the axle motor, I could not hear it engage.

I put the truck up on jacks and put the truck in 4-Lo. All four tires turned at the time, but when I put the truck back on the ground, the front tires will not pull.

Can you help me with this?

If you have it on jackstands and all four wheels spin then the front drive is working fine. However, maybe you are mistaking the function of your open front differential for the front drive not working. Only one front wheel will spin if you get the truck in a twisted up or stuck situation. An open differential will cause the tire with the least amount of traction to spin.

2 By 4 Too
I have a two-wheel-drive ’88 Chevy Suburban. I want to make it four-wheel-drive. A friend is giving me a ’94 Chevy 2500 4x4 pickup rolling chassis for free and I am trying to figure out if the 4x4 system on the truck will fit the Suburban. Also the sub is a ½-ton. The truck is ¾-ton. Normally I would just build the ’94, but it is beyond repair—the only usable part is the drivetrain.

It’s not really a cost effective swap. The two frames are very different.

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