4x4 AnswerMan: Truck and SUV Off-Road Tech

Dec. 28, 2012 By Jaime Hernandez, Photos by Jaime Hernandez & Courtesy of the Manufacturers
Dave and his Trooper exploring the Truckhaven Hills.

Have a truck or SUV question for the 4x4 AnswerMan? Send your questions to editor@off-road.com. Please include your name and location, and be as detailed as possible about your questions.

More 4x4 AnswerMan Columns
November 2012
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4x4 AnswerMan,

I have a 2012 Toyota Tacoma 4x4 Tx Edition. The truck came with 17" rims that I like. I was wondering if there was a 6" suspension lift kit that would accommodate these rims so that I do not need to replace them.

Hi Fernando,

Youíre in luck, as most suspension lifts should accommodate your TRD 17-inch wheels. Where it makes a difference is the tire size you choose. There is a chance that if you run a really wide tire then there will be some rubbing. I would stay away from 12-inch wide tires and lean more toward 9- and 10-inch-wide tires to make sure you donít have any rubbing issues.  If you want to go a little wider than 9 inches, you may be able to get away by using wheel spacers to correct the wheel backspacing.  Youíll have a better idea once you narrow down your search on a specific suspension kit.  Most will actually tell you the recommended tire size and wheel setup.


Off-Road Design NP205

Hello 4x4 AnswerMan,

What is the possibility of getting a 4x4 or 4x6 driveline to just operate the front axle or rear axle, only switch shifting on demand? I am trying to plan to build an amphibious vehicle that has a driveline to turn the rear axle but can be shifted to drive only the transfer case to drive front drive.

Rick Gray

GMC DUKW Amphibious 6x6 Truck.

Hello Rick,

Sounds like an interesting project Ė are you building a DUK? If you plan on using gear-driven axles, then a twin-stick transfer case like a modified NP205 or an Atlas II transfer case should do the trick. Any of these will allow you to control power to the front or rear wheels with the shift of a lever. 
More info at:

Off Road Designs - NP205 Twin Stick or Doubler

Advance Adaptors - Atlas II


An Airstream being towed by bicycle (Circa 1947).

4x4 AnswerMan,

I have a stock '99 Cummings Ram 4x4, Dana 80 / 3.55 rear axle. We pull an Airstream around. I want to upgrade the stock front discs (larger) and rear drums to disc brakes. Trying to figure out if a conversion kit is available and if switching out the axle with a newer version (post '01) with disc brakes is possible.
 Bryan Osborn

Hi Bryan,

I love Airstreams, as they are a great example of American design and ingenuity. Sounds like the piece of art requires some serious braking power. Since most of the braking on your truck is done with the front brakes (90/10), I would start by working on that first. You can upgrade to performance front disk brake rotors and brake pads that will fit directly on your truck. There are a number of companies out there that make them. This alone should make a difference.

If you decide you want to go with a larger diameter front brake rotor, be advised you may need to also get larger diameter wheels to make sure they have clearance. This option can get very pricey.

As for the rear, swapping out with a newer AAM 11.5-inch differential with disk brakes would be an option. You should be able to find them at wrecking yards anywhere from $500 to $1000. I would only do this if you find yourself needing more braking power after addressing the front. Another option would be to use a rear disk conversion kit from TSM Manufacturing (http://www.tsmmfg.com/), but these only work on single rear wheel and not dualies.

If you do a lot of towing/hauling, another thing to consider is an exhaust brake for your Cummins diesel engine. We have a Dodge Mega Cab Cummins with front and rear disk brakes and sometimes wish we had an exhaust brake when hauling/towing on steep mountain roads.

Also, donít forget to make sure your trailer brakes and brake controller are working properly. That alone will make a world of difference when going down the road.

Happy Trails!


4x4 AnswerMan,

A friend was telling me about his late brotherís 1995 Tacoma 4x4. He said it had some kind of special racing engine. He bought the truck new. It came from factory with this engine. He has had a lot of people wanting to buy this engine, not the truck just the engine. What in the world could it be?


Hi Greg,

Two things come to mind when talking about Toyota performance engines.  One, the Tacoma might have been equipped with a TRD Supercharger from the factory.  These are pricey and becoming harder to find. The TRD Supercharger on the 3.4L V6 produces a maximum horsepower gain of 75 hp at 5200 RPM and a maximum torque gain of 77 lb-ft at 5200 RPM. Peak horsepower gain is 64 hp (187 hp to 251 hp) and peak torque increase is 50 lb-ft (225 lb-ft to 275 lb-ft). The MSRP on one of these alone is close to $3k.

It could also have a racing engine from TRD.  Hard to say without seeing a photo.

You can learn more at Toyota Racing Developmentís (TRD) website http://www.toyotaracing.com/trd/


4x4 AnswerMan,

I have an 85 F-250 4x4 diesel with independent front axel and want to lift it a few inches. Is there anything I can do besides doing a full lift kit? Can I just use lifted leaf springs? Thank you for your time.

Jonathan McLain
Stevensville, MT

Hi Jonathan,

Extended shackles up front should work if youíre only looking for 1-2 inches of lift. To get 2.5 to 6 inches of lift, it will require you to swap out your front leafs with aftermarket ones. The rear can be lifted with either add-a-leaf or blocks.  Most off-road suspension companies make kits and components that will help you up to 6 inches. Anything bigger than that will require you to have custom leaf springs made. Those can get expensive. 

You should be able to fit 33-inch tires with a stock truck, and the 2.5-inch lift will give you more room under the wheel well for added clearance.  If youíre looking for 35-inch tires, the 6-inch lift is your best bet. Any tires bigger than 36 inches will require that you trim the wheel wells and bed or get larger custom leafs.

Good luck! 



Hi AnswerMan,   If my truck runs 255/70R18, and I plan to continue to run 18s on it. What's the largest size that will fit closely without needing a lift just yet? Wondering how much bigger I can go.

Hello 18-Incher,

If itís a 4x4, most trucks can get away with up to 33-inch tires, in your case a 275/70 R18. If you notice rubbing or simply would like to get a little more wheel well clearance up front, a spacer lift can be added.


4x4 AnswerMan,

I am a T2 paraplegic with a 2012 Dodge Ram 1500 4x4 and because of some medical problems I was wondering if anyone made a lowering kit for this vehicle?  Brent Davidson

Hi Brent,

Ground Force, McGaughy and Belltech all have 2WD and 4WD suspension lowering kits that will lower the front 2 inches and the rear 3 inches (also known as a 2/3) or you could go with a 2/4. Some of the 2WD components are interchangeable with the 4WD, so you could go with a 2/4 for a more level look.

It's been a while since I've lowered anything, but it can be done. Your best bet is to find a reputable off-road or suspension shop that will help you drop your truck the way you want. The best part is that you will be flying low but still have the ability to run your 4x4 if you ever need it while driving in snow or on dirt roads.

Good luck!

4x4 AnswerMan,

How big of a tire can u put on a 2004 Chevy Silverado 1500 4x4 if it has a 2 in lift on it? Also what type of mud/highway tire would you recommend?

Hi Silverado Owner,

If the 2-inch lift is a leveling kit up front, you can run up to a 33-inch tire with no issues. Just be sure to stay on the narrow side of tire sizes if youíre using factory wheels, or swap out with some aftermarket ones with added backspacing to run wider than 10-inch tires.

As for mud/highway tires, Iíd look at an all-terrain style first, as these tend to handle better if 90% of your driving will be on road. If youíre looking for something more aggressive, most new mud terrain tires on the market should work, they just wear faster and are heavier. It really comes down to availability, price and thread design you like.

A good place to start your search is with Discount Tires at http://www.discounttire.com/

4x4 AnswerMan,

I have a Ď93 Ramcharger Canyon Sport with a 5.9 fully loaded. Itís emerald green with gold detail side and bumpers. I was told it was one of 50 by my father in-law and the dealer wanted to buy it back. Also Iíve read that the ones built in Mexico did not come into the states. This one door label says it was manufactured in Mexico? What is so rare about it?

Hi Robert,

Ramchargers in general are becoming rare, but the Canyon Sport edition you have is even more so. From the trim to special color options and accessories, it is different than a standard Ramcharger in many ways. The manufacturerís label will state where it was built, south of the border for yours.

You have something special there. I suggest you get involved with one of the Ramcharger forums online to get even more information on your rig. If itís in primo condition, you might even consider having it appraised and insured for the proper value.

Who knows, maybe weíll see you and your truck on the next episode of Barret-Jackson or Mecum ... seriously.

Good luck.




4x4 AnswerMan,

I am a company driver and the antenna light on my CB goes on when I try to transmit. I cleaned the antenna mount, the flat washer, lock washer and all the other components. When I try to transmit and touch the base of the antenna the antenna light on the CB goes off. This tells me it is a ground issue. The components had road salt residue on the it. What else could be creating the grounding issue?  

Hi Dan,

There are several factors that can attribute to your CB Radio transmission problem. Best bet is to contact Right Channel CB Radios (http://www.rightchannelradios.com/) directly so they can help you with your specific problem. Right Channel CB Radios specializes in CB radios, CB Off-Road antennas (http://www.rightchannelradios.com/cb-antennas.html) and accessories for off-road drivers. 

You can read a troubleshooting article they published here on Off-Road.com that may help.

The Off-Road Guide to Troubleshooting CB Installations

Keep on rolliní.



4x4 AnswerMan,

I have a 2002 Ford F150 Super Crew with a 6-inch suspension lift and a 3-inch body lift with 325/85 R16 tires on it. I am taking the 3-inch body lift off. What size tire would be a good size to fill the gap?

Hi Steven,

So you basically have a 38" tall x 13" wide tire right now, and thatís too big for the 6-inch suspension lift. A 35-inch tire is going to be right on and will fill the wheel well nicely.



4x4 AnswerMan,

I have a 1993 GMC 2-door Yukon it has 3" body lift with 20" rims and 32" Nitto Grappler tires. To the point, when driving down the road going at any speed when you hit bumps on the road the truck doesn't absorb the bumps and it's like a thud when it hits them.  What I'm trying to say is that the truck rides rough.   Also with the steering there is no steering stabilizer on it but I am putting one on.  When riding on rough roads the steering acts crazy wanting to go one direction and the steering wheel has about 2 in of play in it. If y'all could help me and tell me what I need to do, Iíd be pleased thanks.  Brian

Hi Brian,

The rough ride youíre describing is something that GM IFS owners often experience when the torsion bars are turned too far or maxed out. Sure, youíll get more lift, but at what price.  If you can live with dropping your truck 1 to 1.5 inches from where it currently is, you will notice much improvement with the ride. 

If you still have the factory torsion keys in place, consider replacing them with leveling torsion keys from ReadyLift or Cognito. These will allow you to properly get lift while correcting the degrees of torsion so it doesnít ride rough. Even then, donít max them out if you want a smooth ride.

As for the wandering wheels, a proper alignment should help, but first address the torsion lift. The wheel alignment can be done at the same time.

Good luck.

Have a truck or SUV question for the 4x4 AnswerMan? Send your questions to editor@off-road.com. Please include your name and location, and be as detailed as possible about your questions.

More 4x4 AnswerMan Columns
November 2012

October 2012

September 2012

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