4x4 AnswerMan: Truck and SUV Off-Road Tech

Mar. 23, 2012 By Jaime Hernandez
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:
February 2012

January 2012

December 2011

 

MANUAL OR AUTO?
2012 Toyota FJ Cruiser - Trail Teams Special Edition

4x4 AnswerMan,

Looking at buying a 2012 FJ Cruiser. Never off-road before but looking to do some. Drove a stick my whole life. Wondering what is better for off road. Years ago every one said a stick is better for this but many people say that the automatics have caught up. Please some helpful advice!

Thank you,
Michael

Hi Michael,

Glad youíre getting into off-road. There are some benefits to an automatic that are hard to beat on- and off-road, like not having to shift gears and pump the clutch in traffic or on the trail.

The advantage to having a manual transmission, especially if you will be doing trails that require a low gear ratio to crawl, is having more control and power.

The FJ Cruiser with 6-speed manual transmission has a crawl ratio of 41.84:1. The FJ Cruiser with Automatic transmission has a crawl ratio of 33.66:1. As you can see, manual would be better for crawling and technical off-roading.

If youíre already a stick-shift driver, and arenít looking to change, then why change?

They are both good, it really comes down to driver preference and the type of terrain you plan to tackle. 

Good luck on your purchase!

Below is more information on the 2012 Toyota FJ Cruiser drivetrain.

Source: Toyota Motor Sales U.S.A. Inc.

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DODGE RAM AXLE SWAP
Dynatrac Free-Spin Heavy-Duty Hub Conversion Kit
Hi 4x4 AnswerMan, I have a 2003 Dodge Ram 2500 was wondering what axle I can swap for one with locking hubs that will be easiest and also about the approx. cost  Hi Richard,

No need to swap out axles. If youíre serious about locking hubs for your Dodge Ram, then we recommend you take a look at Dynatracís Free-Spin Heavy-Duty Hub Conversion. It takes your existing American Axle Manufacturing (AAM) Model 925 and turns it into a manual hub lockout system. 

It will save you time and money trying to adapt a front Dana 60.
 
More info at http://www.dynatrac.com/products/freespin-dodge/freespin-dodge.html

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BIG RUBBER FOR MY SUPER DUTY

Hey 4x4 AnserMan,
I have a 2001 Ford F-250 with a 4" leveling kit on it and 35s on it now. I was curious how many inches of lift would be required to clear 39.5" tires? If you could answer this for me it would be greatly appreciated. I donít want to try and take the word of some "backyard mechanic" that just guesses or jimmy-rigs it to make it work LOL.

Thank you.
Mandy Gardin Chehalis, WA

Hi Mandy,

Before we get going on your question, let me set the record straight on backyard mechanics. There are good ones, bad ones and really bad ones. Make sure you work with a good one.

In my humble backyard mechanic opinion, to run 39s youíre looking at somewhere in the 8-inch suspension lift range. That should give you adequate room for that big of a tire. If youíre open to cutting or hammering metal, then 6-inch will work.

Good luck!

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MUD SNORTINí CHEVY Z71

4x4 AnswerMan,

I have a 2001 Chevy Z71 truck with the 5.3. Iím looking to put a snorkel on my truck to keep from getting so much mud and water into my intake. I havenít found anyone that makes a snorkel for this truck!!! Any help would me much appreciated

Jacob

Hi Jacob,

Safari Snorkel is pretty much the only company that makes bolt-on applications, besides Volant. Unfortunately neither company makes one for your truck. What you may need to do is use existing parts from another kit and customize it for your truck. Some guys have had luck using the Toyota FJ80 model on Chevy Trucks. Here is a thread on one
http://coloradok5.com/forums/showthread.php?t=174617 

Make sure to also check out two DIY Snorkel articles here on Off-Road.com

D-I-Y Custom Snorkel


Build your own off-road snorkel


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1971 CHEVY K20 RESTO

Hello 4x4 AnswerMan,

I am soon going to begin restoring my pickup and there is one issue that I need to resolve before I start.   I bought the truck without an engine but the 4 speed transmission was/is there.  My wife is not used to driving a standard transmission and this was somewhat of a dilemma for me until I thought "well why not just put in an automatic instead when I go to purchase an engine?".  I am going to keep the original size engine 350ci so I believe that a turbo hydromatic 400 is the trans that would go with this.  Surely there had to have been trucks of this year built with automatics in them?  Wasn't there?   Is this transmission the correct one to install?  Can it be installed without too many modifications to the frame, driveline, etc?  (I am going to do all the mechanical work myself).  Does or should the transmission be upgraded or rebuilt to be able to handle the greater torque it may have to endure with the truck being a 4X4?     If you can provide me with an answer to these questions I would greatly be indebted to you - I know of nowhere else to go in order to find out the answer to these questions. If you have the time can you please list the types of things that I will have to change in order to do this - that is - IF I can do this.  If you are not able to assist me can you direct me to someone or somewhere where I can find out this information?   Thank you very much for your time and your help.   Respectfully,   Guy Morin Alberta, Canada 

Fine example of restored 1971 Chevy K20 4x4 Pick-up Truck 

Hi Guy,

Glad to hear youíre working on old iron. We like seeing these classic trucks on and off-road. As for your dilemma, youíre on the right track--the Turbo 400 is a great choice for an automatic. In fact, it can be found on many 3/4 and 1-ton GM trucks from that era.

Itís plenty strong, but if you want to soup-up, you can certainly take it to a local transmission shop and have them go through it. They can make recommendations on what modification can be made, depending on the horsepower and use. Just make sure you find a 4WD model TH400. The 2WD is different.

As for transfer case, the NP205 is the clear choice. This transfer case was mated to the TH400 from the factory, and it is rock solid. 

You can find an NP205 that fits 1971-1985 GM trucks. You may even be able to use a cross member from a donor truck to mount if yours doesnít have it.

The ideal scenario would be to find a donor GM 3/4 or 1-ton truck 1971 - 1985 to get the whole package from. Transmission and transfer case combo already bolted together. You may also need other mounts, bell housing, cables and such.

Search your local auto dismantlers, eBay and Craigslist. Get back to us with an update.

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PROPELLER SHAFT PLEASE

4x4 AnswerMan,

Is it possible for me to get a propeller shaft rear for my Ford F350 1997 model. I have manual V8 7.5 engine. Thanks for your kind help and time.
Malik

Hi Malik,

Sure you can get a propeller shaft for your Ford F350. The man to talk to is Tom Woods. He can build any custom properller shaft, or as we call them here in the US, drive shaft. Tom Woods uses quality components and the workmanship is top notch. 

You can contact Tom Woods Custom Drive Shafts at http://www.4xshaft.com/ or 877-497-4238.

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SLIPINí T-CASE

4x4 AnserMan,

My 94 Blazer has recently started jumping out of gear when I hit any kind of bump on the road. Usually only when under torque. If I remove my foot from the gas pedal before the bump, Iím usually OK. Nothing underneath the truck is visibly broken. Help!

Brad
Nashville, TN

Hi Brad,
I believe youíre experiencing transfer case jump. This does happen sometimes, especially in 4LO. It can be that youíre not fully engaged. Try adjusting the linkage from the lever to the transfer case that runs under the truck. 

If you have an electronic transfer case, then it can be any of these: 4WD switch, 4WD actuator, transfer case.

Before you go spend a lot of time and money, make sure your transfer case has enough fluid. You can also try servicing it if itís been over 25,000 miles. Change the fluid and see if that helps.

If itís still giving problems, take it to your local transmission shop for a check up.

Good luck

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DODGE RAM WITH CROSSED WIRES?
Fuse Box on 3rd Gen Dodge Ram Pick-up Truck

4x4 AnswerMan,

I have a Dodge Ram 3500 Diesel 6.7, why does the fuse box keep going out?  I have replaced two already.

Felix

Hi Felix,

Modern technology is great until it stops working and you have to figure out what the heck is wrong. On these newer Dodge Ram Trucks, the fuse box you refer to has a computer that monitors each circuit (also known as the PCM). If it notices any drop or erratic draw on voltage, it shuts off that circuit. Sometimes you get lucky and the fuse blows, other times, it just shuts off and the ďCheck EngineĒ light come on. In the latter case, you need to take it to the Dodge dealership, which it seems you have already done. 

They can usually run a diagnostics test to see what is causing it, then re-set and update (re-flash) the computer. From what Iíve gathered, the PCM can only be re-set two times, then you need to replace with new one. They arenít cheap either.

If you tow a trailer, a short circuit in the wiring may be setting it off.  Here is a really good thread on one of our sister sites on how to fix this problem http://www.cumminsforum.com/forum/03-04-general-discussion/394701-hooked-up-trailer-blew-bunch-stuff.html

If itís not a trailer problem, you will need to check all your wiring for damage.  Start with any aftermarket items you might have added that may be drawing more power than your Dodge Ram is programmed to do so--like gauges, lights, switches, etc.

We had a similar problem with our Dodge Mega Cab and found our problem was in one of the instrument cluster plugs jiggling loose. We snapped it back in place and havenít had any more issues. Problem fixed.

Good luck

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K5 DISK BRAKE FINESSE
Off-Road Designs Rear Disk Conversion on GM 14-bolt

Howdy 4x4 AnswerMan,

Iíve got an Ď85 K5 with a 14-bolt corporate GM rear axle. Iím attempting a disc brake conversion. The pads seem to be dragging a lot. I installed a proportioning valve but, I havenít messed with the Master cylinder or the dual brake circuit pressure differential valve. What would you suggest?

Thanks a lot.  

Steve Sheffield


Hi Steve,

A very nice upgrade. If youíve already gone through the trouble of doing a rear disk brake conversion, proportioning valve, and are still experiencing problems--make sure the proportioning valve is adjusted correctly. You want 90% of power up front, 10% in the rear. Fine-tune to your needs/liking.

Another item to make sure is in good running order is your brake booster and master cylinder.

If you are still stuck, give the guys at Off-Road Designs a call. They are very familiar with this upgrade and what it takes to make it work just right.

More info at http://offroaddesign.com/ or (970) 945-7777

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1, 2, 3-LINK
4x4 AnswerMan,
Is there somewhere I can get info on installing a three link on a 1979 Bronco. I'm putting a Dana 60 under the front. I have the kit. Just not sure exactly where to mount everything. Any help would be great.
Thanks,
Alex
Hi Alex,

Best place to get information on your specific 3-link kit would be directly from the manufacturer or fabricator that made it.  If you are building a custom set-up, then you should definitely check out our Off-Road.com forums Ford Section and get a thread going:

Ford 67-96 F-Series, 78-96 Bronco
http://forums.off-road.com/ford-67-96-f-series-78-96-bronco/

If youíre planning on retaining the factory control arms, and are more concerned on how to swap in the Dana 60, here is a article we found that may give you some insight on what all is involved

RC Dana 60 Coil-Sprung Front Axle Conversion
http://www.projectbronco.com/Technical_Articles/RCdana_60_conversion.htm

If you still canít find the information you need, try our friends at Pirate4x4.com.

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.

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