Click for Coverage
  • JP Magazine
  • Dirt Sports + Off-Road
  • 4-Wheel & Off-Road
  • Four Wheeler

March 2010 Techline

Posted in How To: Tech Qa on March 1, 2010 Comment (0)
Share this

Where To Write


Ford Truck Transfer Cases "Pops"
My brother in law owns a 1990 Ford 3/4- ton regular cab 4x4, with a swapped-in 302 engine and five-speed granny-low tranny. Was the 302 an option in 1990? (His engine is a '95.)

On to the important stuff: When in four-wheel drive and under a load, like going up a steep hill, a popping noise comes from the transfer case area. Everything seems to work fine, but the noise is a little disturbing. Any ideas?
Mike from KS

A. The 302 was an optional engine in the F-150 and F-250 that were under a 8,500-GVW rating.

As to the noise, which you describe as coming from the transfer case "area" most likely is a problem with the transfer case itself. This is a chain-drive Borg-Warner 13-56 unit, and my guess is that the chain is worn and has elongated at the spot where the links join. This, for lack of a better word, "stretches" the chain and allows it to jump on the drive sprockets. If it has been going on very long, there also could be damage to the sprockets, and they will be needed to be replaced. These transfer cases also have a bit of wear problem with the oil pump housing, so it might be better to find a replacement, used or rebuilt, other than trying to just change out the chain.

Grand Cherokee Brake-Job Tips
I helped my cousin redo the rear brakes on his Grand Cherokee. No problem. Then later, when we did the front brakes, and installed new rotors and pads, we used a C-clamp to push the pistons back into the caliper. Everything worked fine, except the front pads seem to be riding on the rotors, and the rotors are extremely hot. Is there some trick to the front brakes?
Eason Liley
Via E-mail

A. The caliper's piston has a special seal that is designed so that when brake pressure is released, it will cause the piston to slightly retract. The normal clearance between pad and rotor is very close to start with, so without proper retraction of the piston, the pad would constantly be in contact with the rotor.

So why is the piston not retracting? There are a couple of things that may have caused the problem. When pushing the piston in with a C-clamp, you most likely put the clamp on only one side of the piston and cocked it in the bore, thus damaging the seal. There is a special tool used to press the piston back in, but you can use a C-clamp as long as you also use a flat piece of metal across the face of the piston so the pressure of the C-clamp is in the middle of the piston. This prevents the piston from cocking in the bore. I always also recommend that the bleeder screw is open when you do this. Otherwise you're forcing dirty fluid back through the line, past the combination valve and into the master cylinder. Doesn't take much contaminant in the fluid to cause a problem.

Generally, I also recommend that you purchase what are called "loaded calipers" whenever doing a brake job on a 4x4 vehicle. This gets you new pads and a rebuilt caliper. The brakes on a 4x4 vehicle are exposed to much harsher elements than a normal vehicle, hence more of a chance for early wear.

You also need to look at the sliding surfaces and make sure that the caliper slides properly as the brake is applied. Roughness or nicks on the sliding surfaces will cause brake drag. These sliding surfaces should also be lubricated with the proper high-temperature grease.

Mystery Thunks On Lifted Ram
I own a 1999 Dodge Ram 1500. It has a mild suspension lift and a few bolt-on engine modifications. About a week after the warranty expired, I began to notice a rhythmic thunking noise coming from what appears to be the rear axle area. This noise happens when I decelerate or during "easy" braking. It is sometimes more pronounced than other times, but it always seems to happen. What could be causing this, and should I be concerned? How do I fix it?
Jason Burkleo
Weed, CA

A. To me, when you say "rhythmic thunking," it means to me that the noise is continuous and not just a single "thunk." A single thunk could be slack being taken up in a worn U-joint, or even the driveshaft slip yoke binding and then releasing. Well, the U-joint could be really bad, but you would also get the noise when you move away from a stop and normally a bad vibration.

Being rhythmic means that some rotational force is causing the noise. I would think that if it was a problem within the rearend, then the noise would be there all the time. Keep in mind that when you brake or decelerate, the front of the truck drops and the rear slightly rises. Could it be that an e-brake cable, or perhaps part of the exhaust system, is moving and making contact with the driveshaft? That would be the first place that I would start looking.

My next step would be to put the rear axle of the truck on a pair of very secure jackstands so that the tires are off the ground. Block the front wheels both to the front and the back. Have someone sit in the truck and start it up, put it in gear and let the rear wheels turn say, to a point where the speedometer indicates 20 or so mph. Then easily apply the brakes. Now you can carefully listen and try to pinpoint the noise. Even better would be to put it on shop lift where you had better access, being very careful while doing this around rotating parts. Hopefully, you could then pinpoint where the noise was coming from, which would lead you to what was in need of repair.

How Big A Tire For Stock TJ Axles?
I have a 2003 Jeep Wrangler Sport. I want to install a 2-inch budget lift and 33s. My Jeep is primarily a daily driver that gets to see mild off-roading and mud on the weekends. In order to keep drivability, and to make sure that I still have some decent gas mileage, I understand that I need to change the axle gears. So what gearing should I be putting in the front and the back? Since my axles are stock, can I go up to 33s? O is that pretty much guaranteeing me disaster?
Chad Wilson
Wilsey, Kansas

A. For what you're going to use the Jeep for, you can most likely get away with the 33-inch tires, at least for awhile. I am pretty sure your rearend is a Dana Model 35, which is pretty notorious for being, well, a weak link. The differential cover has a rounded shape, somewhat like someone squished a circle a bit, while the much more desirable Dana 44 has an unequal shape with peaks at the top and bottom. I have known people to put over 100,000 miles on their Dana 35s without a problem, and others break the axle or bend the housing with 31-inch tires within 10,000 miles.

There are upgrade kits available from several of our advertisers that use a larger-diameter axleshaft that must be used with either an ARB Air Locker or a Detroit Locker. It's not exactly cheap, at about $1,000, but it's less expensive than a complete rearend swap to a Dana 44 or Ford 8.8. I would also recommend a swap to about 4.11:1 gears to put the rpm range back to where it was before the larger tire swap. The gears will cost you about $200 a set plus the installation. Plan on spending another $1,000 or so for making the gear swap.

Yes, you're going to lose some fuel mileage. The reason is due to the added rolling resistance of the large tires, and to a height increase, exposing more of the underside of the vehicle to "dirty air."

Wants Granny-Low 4-Speed For K-10
I own a 1977 Chevy K-10 with a 400ci V-8, TH350 trans, 4.10:1 axles and 39.5-inch tires. I want to swap out the transmission for a four-speed with a granny-low gear. I have the chance to buy a donor truck that's the same body style with the four-speed, but it has a 350 small-block.

Is this a bad idea or not? What about wheeling with the granny low, or staying away from a certain model tranny? How hard would it be to do the swap? I know I would probably have to buy a new flywheel and clutch.
Brett Applegate

A. Well, you're wise in coming up with a complete truck to make the transmission swap, as there are lots of parts that you will be needing from it.

To start out with, the 400 engine, I don't believe, ever came with the four-speed manual transmission. All of them, to my knowledge, used the automatic and the NP203 full-time transfer case. The only four-speed offered was the SM 465 with gear ratios of 6.55:1, 3.58:1, 1.70:1 and 1.00:1. The transfer case was a part time NP205, which is the preferred transfer case.

You're lucky the donor truck you found was in the same year group as your truck, as there was a spline count and pattern change in the later years.

Now as to the swap, the 400 small-block is an externally balanced engine, so you're going to have to find a manual-trans/TH400 flywheel or have the 350 flywheel balanced to the 400's specifications. Naturally, you're also going to have to use the clutch linkage from the donor truck, as well as the crossmember, driveshafts, and transfer-case shift linkage.

While you're at it, you'll want to take the locking hubs off the donor truck's front axle and install them on your present axles. This way, you can eliminate some parasitic drag of the rotating components when in two-wheel drive and even pick up a mile (or so) per gallon increase in fuel economy.

Tech Letter Of The Month
Best Winch For Prospecting?
I need a winch for those one or two times a year that I manage to get stuck (I'm an amateur gold prospector).

What is the difference between the "less expensive" and "premium" winches? Do I have to spring for a "premium" unit to be confident it will work when I need it?

What are the weak elements (what fails) in the "less expensive" winches?

Poor metallurgy (rusts easily or actually breaks)? The motor overheats and fails?

Poor wire quality (control wire overheats and melts)? Relays overheat and fuse, causing failure? Solenoids short out? All of the above?

Do any of the "less expensive" winches have durable motors?

Can I take a "less expensive" winch and inexpensively address the weak points? For instance, coating with CorrosionX to deal with corrosion, or upgrade solenoids and relays to quality parts

Besides Warn, what are the "quality" reliable winches?

Can you recommend a "less expensive" product that's worth working on?
Mickey Miller
Livermore, CA

A. You brought up a lot of good questions as to winches, as well as an important statement: "I need a winch for those one or two times a year when I manage to get stuck." In reality, most of us only use our winches once or twice a year. In fact, I luckily have not had to use mine in the last two years. However, it's not something that I plan to get rid of just because I have not used it. That would be like saying, "I have not had a need for seat belts in the last two years, so I might as well not use them."

My wife and I run a lot of trails by ourselves, and more than a few times have got into situations where the winch has saved us from a long walk out, and in a couple of cases perhaps saved us from serious injury or death. There have been a few times where we had to use every bit of cable and make numerous pulls to extract ourselves, and put a towel over the winch motor and pour water on it to keep it cool. But most of the winch pulls are just a few feet in length. My 8,000-pound Warn winch is well over 20 years old now, and the only failure has been one solenoid. The cable has been replaced a couple of times, and the drum's side flanges had to be straightened (from pulling from one side and letting the cable stack up against it).

Would one of the "less expensive winches" hold up this long? I don't know, and probably no one else does either, as only time will tell. Your questions are hard to answer because the only experience I have had, and the people that I four-wheel with, all use one of the big three in winches: Warn, Ramsey and Superwinch. Each of these have their own benefits as well as weaknesses.

Do you have a back-up method of extraction if the winch fails, such as a Hi-Lift jack or another vehicle along with you?

Now don't get me wrong. I am not saying that one of the other winches is not capable of working hard and not failing but-and it is a big but-you have to remember that you generally get what you pay for. For instance, Warn's wire rope meets the same standards as those applied to the aircraft industry. Is this true with the less expensive winches? The parts situation can always be a problem on those units acquired overseas. (As an example, on the other hand, I have an imported lathe, mill, sheetmetal brake, and several grinders that have held up quite well and do the job that's intended of them. I did break a part on the lathe, and it took nearly six months to get a replacement. I would not want to use them for producing a product day in and day out.) So the bottom line is that yes, maybe one of the less expensive winches may just be fine for an occasional use. Only you can make that decision. As to recommending one of the "other winches," I don't have clue.



Connect With Us

Newsletter Sign Up

Subscribe to the Magazine

Sponsored Links