Preventative Maintenance for Dodge Second Generation Front Axles

The 4x4 front drive axle and attached components have always required a substantial amount of preventative maintenance to remain in peak operating condition. Periodic front axle maintenance and attention to detail can greatly extend the service life of your Dodge 4x4 and minimize the chances of a catastrophic component failure.

The goal in practicing preventative maintenance (PM) is to achieve maximum safe service life of a vehicle and it s components. With a PM program, service is on a schedule and the predictable costs can be prepared for. Admittedly, there is a significant cost to good maintenance, but in the long run it is far cheaper than having parts fail at the worst possible time.

Individual replacement parts and comprehensive rebuild/renew kits with, and without, special tools are readily available. For lubricants, aftermarket alternatives meeting Mopar specifications are easily found. In our shop, we now use only synthetic greases on chassis components and synthetic gear lubes in most front differentials.


Wheel Bearings

The unitized wheel bearing/hub assembly is not serviceable and must be replaced as an assembly. Compared to first generation trucks, the new hub design offers increased service life, but at a much higher replacement cost. We often work on ranch and contractor trucks with loose or failed front wheel bearings starting around 85, 000 miles. In contrast, bearings in what we call town trucks may last well over 150, 000 miles. Since the bearing and hub is a unitized set, little preventative maintenance can be done except checking for loose wheel bearings at every tire rotation.

Checking for loose wheel bearings on 1997 W3500

Any wheel that is cracked, bent, or has worn lug nut holes should be replaced. Proper tightening of the lug nuts in a criss-cross pattern, with a torque wrench to the specified torque is absolutely critical to the safe operation of your Dodge. Two piece, dual wheel lug nuts should be cleaned and lubricated with two drops of oil at the interface of the hex nut and washer every time the tires are rotated. Wheel nuts should be retorqued to specification after 100 and 500 miles with a torque wrench. Correct lug nut torque specifications are listed in your owners manual. Tire inflation should be checked at least monthly. Tires should be rotated as specified in your owners manual.


Brakes

Conventional single piston floating caliper disc brakes equip Dodge Ram 4x4 trucks. The rotors themselves have a diameter of 12.5 and a nominal thickness of 1.496 . Unlike some comparable year Fords which have much thinner rotors, Dodge trucks rarely experience rotor cracking. However, brake pedal pulsation caused by warped rotors is fairly common. This condition, which is often found on trailer towing units, occurs when hard braking generates excessive heat causing lateral runout to exceed .005 . Accurate machining of the rotors with a hub mounted, on vehicle brake lathe will cure the problem. Used hub and rotor assemblies cannot be reliably and accurately machined on conventional brake lathes due to damage and/or rust in the splined bore (1994-1999) or rotor center (2000-2002).

The only way to accurately machine brake rotors on 1994 and newer trucks is with an on-the-vehicle, hub mounted brake lathe which is capable of refinishing rotors to less then .003" runout.

Brake components should be inspected at every tire rotation. We recommend the caliper pins, caliper pin boot seals, and the contact area between the caliper mount and caliper, be lubricated with synthetic brake caliper lubricant yearly. Any damaged or worn parts should be replaced. Corrosion inside the caliper occurs when brake fluid absorbs water from the atmosphere (the master cylinder is vented) which can lead to the pistons sticking in the bores and poor braking performance. In our shop, we usually replace the caliper assemblies complete with new pins and boots whenever brake pad replacement is required.

Worn and pitted brake caliper anchor pin bushing will adversely effect brake performance

There is no factory recommended brake fluid change interval, but changing the brake fluid with new DOT 3 brake fluid when the calipers are replaced will help remove water and rust from the system and is a good preventative maintenance practice. (Recent test data has shown internal brake system corrosion to be primarily caused by a chemical reaction involving the copper content of brake system components). Brake hoses should be replaced any time the outer covering is damaged or cracked. On trucks with anti-lock brakes (ABS), failure of the mechanical part of the ABS valve is often caused by rust jamming the valve. The wires and sensors on ABS systems are easily damaged and should be replaced anytime damage is found.


Ball Joints and Axle U-Joints

The original equipment ball joints and axle u-joints are non-greaseable and can only be serviced by replacement. Aftermarket greaseable and original equipment replacement ball joints and axle u-joints are both available. Greaseable types should be lubricated at every oil change or after they have been submerged under water. Anytime the outer axle shaft is separated from the hub, the splines should be coated with anti-seize compound or grease before reinstallation.

 

Ball Joint Kit includes parts, chemicals and special tools required to replace your worn out ball joints.
Axle u-joints are available in both greaseable and non-greaseable versions.
Lube axle shaft splines before reinstalling hub assembly.

Vacuum Shift Control System

On second generation trucks through the 2001 model year, the left axle shaft is always turning the small differential gears. The right outer axle can be disconnected from the intermediate shaft by a vacuum controlled shift unit. Loss of vacuum is the most common problem due to hose/connection damage or a defective transfer case mounted control valve. Inspection of the vacuum hoses should be done at every oil change with particular attention to the hoses from the frame to axle. Any damaged hoses should be immediately replaced. Shift motor problems are also common. The motor itself can not be serviced and must be replaced when failure occurs.

 

Differential

Periodic servicing includes pulling the differential cover, cleaning the unit, and refilling with fresh gear lube. When the differential cover is off, backlash between the ring and pinion gears can be checked. Factory backlash specification is .005 -.008 . If backlash exceeds .010 it is probable that the differential and/or pinion bearings are worn to the point of requiring replacement. Also, check the axle vent hose for damage and look for oil leakage down the axle tubes and from the pinion seal every time the engine oil is changed. A plugged vent hose can allow pressure to build up inside the axle and lead to seal failure. Dodge recommends the front axle lubricant be changed at 12, 000 mile intervals on trucks subjected to heavy duty use. For trucks operated under less strenuous conditions, we recommend the fluid be changed every 2 years.

Checking ring gear backlash with a dial indicator before spreading case and removing differential. The QT1032 or 1033 case spreader is used to relieve the .015" preload on differential bearings.


Steering

Greaseable steering linkage components should be lubricated at every oil change. At the same time, check for damaged or loose steering linkage and steering stabilizers. Wander is the most common steering complaint. The main cause is looseness in the left end of tracking arm where it attaches to the frame.