On the DS Ram 1500 this is one of the friendlier charging-system jobs, at least with the 5.7 Hemi or early 4.7 V8. The alternator sits high on the passenger side front of the engine, you release the automatic belt tensioner with a breaker bar, pull two 15 mm bolts and a 13 mm battery-cable nut, and the unit lifts straight out. Budget an hour the first time.
The 3.6 Pentastar and the 3.0 EcoDiesel are a different story: the alternator is much lower, the belt tensioner has little swing room, and you will want the truck on stands with the lower splash shield off. The mistake people make most often is over-tightening the B+ output stud nut - it only needs about 10 ft-lb, and cranking it down snaps the stud out of a brand-new alternator. The second most common mistake is replacing a good alternator when the real fault is a corroded battery cable, a bad engine-to-body ground, or the TIPM.
| Item | Type | |
|---|---|---|
| Socket set, metric 3/8 in drive, 8-19 mm shallow and deep Covers battery, mounting, bracket and terminal fasteners. | Required | shop |
| Ratchet 3/8 in drive with 3, 6 and 12 in extensions Reaching the lower mounting bolt and tensioner from above or below. | Required | shop |
| Socket 10 mm, 3/8 in drive Battery negative terminal clamp bolt and small brackets. | Required | shop |
| Socket / wrench 13 mm, 3/8 in drive (some trucks 10 mm) Removes the nut on the alternator B+ output stud. | Required | shop |
| Socket 15 mm 6-point, 3/8 in drive Alternator mounting bolts and the belt tensioner pulley bolt head. | Required | shop |
| Breaker bar 1/2 in drive, 18-24 in, or serpentine belt tool Swings the automatic belt tensioner to release the belt. | Required | shop |
| Serpentine belt tool kit Low-profile belt tool with 15 mm crowfoot / socket set Needed on 3.6 Pentastar and EcoDiesel where there is no room for a breaker bar. | Recommended | shop |
| Torque wrench 3/8 in drive, 10-80 ft-lb Sets mounting bolts and the B+ nut correctly in aluminum brackets. | Required | shop |
| Swivel / wobble extension 3/8 in drive wobble set Angled access to the rear alternator bolt behind the belt. | Recommended | shop |
| Trim / pry tool set Plastic Releases the push-tab field connector without breaking it. | Recommended | shop |
| Jack and jack stands 2.5 ton minimum 3.6 Pentastar and EcoDiesel alternators are reached from below. | Required | shop |
| 7 mm socket or flat screwdriver 7 mm for hose-clamp style screws Moving coolant hoses or air box tubing out of the way. | Recommended | shop |
| Multimeter DC volts, 20 V range Confirms the old unit is bad and verifies 13.5-14.7 V after install. | Recommended | shop |
| Alternator 160 A or 220 A depending on engine/trim; EcoDiesel may have dual The replacement unit; match amperage and connector. | Parts | shop |
| Serpentine belt Engine-specific, check length Replace while it is off if it is glazed or cracked. | Parts | shop |
| Battery terminal / contact cleaner Electrical contact cleaner Cleans the B+ stud and ring terminal for a low-resistance connection. | Consumables | shop |
| Dielectric grease Small tube Protects the field connector and B+ terminal from corrosion. | Consumables | shop |
| Safety glasses Debris falls from the engine bay while working overhead. | Safety | shop |
| Mechanic's gloves Tight metal edges around the alternator bracket. | Safety | shop |
5.7 Hemi and 4.7 V8: alternator high on the passenger side, two M10 bolts, 15 mm, all accessible from above; tensioner takes a 15 mm socket or 1/2 in breaker bar. 3.6 Pentastar: three 15 mm bolts, alternator lower on the engine, removed downward, and the tight tensioner usually needs a dedicated low-profile serpentine belt tool. 3.0 EcoDiesel: 13 mm and 15 mm fasteners, lowest and hardest access, lower splash shield must come off, and some trucks are fitted with a second alternator.
| Alternator mounting bolts (M10, 5.7 Hemi / 4.7 V8) | 40 ft-lb (54 Nm) - verify in the service manual |
| Alternator mounting bolts (3.6 Pentastar) | verify in the service manual |
| B+ output stud nut | about 10 ft-lb (13 Nm) - verify in the service manual |
| Belt tensioner assembly bolt (if removed) | verify in the service manual |
| Battery negative terminal clamp | about 5 ft-lb (7 Nm) |
The 15 mm mounting bolts and 13 mm B+ nut cover the vast majority of DS Ram 1500s, but stud nut size varies between 10 mm and 13 mm by alternator supplier and torque figures should be confirmed against a FSM or AllData entry for your exact year and engine.
No flash programming is required for a like-for-like alternator. Disconnecting the battery clears the PCM's battery-state learn, and a 15-20 minute drive lets it recalibrate charging output; if you install a different amperage rating than the factory unit a shop scan tool can be used to confirm configuration.
Front passenger side of the engine, mounted high on the accessory bracket above the A/C compressor. You can see it as soon as you open the hood and it comes out from above with a 15 mm socket and a 3/8 in ratchet.
No. The belt runs over the alternator pulley, so you must unload the automatic tensioner and slip the belt off. Take a photo of the routing first, or use the diagram on the fan shroud.
With the engine running, battery voltage should read 13.5-14.7 V; under 13 V with the engine at idle points to charging failure. Before buying an alternator, load test the battery, inspect the B+ cable end and engine ground strap for corrosion, and check for TIPM-related charging codes, which are common on this generation.