1998.5-2002 Dodge 5.9L Cummins Differential Parts

Differentials on the 1998.5-2002 Ram 5.9L Cummins

Three Dana axles cover every Cummins truck of this generation. The Dana 60 front on four-wheel-drive trucks has a 9.75 in ring gear. The Dana 70 rear, with a 10.5 in ring gear, sits under 2500s with the automatic, and Power-Lok or Trac-Loc limited slips were options on it. The Dana 80 is a full-floating rear with an 11.25 in ring gear; it's the only rear axle used on these 3500s and the one fitted to manual-transmission 2500s, and from 1998 its limited slip is a four-pinion Trac-Lok. Factory ratios were 3.54/3.55 for most trucks and 4.10 for heavy towing.

What to check before you pull a cover

Read the axle tag first. Ordering by model alone isn't enough, because the same 2500 can have a Dana 70 or a Dana 80 depending on its transmission. Next, find out whether your axle has a limited slip; if it does, the owner's manual calls for limited-slip additive with the gear oil. On the Dana 60 front you can seal the cover with RTV or use a dedicated cover gasket. On the Dana 80, the service guide calls for the cover bolts at 30 lb-ft in an alternating pattern and gives RTV 24 hours to cure.

Stock cover or finned aluminum?

If the truck isn't working hard, a stock cover with fresh fluid and a good seal does the job. If you tow, a finned aluminum cover is worth a look: Mag-Hytec builds them for the Dana 60, 70 and 80 with added capacity, a dipstick and a drain plug. For fluid, 80W-90 is Dodge's base spec on the Dana 80, and 75W-140 synthetic is the heavier choice Diesel Hub's schedule calls for in all of these axles.

What we carry

Covers come from Mag-Hytec (Dana 60 front in standard and vented versions, plus Dana 70 and Dana 80 rears), BD Diesel (a Dana 70 rear) and AFE (Street Series and Dana 80 rears). MAHLE supplies cover gaskets, and ATS Diesel Performance has a drain plug for ATS pans and covers. Gear oil comes from Hot Shot's Secret (ADRENALINE and Blue Diamond), Lucas Oil (synthetic and heavy-duty grades) and Royal Purple (Max-Gear 75W-140). For the rest of the truck, start at our Cummins hub.

Fitment notes

Front covers only apply to 4x4 trucks. Rear covers and gaskets are axle-specific, so the axle tag beats the window sticker. Some products here list wider year ranges or other trucks in their titles, such as Ford Power Stroke fitment on a Dana 80 cover; what matters is that the axle matches. Verify by VIN when in doubt.

Frequently asked questions

Does a 2500 use the same rear cover as a 3500?

Only if the 2500 has a manual transmission. Every 3500 of this generation has a Dana 80, and manual 2500s share it. Automatic 2500s have a Dana 70 and need a Dana 70 cover. The axle tag settles it.

Do I need limited-slip additive?

If your axle has a limited slip, follow the owner's manual and use it. The Dana 80 used a Trac-Lok limited slip from 1998, and the Dana 70 offered Power-Lok or Trac-Loc, so check what's in yours. Then check the product page to see whether a gear oil is rated for limited-slip use.

Gasket or RTV on the front Dana 60?

Either works on the Dana 60 front cover, so it comes down to preference. The MAHLE gaskets here are listed by model year, so open each product page to confirm which axle it fits before you order.

Not sure what fits? Call the shop at the number in the header, or use the fitment checker on any product page. We install everything we sell.