Due to my recent purchase of a 1350 yolk Moser 12-bolt I've come accross part numbers for 1310/1350 combo u-joints. Seeing how NAPA's relabeled their famous "447" I thought I'd pass on the info and other part number for the same product:

The new NAPA part number: 240-0447

Spicer: 5-460X
Rockford (RDL): K460
Precision: 348
Neapco: 3-3140

The new NAPA unit cost me $26.21, was stocked on hand (not a rare special order item), and is a greese-able unit that comes with a zerk fitting (screws into the cross body, not at the cap end like some smaller u-joints). I'm not sure who makes the NAPA unit, but all four caps are engraved/stamped with "Made in the USA" on them and the bill lists the "Line" as the NUJ (Napa U Joint I assume).

If you can't find the NAPA part, many off-road guys (who go through u-joints like we do brake pads) find the Spicer brands to be the most durable without going to $100+ units specificly made for axle shafts.

No super-duty style U-joints exist in the 1310/1350 combo spec, although there are several performance units available in 1310, 1330, and of course 1350 sizing. BTW, the 1350 is sometimes referred to just as the "Dana 60" U-joint or "steel cross"... while the 1310 is sometimes called the Dana 44 u-joint (both due to them being used on front axle shafts with that sized differential).

Hope this saves someone time on their upgrades. Just remember though, the 1310/1350 combo joint is fine to get everything up and running (it obviously isn't any weaker than the stock 1310 unit), but to really take advantage of the 1350 yolk you should swap out the driveshaft to a heavy-duty unit with full 1350 yolks.

 

Good info, thanks.

By "super duty" you mean no zerk fittings, correct?

Mike

 

Well... yes... and no. It seems there are "life time guarnateed" u-joints out there that are designed with needle bearings and zerk fittings like the Tom Wood's Gold Seal untis. These sell for ~$35 to $40 a shot, and come in 1310, 1330 , and 1350 sizes. The 1310 have a zerk fitting on one end cap, while the larger 1330 and 1350 units have a center-mounted fitting. Although they're still greeseable units, they're supposedly "high performance" u-joints.

That said, the next step up from a premium greeseable unit seems to be solid-body U-joints. These are included in most performance driveshafts (like the Dynotech unit in my car, and the Denny's Driveshaft stuff as well) as are beefier due to the lack of oil passages (more material) and the stress risers associated with the drilled passages/edges. solid-body joints are highly reccomended by T56 tranny rebuilders so I imagine they're more durable.

The next step up is going to the "extreme duty" solid-body units that are designed to take a beeting. These run about $150 to $250 EACH.

CTM Racing is the most popular of these. They make a Dana 60 unit (1350) and a Dana 44/30 unit (1310). The joints are made of forged 300M steel, which is basically a specially heat-treated form of 4340 steel (which is a bit stronger than 4130 steel) commonly known as "chromoly". Beyond ellimination of the greece passages, these units also elliminate the use of needle-bearings and instead use brass-bushing caps instead. If you checkout the review at www.pirate4x4.com you'll be floored by the abuse these joints can handle. I sent mail to them asking if the Dana 60 units would be usable for a daily driver driveshaft that could see 160+ mph in 4.11 gearing... obviously much different than an 5 mph rock-crawling event where hard impacts will rip u-joints in half on heavy impacts. Last I heard the CTM units were also being cryo-treated after near-net forgeding the 300M and CNC machining to shape.

OX Brand also makes a extreme duty unit that goes for ~$150. This is a newer player to the u-joint field, but I'm told they're pretty slick units. The entire deisgn of the caps/body is different and almost looks space-age in comparison to the massive chunks CTM joints resemble. There is a HOLLOW center section/body and the caps are actually full-sized arms with "anchors" that stick into the body of the joint. After the arms are inserted, they are secured from the top of the body through a removeable cover. Once the u-joint is set up the cover is replaced and the u-joint gets it's strength from the massive arms and wide body shell. OX Brand has plans on releasing a needle-bearing version which "should live twice as long a the bushed version with only a 10% decrease in strength". They claim twice the load capability as the "next nearest competator" (I assume they mean CTM). The arms on the OX Brand unit supposedly can handle ~22,000 psi while the Spicer Dana 60 unit can handle ~5400psi in comparison (this is the upgraded Spicer unit, the older Spicer unit could only handle ~4800psi and that was considered the industry's very best premium u-joint).

Who would've thought there was so much to a simple u-joint?


BTW, OX Brand doesn't reccomend their "front axle shaft u-joint" for driveshaft use. Why? I have no idea... neither did the OX Brand employee who answered the phone, just repeated that they "don't make drive-shaft u-joints". Still waiting for CTM's reply on this issue, but I honestly can't find any details online regarding axle shaft vs driveshaft differences other than the fact that front axle shafts rarely get locked anyway so the u-joint is just coasting along most of the time. Maybe the ellimination of needle bearings makes the life span too short to validate their use on a driveshaft (which is constantly under load)... especially in a daily driver. Maybe CTM can shed some light on the differences between a 1350 Driveshaft unit vs. a 1350 axle shaft. (It can't be the ellimination of a greese fitting that does it... we don't have greese fittings on any driveshafts... it's gotta be the needle bearings or something to do with the yolk design....

 

Cool.

The only reason I knew about the 'no zerk' u-joints if from my friend. He owns a C4 and upgraded the half-shafts to the 'no zerk' joints. He was showing me the difference with the machining of the bearing surfaces. Apparently they fillet the radius' similar to a crank journal fillet to prevent stress risers etc.. If you look at 99% of the u-joints on the market, they have straight 90deg cuts on the bearing surfaces where they transition to the body.

Mike

 

Good point. As with crank journals or after axle splines, the quality peices will fillet the edge to reduce stress risers.

The NAPA 240-0447 has fillet arms (I just pulled the caps to check). Obvioiusly this isn't a super-strong unit as the smaller 1310 arms have 17.8 mm outer diameters and a 4.8mm (3/16") hole in the middle for the greese units. Elliminating the greese passage theoretically only increases the torsional load of the arms by 1%... but from a stress-riser view there's obviously more strength to be gained with less machining, and the sheer capabilities benfit from 8% more cross-section. Solid seems to be the way to go if you can find one, although for combo u-joints like this one it's not an option I've been able to locate.

Material upgrades to 4340 (or 300M) would go a long way, as would near-net forging and cyro-treament like the CTM units. Still waiting to hear back from them regarding the use of their units in a high-speed DS application. Hopefully Tuesday I'll know for sure what's available.

 

On a side note, Moroso has an interesting product for driveshaft u-joints. Normally a driveshaft contains the u-joint in a full-yolk, and the pinion yolk uses a cap/bolt design to pinch the u-joint to the pinion yolk.

The "cap" in stock configurations is more of a simple "strap" with two bolts to hold it on. Upgraded versions use slightly larger caps with a u-bolt to hold the cap over the u-joint's cap.

Moroso has taken this idea one step further apparently. They have created "u-joint girdles" that use billet 7000-series aluminum caps that increase the width of the cap so much that it "spills" out and over the end of the u-joint cap. The idea is that the more support/surface area you can supply the u-joint caps with this girdle, the more force will be transferred correectly to the yolk (with less chance of sheering from off-axis side loading).

I honesly don't know if these girdles really work any better than the aftermarket caps that come with a 1350 yolk, but they've got to be better than any "strap" design if you have a OEM 12-bolt. The reading I've done seems to suggest that this is pointless for a 1310 application (as a 1350 upgrade is much stronger), but for a 1350 application it may be that 1 more step you can take to reinforce your yolk.

Sold as a pair (2 caps, 4 bolts, 4 nuts/washers) Summit Racing sells the 1350 kit (p/n 85830) for $31.39. Seems like cheap insurance in the big picture.

 

I still have the 10 bolt rear. Because of my stall & shift kit, can I upgrade my u-joints to something stronger? What #