2nd Gen Non-Engine/Transmission Dana 80, How many miles??

[johnjackson]

My '98 12-valve has 370k miles on it. I'm hearing a growl at 40-50 mph that sounds like the rear end. I carry tools etc. but don't heavy haul with the truck. Does the rear-end need a complete rebuild at this many miles? Thanks, John

 

[JR]

Mileage is not the sole factor in determining the life expectancy of a component. My last truck had a Dana 80 and went over 400k on the original assembly. It also did a good bit of heavy towing.
Does the noise get worse when under power? Do you hear it while cornering?
I would disconnect the drive shaft and physically inspect/rotate each universal joint and do a careful inspection of the carrier bearing before condemning anything internally.
You could also drop the diff pan and do an inspection if the driveshaft checks out. Catch the oil in something clean so you can inspect it for any metallic flake.

 

[KATOOM]

If the fluid has never been changed then you can only expect something to last as well as its maintained. You'll have to open the cover and see how everything looks and what condition the fluid is.

 

[johnjackson]

I'll check the u-joints but in the past when a u-joint was going I got a vibration at a certain speed. No vibration now. Not throttle sensitive. Maybe a little louder on hard turns at the 40-50 speed where I hear it the loudest. Don't hear much under 30. Over 55mph, engine, tire, wind noise etc. seem to block it out. I'm guessing well over 300hp and I used it quite a bit when I first amped it up. I use Redline synthetic everywhere. In the 370k miles I've probably changed rear-end lube 6 or 8 times(probably not as often as should be changed). Thanks for suggestions. Not looking forward to a total rebuild. John

 

[KATOOM]

It could simply be that the clutches and plates need attention. I've seen pictures of people opening the carrier only to find the clutch packs in a seriously poor condition.

 

[johnjackson]

The clutch packs have been shot for 5 or6 years(no posi at all) since I was sunk to the doors in a Nevada bog for half a day. With enough back and forth finally clawed my way out. No winch and no cell service. But why would worn out clutch packs make a growling noise?

 

[KATOOM]

Because you're hearing metal on metal in the pack and/or some or all are broken. As I mentioned some members have found their clutch pack busted and cracked. Here's a good thread about re-stacking you may like. http://www.cumminsforum.com/forum/98-5-02-powertrain/350031-dana-80-restack-2-a.html

 

[GAmes]

My D80 is the only piece in the powertrain that is original, and the LS still works as well, at least it did a month ago when I was maneuvering a big 5er into a muddy RV park. I've never been stuck in a Nevada bog though.

 

[johnjackson]

GAmes that's impressive millage. No wheel bearing replacement in your D80 or anything? When I noticed my LS wasn't working I filled the diff with the Redline oil that the autocross racers use to tighten up their LS's and I didn't add any friction modifier. That revived it for awhile, but now it works like an open differential. I've also replaced the pinion seal a couple times.

 

[GAmes]

One wheel seal started leaking at about 800k so I replaced them both, along with the original brake shoes since I was in there anyway. Three pinion seals. I've been using Royal Purple, no modifier added since I installed the mag hytec about a million miles ago. I change it every 50k miles which is probably overkill.

 

[fest3er]

297k miles on my '98 2500. The Dana has growled due to a failing bearing since before I moved out of N. Illinois 16 years ago at around 30k miles. The ring gear has some pitting which probably adds to the noise. It has gotten worse over the years. At -20°F, it gets loud. I suspect I might get 1MPG better mileage if I fixed it.

A lot of these Danas are noisy. As I understand, the noise is why Chrysler switched to American Axle.

 

[johnjackson]

Thanks Neal. I'll pull the cover and inspect. Refill with fresh Redline if I don't see anything that looks bad.

 

[GAmes]

297k miles on my '98 2500.

Correct me if I'm wrong, but isn't the D80 in 2500s different than the ones in 3500s? Not just axle length, which might come into play, but ring & pinion as well?

 

[KATOOM]

Correct me if I'm wrong, but isn't the D80 in 2500s different than the ones in 3500s? Not just axle length, which might come into play, but ring & pinion as well?

No. The "hybrid" difference is the spindles to accept the DRW. There has been reference to the SRW version having a different outer or inner spindle bearing (cant remember which one) than whats found on the DRW version. Other than that, they're exactly the same.

 

[SAndreasen]

Manual specifies changing front and rear axle lubricant every 15000 miles on schedule b maintenance

 

[JR]

Thats assuming one runs 80w90. Synthetic 75w90 or 75w140 holds up to the high shear/high temps exponentially better than 80w90.

 

[JMcCoy]

I would also check the drive shaft carrier bearing. If you need, I need a posi unit, I have a Power-Lock with 200,000. It is yours for the price of shipping and a case of beer. It is a 4.10 and up carrier.