Talking with my Son this morning, He told me his 99 has began making a "poping" sound when he accelerates while turning.I thought I would try to get some preinspection info, or advice before we drop the cover off this afternoon.He changed the pinion seal and gear oil last summer with some Oreilly brand synthetic, and not being there I`m not sure if its a limited slip or not??I know GM vehicles have required what everyone called a "fish oil" additive for clutch pack diffs.I`m hoping this is the best case scenario.

First find out if it is a limited slip and go from there. Jack the axle off the ground in neutral when rolling one wheel they should both rotate the same direction if a limited slip or in opposite directions if an open diff.

The description he gave you sounds to me alot like when the spider gears go out.Sent from my XT907 using Tapatalk 2

The axle splines wear out after awhile as well. When this happens the axles skips a bit when you turn. This make a loud popping sound. I went through this a few times.

Did`nt get a chance to look at it today he`s been working with another rancher all day.Cajflynn what was the fix in your case? Axles, spider gears? what you said is exactly what he described.I really don`t think its limited slip, but we still need to get a look at it.

I had to get new axles. I also replaced the spider gears, bearings, and races. In hindsight it would have been cheaper and easier to buy a complete rear end.

Drop the cover and look for metal. But, it sounds like the oil may be worn out. Could only need oil change. Some 4WD use really works the limited slip clutches and oil.

well, we dropped the cover off this evening and the spider gears, and pins are all extremely loose. The gear to the left axle in particular has at least an 1/8" slop in n out.This is my first trip into a Dana but it looks like pull axles, and drop the third member out to get to the spiders... Ring and pinion look good. If the axles are salvageable it could ease the pain:pray:

I'm with Oldbeek on this, pop the cover off and inspect, look for metal flakes and check for play at axles in the spider gears. It's cheap to inspect, some rtv sealent and 85w-140 gear oil. most of the gear oil I've seen comes with the limited slip additive in it now.

Spider gears are shot.. I need to identify which axle I`m dealing with for parts info.I googled Dana`s home page, and they are a huge Company.Is there a standard axle in 99 or do you need the VIN?

It will have either a Dana 80 or a Dana 70. You should be able to find a build sticker that will tell you what axle you have if I remember correctly it's either on the underside of the hood or in the glove box. Sent from my XT907 using Tapatalk 2

Typically I use 80w-90 gear lube and a tube a silicone for the cover. I'm a open diff so I don't have all the weird problems with fluid additives and such. As for the slop I would look at the gears closely for any damage.

Most all 2500 with automatic are the D70. I was told by a guy that owns a local driveline shop that Dana axles are stamped with an identifying number on the bottom of the axle. If you crawl under the truck, drivers side of pinion on the front side of the axle, look under the reinforcing web between the axle tube and pinion housing. It should either be stamped 70 or 80. There's some other numbers there as well I forget what they are (nothing important) I have only confirmed this with a few trucks so I do not know how common this is

If you have not found what axel is in the truck you should find the info inside the glovebox. Open it and look on the inside of the front cover and you will find the information there.Don

Mine is a dana 70u with the Dana PowerLock and 32 spine axles. The spiders gear were like a $350 set. Then there is the rebuild kit for the bearings, races, shims, etc for another couple hundred. Axles are really expensive as they are not made anymore. These are not the easiest things to rebuild either. A good low mileage junker might be the ticket. You could even upgrade to a Dana 80 that way and get rear disc brakes.

Auto tranny rigs are all D70, and manual tranny rigs are D80.

You were looking for the clunk sound when turning under power. Loose spiders will not make a clunk. I had a business rebuilding dana diffs. How much play is in your pinion if you rotate it back and forth. 1/8th turn would be normal wear of the spiders. 1/4 turn would be excessive. Are you starting a rebuild project for a minor wear problem. You really should have a diff. spreader, depth guage set and special bearing drivers and pullers to do a proper bearing replace job. New limited slip oil and silicon sealer will cure your original problem.

Thanks guys for all the input! He ran the VIN by the local stealership, and it is a D70 with 4:10 gears.

He may have had a stroke of luck today.. A local salvage has a match from a burned out 99 for $500 bucks. They said they would guarantee it and drop the cover off for inspection:hyper:If its good n tight I don`t think he can go wrong with this.

Judging by the shape of the spider gears, the axles are probably not far behind in the present rear end.

I`m thinking we will try to go with Caj`s wisdom on this one:thumbup2:

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You were looking for the clunk sound when turning under power. Loose spiders will not make a clunk. I had a business rebuilding dana diffs. How much play is in your pinion if you rotate it back and forth. 1/8th turn would be normal wear of the spiders. 1/4 turn would be excessive. Are you starting a rebuild project for a minor wear problem. You really should have a diff. spreader, depth guage set and special bearing drivers and pullers to do a proper bearing replace job. New limited slip oil and silicon sealer will cure your original problem.

It was`nt really making a clunk. when I saw it for my self it was a sharp "pop" and you could visibly see the tire shake. The spiders are so bad you can jack it up, turn one tire and the other one does`nt turn at all.

Frankly I am shocked that he has`nt noticed it a long time ago.

If it is the clutch pack binding it will snap violently. I had a sand drag machine that needed diff oil changed every season. Turning one wheel and the other does not turn, the pinion is turning and rig is in neutral.

Typically I use 80w-90 gear lube and a tube a silicone for the cover. I'm a open diff so I don't have all the weird problems with fluid additives and such. As for the slop I would look at the gears closely for any damage.

This new rear end is a limited slip.. I know I have browsed a tread here where the debate was whether "limited Slip" gear oil is sufficient, or an additive still needs to be put in?? I guess we can see as we go? for now he seems to have gotten a hell of a deal.

Put the additive in, Chances are good you will get a hell of a chatter without it. You may not get it right away if the oil previously in it had the additive but as the new oil washes the additive off of the clutch plates you will feel it. And that is not really good for the clutches. Putting the additive in is just cheap insurance, it will not hurt anything by adding it.