Hey Guys, New weird problem. Its a 2001 3500 auto trans 5.9l 85,000 miles.

The issue is when I make a very hard turn, both right or left, the rear end (or something in the back) seems to be extremely loose and starts to bounce and make an extremely loud banging noise that goes away after I slow down and straighten out. It really feels like the entire truck is going to rattle apart until I get it straight again. Any ideas would be greatly appreciated.

Thanks Neal

I would guess you need to change the oil. The clutches are probably grabbing and causing the ruckus. If the oil don't have the modifier included you will need to buy the bottle and add it. Depending on the size of the bottle it might need 2 of them.

I would agree with the above unless you have an open diff. Sounds like you dont.

Just got out from under the truck and found this info:

It looks like it is a DANA 80 42434 272 0 REV AB Does that sound like the type with clutches?

Again thanks a million, Neal

Its odd that it would make that much noise from needing to change the oil considering the truck only has 80k

Though it is old and could have cantaminates 

5 hours ago, Rotket said:

Its odd that it would make that much noise from needing to change the oil considering the truck only has 80k

Though it is old and could have cantaminates 

19 year old fluid, look at it that way. may need a change and additive

Differential fluid (open or limited slip) should be changed every 30k miles or once every 3 years.

The tag inside of the glove box should say DSA if you have the anti-slip or whatever they call it. 

DRL is the dana 80 (which you should have)

DMD or DMF  is 3.54 or 4.11 ratio (you have one or the other)

WLA is dual rear wheels (which you should also have)  

 

If you do not have DSA on that tag, your truck was not originally equipped, but someone could have swapped rear ends.

 

My brother's truck with just a tick over 100k miles needed carrier bearings.  never jumpy or poppy like you are saying, just noisy.

 

I like the idea of just change the fluid.  put anti-friction additive in.  It will not hurt an open differential, and helps a posi.   (some axle fluids come with the additive already in it,  because it doesn't hurt an open diff.)

 

HTH

Hag

So I do have a Dana M80 DSA Anti-Spin Differential and I got the lube today and am going to change it in the morning.

I'm hoping to check back in tomorrow with the results.

Thanks a million!

BTW- where are the carrier bearings?

13 minutes ago, Neal Gass said:

BTW- where are the carrier bearings

About halfway between the tranny and the rear end. It is in a bracket that is bolted to the frame. It is just one bearing supporting the 2 piece drive shaft. That is the OE set up anyway.

Dripley is mentioning the "carrier bearing" that is part of our 2 piece drive shaft.

 

The "carrier bearings" that I replaced in my brother's truck are the bearings that support the Ring gear carrier (center section) of the rear differential.  (sorry I was not more specific) 

 

When you have your cover off to change the fluid, spend a minute looking closely at the gears inside, and pry the carrier, it should not move left to right or up and down at all.

 

I hope you are just having trouble with the clutches sticking.  That is the most simple explanation

 

 

GL HTH
Hag

Edited July 22, 20204 yr by Haggar

Drained the old fluid and removed the rear differential cover and was surprised at a few things. The old fluid was surprisingly clean and relatively clear. It also didn't have the horrible smell I usually get from gear oils.The lower inside area of the case had no debris or metal shavings and the magnetic fill plug was clean as well, no shavings. Closed it up using a new gasket and refilled it with 75-140w synthetic with friction modifier. Took it out on the road and it seemed worse than ever..............

 

Turned it right around and climbed under in the Nevada 113º in the shade and found

 

The darn thing is just bouncing around in the hanger with so much play I'm surprised it just didn't pop through the bed!

So thanks for pointing in the right direction fo plan B which is now to replace the center bearing and wonder if this is something I can do or do I need special tools to do it.

I'm getting so close and if I get this fixed the truck will be perfect (or for a while) again.

Thanks Neal

The bearing is pressed on so I dont know how hard it is to get off. Going to do mine one day since it is all the OE bearing and u joints. 

Glad you found it! 

Much easier to repair than the differential!

 

Hag

If the bearing won't tap off then slit it with a slitting disc in a grinder, once you're nearly through use a chisel to finally split it, it will drop off and by not going all the way there is no chance of marking the bearing surface

On 7/22/2020 at 7:32 PM, Neal Gass said:

Drained the old fluid and removed the rear differential cover and was surprised at a few things. The old fluid was surprisingly clean and relatively clear. It also didn't have the horrible smell I usually get from gear oils.The lower inside area of the case had no debris or metal shavings and the magnetic fill plug was clean as well, no shavings. Closed it up using a new gasket and refilled it with 75-140w synthetic with friction modifier. Took it out on the road and it seemed worse than ever..............

 

Turned it right around and climbed under in the Nevada 113º in the shade and found

 

The darn thing is just bouncing around in the hanger with so much play I'm surprised it just didn't pop through the bed!

So thanks for pointing in the right direction fo plan B which is now to replace the center bearing and wonder if this is something I can do or do I need special tools to do it.

I'm getting so close and if I get this fixed the truck will be perfect (or for a while) again.

Thanks Neal

this happened to me long ago, the bearing seized and walked out of the rubber carrier. took a 40 ton press to get the bearing off the shaft....

The bearing was OK but I figured I might as well do it right and replace the whole thing. Ground the bearing and split it with a chisel (not that hard) and slid it off. Had a nice piece of pipe that was exactly the size of the bearing and hammered the new one on. Marked all the pieces before I took off the shafts and replaced them in the same orientation that they came off. 

Thanks again for all the help- the truck is perfect again! Neal