DANA 80, overhaul

['956Wheel]

Mines a '95 3500 2 WD with a 3:54 Dana 80. We do some towing with it and I like to keep things in top shape. I have noticed a "clunck" in the drivetrain when putting in the clutch before stopping, all U-joints have been changed but the noise persists when "unloading" the drivetrain.



Looking at the book I find that ring and pinion is allowed . 008 lash, I find more than that, I have not put an indicator on it to see exactly how much lash is present but it is more than . 008.



Anybody out there rebuild the Dana 80? If so I would like to hear how it went, special tools (if any) needed, as well as things to look for.



Mike

 

[B.G. Smith]

Clunk

I doubt that the noise that you are hearing is the differential. Have you checked the slack in the splines on the front and middle "U" joints? Try jacking up one rear wheel and rotate the tire back and forth by hand ( assuming you don't have limited slip diff. ) and see if you can duplicate the noise. bg

 

['956Wheel]

it is LSD

B. G. The diff is limited slip and all U-Joints have been changed (3).

The splined section of the driveshaft was inspected when I changed out the joints... no slack. Also the noise is loucer when the driveline is warmed up.



Mike

 

[Joseph Donnelly]

See my discussion in TDR#24. Dana went to very little preload on the carrier bearings. After break-in, you may bend up with no preload or worse, slack. That can translate into more than 0. 008" backlash. For heat minimization, 0. 006-0. 008" is probably good.

 

[Extreme1]

Do what Joe says, I just installed a LSD in my driveway. You would need a bearing puller for the carrier and probably for the pinion as well. Mine had 231,000 miles on it and had . 010 backlash. Pattern/gears looked OK. You could check the bearings like Joe describes in the article, check the backlash and then decide what you want to do.