2nd Gen Non-Engine/Transmission The down side of 500+ HP, Dana 80 is in critical condition

[R.ebel]

Hi all, I just thought I'd post my experience here. My Truck has been heavily bombed since the ODO was showing 90K. I'm now at 145K. The Rear differential is not a limited slip type.



My better half got me a Mag-Hytec rear differential cover for Christmas. Oo. So the other day I went to install the new cover, was due to change the Rear axel lube anyway. Have been running Valvoline semi synthetic 75-140. After draining the oil I took a good look at the gears.

The ring and pinion looked good

The spiders looked good

But what's this? chunk of metal . . it appears to be some type of shim material. Long story short is that the driver side carrier bearing spun on the carrier (normally this is a press fit) which allowed the bearing to chew on the shims eventually kicking one completely out and working on the next.



It was a complete coincidence that I dropped the old cover just in time to prevent further damage. I'll be buying a new carrier (upgrading to the Pwr Lok-limited slip) and a master bearing and seal kit. Total damages so far $810. 00 including shipping. I figure another $200 to $300 for the actual overhaul and setting of the preload, back lash etc. Thank God the Ring and Pinion were still in very good shape and will be re-used



FYI: It is reccomended by some shops to refresh the Dana 80 with all new bearings at 125K to prevent this type of failure which is typical of a Dana 80



Also I had not noticed anything abnormal going on with the rear diff. No stange noise or anything else.

 

[mgoncalves]

Glad you caught it before it got real bad.



I remember SledPuller saying that the 70's should be reset at 80k miles and the 80's should be reset at 100k miles. Guess he knew what he was talking about .





Matt

 

[Joseph Donnelly]

I wrote about this problem in TDR#24, p. 42ff. Also note a typo intorduced on typesetting the article on p. 45, should be a half-thousandth, not 5 thou in the right column. Basically, Dana reduced carrier bearing preload from . 010" to . 015" used in the past to only . 003" and that resulted in zero and sometimes endplay in service.

 

[TomGolden]

I remember SledPuller saying that the 70's should be reset at 80k miles and the 80's should be reset at 100k miles. Guess he knew what he was talking about

Yeah, but just remember to use the Sleddy multiplier factor in there...



1 Sleddy mile == 1000 normal people's miles



At least as far as truck / equipment abuse goes.

 

[JKaltenheuser]

Where are you getting your Pow'r Lok from? Reider Racing told me they dont make a Pow'r Lok for the 80