2nd Gen Non-Engine/Transmission Dana 70 hub defect on '98.5

[Vaughn MacKenzie]

Ever since I bought my '98.5 Ram 2500 2wd auto in May 2012 it has always had a bit of tire vibration, especially around 70mph. It got considerably worse after installing 20" aftermarket wheels, it also had a rhythmic bounce at 40mph. I always thought it was either the wheels or the low profile tires. But no matter how I had them balanced, or rotated, the vibration always seemed to come from the back.

A few months ago I had the back of my truck jacked up with the engine running and trans in gear to diagnose a noise. As the wheels were spinning I noticed something. The entire tire and wheel on the passenger side was moving up and down noticeably, as though it was off center! It didn't wobble, vertically it spun perfectly true, but the wheel acted as though it was mounted to an eccentric hub. I loosened and tried remounting the tire, to no avail. I pulled it off and repeated the process and I could see as the hub turned the lugs were visibly off center. Wow!

At this point I wasn't quite sure what to do. I did some crude measuring but it was off-center at least 1/16" of an inch, closer to 1/10". I did some researching online and learned there is a spec called stud circle runout, and mine was out by a mile. General rule of thumb .050" is maximum runout. I called some shops to see about possibly redrilling it but I was met with all kinds of skepticism and even outright denial that this could actually be a problem. I was pretty much told by one shop I didn't know what I was talking about.

I posted on NW Bombers and I was advised there that redrilling wouldn't be a safe move. I searched eBay and Craigslist for used hubs but came up empty. I called around to see about obtaining a new hub but they were very pricey. Eventually I found a listing on eBay for a pair of Dana 70 hubs off a '97 so I grabbed them. When they arrived I verified the measurements and installed it and problem solved! My truck rides like it never has before, it's fantastic!

This issue was a new one for me. You would think that naturally for good ride quality hub components would be manufactured to a high degree of precision, but apparently that's not true 100% of the time.

Vaughn

 

[SnoKing]

Ever since I bought my '98.5 Ram 2500 2wd auto in May 2012 it has always had a bit of tire vibration, especially around 70mph. It got considerably worse after installing 20" aftermarket wheels, it also had a rhythmic bounce at 40mph. I always thought it was either the wheels or the low profile tires. But no matter how I had them balanced, or rotated, the vibration always seemed to come from the back.

A few months ago I had the back of my truck jacked up with the engine running and trans in gear to diagnose a noise. As the wheels were spinning I noticed something. The entire tire and wheel on the passenger side was moving up and down noticeably, as though it was off center! It didn't wobble, vertically it spun perfectly true, but the wheel acted as though it was mounted to an eccentric hub. I loosened and tried remounting the tire, to no avail. I pulled it off and repeated the process and I could see as the hub turned the lugs were visibly off center. Wow!

At this point I wasn't quite sure what to do. I did some crude measuring but it was off-center at least 1/16" of an inch, closer to 1/10". I did some researching online and learned there is a spec called stud circle runout, and mine was out by a mile. General rule of thumb .050" is maximum runout. I called some shops to see about possibly redrilling it but I was met with all kinds of skepticism and even outright denial that this could actually be a problem. I was pretty much told by one shop I didn't know what I was talking about.

I posted on NW Bombers and I was advised there that redrilling wouldn't be a safe move. I searched eBay and Craigslist for used hubs but came up empty. I called around to see about obtaining a new hub but they were very pricey. Eventually I found a listing on eBay for a pair of Dana 70 hubs off a '97 so I grabbed them. When they arrived I verified the measurements and installed it and problem solved! My truck rides like it never has before, it's fantastic!

This issue was a new one for me. You would think that naturally for good ride quality hub components would be manufactured to a high degree of precision, but apparently that's not true 100% of the time.

Vaughn

Maybe that is what is wrong with new 4th gens that no one seems to be able to figure out. SnoKing

 

[Wayne M.]

Excellent detective work Vaughn. Thanks for sharing. Shame on the naysayers, but I agree about not reindexing/ redrilling. Structural concerns. Buying the replacement hubs was worth every cent.

 

[Joe Mc]

Vaughn, I had same issue from right rear on mine for the longest time. I eventually acquired a D70 drum to drum from a first gen (not in an effort to solve the issue, for another reason) and wouldn't you know it, after all said and done with install of the fist gen unit, no more issue.

 

[Vaughn MacKenzie]

Joe it's interesting to hear someone else had the same issue. I imagine it's not an entirely uncommon problem, and often times goes unsolved.

 

[BigPapa]

I'm going to check mine today.

 

[Joe Mc]

I wouldn't have thought the studs could have been off-center and even took the axel out to check with a dial indicator for trueness. At first I thought it was a tire balance issue, then a wheel bent issue (had the stock "potato chip" chrome wheels when I got it), even after I bought new wheels the phasing vibration at speed was always there. I'm just glad after the rear (drum to drum) change that I no longer have the vibration.