2nd Gen Non-Engine/Transmission Differential question

[BoeingDiesel]

We’re back in CA. for the holidays so I’m using my ’99 for transportation. I don’t have that much to do and the wife is busy with the kids and whatever else women do during the day.
It’s been quite some time since I had the differential serviced (about 25m miles) so I decided to do it myself. The inside of the cover didn’t appear too dirty and the fluid was light brown in color but I found (2) very…very thin metal flakes attached to the housing magnet that were between 2-3 MM square. The material was so thin I would take it for being aluminum foil but it definitely was steel. I cleaned, re-assembled added fluid and 8 ounces of friction modifier and everything seems to be okay. I haven’t noticed and noise but as we all know 2nd Gens’ are not the easiest of vehicles to detect a different noise. So my question is; should I be concerned and take it to a professional or could it be just normal wear? The truck has 389m miles on it and always well maintained.
Any ideas or recommendations are greatly appreciated.
Thanks
gregg

 

[SAndreasen]

I always rotate the differential and check for any wear on gears that I can see . If its been a long time the fluid will be very thin and brown I assume it's been more than 25 miles and less than 25 million not really sure of the value of m here but I wouldn't be to worried .

 

[BoeingDiesel]

I always rotate the differential and check for any wear on gears that I can see . If its been a long time the fluid will be very thin and brown I assume it's been more than 25 miles and less than 25 million not really sure of the value of m here but I wouldn't be to worried .

Thanks SAdreason, I should have been clearer. It’s been about 25,000 miles since it was last serviced and the 2 flakes I found were 2 to 3 millimeters square and the truck has a little more than 389,000 miles on it. I should probably add that the majority of those miles were spent on the California freeway system and we did use the truck for light towing when I first got it in August of ’98. I didn’t rotate the axle but I will say there seemed to be minimal wear on the ring gear and I didn’t see any missing teeth on the tone ring. Probably should have rotated the axle to be sure.
Thanks again
gregg

 

[MPalachuk]

I would worry about it being a shim from under the carrier bearings, It is kind of common for the bearing to spin and peal the shims out. If the bearing is starting to spin you have to worry about the race spinning against the housing and damaging it. With all of that going on it will lose the preload on the carrier and after time will let the carrier move around and cause lots of other problems.

 

[BoeingDiesel]

I would worry about it being a shim from under the carrier bearings, It is kind of common for the bearing to spin and peal the shims out. If the bearing is starting to spin you have to worry about the race spinning against the housing and damaging it. With all of that going on it will lose the preload on the carrier and after time will let the carrier move around and cause lots of other problems.

Thanks MPalachuk. If this is the what's happening are there any symptoms re; noise, vibration etc that will be present?
gregg

 

[MPalachuk]

Not if you catch it early, If you wait till you hear or feel a problem it will just be worse. My information comes from having a gear repair shop for 12 years on my own and my Dads business of 32 years for gear repair. Good luck and hope all comes out well.

 

[Bob4x4]

The Dana 70s tend to loose carrier bearings,if let go long enough it will take out the housing.If it was shim material you should have pried the carrier side to side to check for play

 

[MPalachuk]

Also look in there, It may not move side to side unless it is really loose.

 

[BoeingDiesel]

Thanks guys for the info…looks like I better get it into a shop that does this kind of work. Any idea what a rebuild would cost for this type of differential?