2005 Chevy 2500HD, NP1 TCase, 63K miles
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Is this Auto-Trak II fluid?
I have seen analytical ferrography that they mention and recommend. It is very impressive work, and I assume will be interpretted by a tribologist. I don't know how much it costs though.
I assume this is standard Dex III, this is not a transfer case that requires the Auto-Trak II. This was on the factory fill.
Indymac I'm not sure on the cost, I figured this gave me all of the info I really needed. Metal count was too high, and it was good to change the fluid. Run the next interval below the OEM recommended interval and see if things get better. I wouldn't know what to do with a ferrography report.
Indymac I'm not sure on the cost, I figured this gave me all of the info I really needed. Metal count was too high, and it was good to change the fluid. Run the next interval below the OEM recommended interval and see if things get better. I wouldn't know what to do with a ferrography report.
I don't think you need a ferrogram since this is the FF showing wear-in metals. I just wanted to mention that I've seen that work done on diff fluid and it was impressive. You don't have to do anything, a tribologist will interpret the picture for you.
dnewton3
Staff member
This is the 261/263 xfer case. There is actually four different cases for this GM truck application overall. There are manually shifted ones (261) and electronic shifted ones (263). There are also heavy duty ones for the 2500 series trucks and "super" duty ones for the 3500 series trucks. They are all of the same basic design, but the heavier units have slightly upsized shaft diameters, bearings, etc.
Yes, it is susceptible to "pump rub".
However, the source of Al is not the case; those are cast of magnesium. The source of the Al is like the pump body itself, which is made of Al. With both the AL and mag showing up in this UOA, I'd say you're in the beginning stages of pump rub.
There is NO FLUID ON EARTH that will avert this issue. It is a design flaw where the "clip" that keeps the Al pump from rubbing into the Mag case breaks or dislodges, and allows the Al pump body to contact and "rub" into the Mag case. Believe it or not, as soft as Al is, it is stronger than Mg when it comes to abrasion. Hence the term "pump rub".
The only solution is to pull the case off, pull it apart, and put in a mechanical fix (Riverside Gear, Kennedy, Merchant Automotive, etc). It is MUCH cheaper and easier to do now BEFORE the hole rubs all the way through! I did my "upgrade" at just 10k vehicle miles in an afternoon. It is worth the piece of mind. I used the Riverside gear; it was $55 at the time. FAR cheaper than replacing a whole t-case or having one reman'd, after stranding you on the side of the road. It is never a question of if it will happen, but when it will happen. It looks like it has started for this vehicle.
This UOA did exactly what we want them to do; predict the onset of failure BEFORE is becomes a catastrophe. While I cannot assure you with 100% certainty that this has started, you have the tell-tale signs. Your $15 UOA may have saved you $1500 in repairs!
Yes, it is susceptible to "pump rub".
However, the source of Al is not the case; those are cast of magnesium. The source of the Al is like the pump body itself, which is made of Al. With both the AL and mag showing up in this UOA, I'd say you're in the beginning stages of pump rub.
There is NO FLUID ON EARTH that will avert this issue. It is a design flaw where the "clip" that keeps the Al pump from rubbing into the Mag case breaks or dislodges, and allows the Al pump body to contact and "rub" into the Mag case. Believe it or not, as soft as Al is, it is stronger than Mg when it comes to abrasion. Hence the term "pump rub".
The only solution is to pull the case off, pull it apart, and put in a mechanical fix (Riverside Gear, Kennedy, Merchant Automotive, etc). It is MUCH cheaper and easier to do now BEFORE the hole rubs all the way through! I did my "upgrade" at just 10k vehicle miles in an afternoon. It is worth the piece of mind. I used the Riverside gear; it was $55 at the time. FAR cheaper than replacing a whole t-case or having one reman'd, after stranding you on the side of the road. It is never a question of if it will happen, but when it will happen. It looks like it has started for this vehicle.
This UOA did exactly what we want them to do; predict the onset of failure BEFORE is becomes a catastrophe. While I cannot assure you with 100% certainty that this has started, you have the tell-tale signs. Your $15 UOA may have saved you $1500 in repairs!
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