DARK TRANNY FLUID?

[DAAJ]

I HAVE AMSOIL ATF IN MY 3500 D/A AND JUST CHANGED THE SPIN ON FILTER FOR THE 2ND TIME AFTER PUTTING 10K ON IT. TRUCK HAS 25K ON IT. I ORIGINALLY CHANGED TO THE AMSOIL AT 15K AND WHEN I CHANGED IT THEN IT WAS REAL DARK. THIS TIME IT WAS JUST AS DARK IF NOT DARKER. YOU SWEAR IT WAS MOTOR OIL. IS THIS NORMAL FOR THESE ALLISONS OR SHOULD I BE CHANGING FILTER MORE OFTEN? MAGNET DID NOT HAVE MUCH ON IT

[madmatt]

It sounds like you just need a good flush. there is a bulletin on this.... heres part of what it has to say on the matter.

Testing performed by Allison transmission indicates that this symptom shows a degree of viscosity breakdown of the Automatic Transmission Fluid (ATF). Viscosity breakdown occurs with vehicle usage and occurs more rapidly with increased loads and heat. If this condition is encountered the ATF and external spin-on ATF filter should be replaced and the transmission oil cooler lines and coolers should be flushed. Additional trucks used for towing or hauling should utilize the Tow/Haul Mode when the Gross Combined Weight is 75% of the vehicles Gross Combined Weight Rating. The use of synthetic automatic transmission fluid though not a requirement can be used if requested by the customer. Allison Transmission does market a synthetic fluid called TranSynd and it is available through GMSPO under part number 12378515 in the US and 88900701 in Canada. The fluid is a ship direct part and is available in cases of 12 quarts. The following is a summary of the owners manual recommended maintenance schedule for the ATF and spin-on filter.

2004: Spin-on filter only @ first maintenance service performed on the vehicle, Normal Service; ATF and spin-on filter every 50,000 miles, Severe Service; ATF and spin-on filter every 25,000 miles

2003: Spin-on filter @ first 7,500 miles, Normal Service; ATF and spin-on filter every 50,000 miles, Severe Service; ATF and spin-on filter every 25,000 miles

2002: Normal Service; ATF and spin-on filter every 50,000 miles, Severe Service; ATF and spin-on filter every 25,000 miles

2001: Normal Service; ATF andspin-on filter every 50,000 miles, Severe Service; ATF and spin-on filter every 25,000 miles

Owners Manual Severe Service Guideline: If the vehicle is mainly driven under one or more of the following conditions;

[DAAJ]

IT WAS FLUSHED AT THE 15K POINT JUST BEFORE I PUT IN THE AMSOIL. I HAVE NOT TOW ANYTHING YET AND CANT UNDERSTAND WHY IT IS SO DARK. TRANNY NEVER GETS HOT AND SHIFTS FINE,

[madmatt]

I'd take it to the dealer then. you may have something slipping/rubbing inside creating excessive heat and wear.

[2002GMC Durabeast]

Originally posted by DAAJ:
IT WAS FLUSHED AT THE 15K POINT JUST BEFORE I PUT IN THE AMSOIL. I HAVE NOT TOW ANYTHING YET AND CANT UNDERSTAND WHY IT IS SO DARK. TRANNY NEVER GETS HOT AND SHIFTS FINE, Daaj, take a sample of the fluid and send it to Oil Analyzers. I have a 2002 and I put Ams/Oil ATF in at 2,000 miles, tow in the hot Texas heat. My tranny temps have NEVER gone over 170 and it is as red as the day I put it in there.

[Brian DMT]

Durabeast has fantastic advice: I'd get a sample to Oil Analyzers - pronto. The lab results will not only tell you a lot about what's going on, but will protect you in the event of any warranty concerns.

The answers to a couple of questions could narrow things down - first, was it REALLY fully flushed, including the lines and torque converter? If you had it done, it might be worth it to talk to them and investigate the actual procedure that was performed and how much fluid was used, to see if there's a chance that any significant amount of original fluid was left in there. If you provided the fluid for a service center, how much did you provide? Note that the "initial fill" amount of 7.4 quarts is NOT the "total fill" amount of 13 quarts that actually runs in the vehicle. It's not hard to be in a hurry and read the "7.4" and go with it. Plus, if they used a fluid-exchange system it takes another quart or so to flush the last used fluid out of their system. So if they used 7 or 8 quarts vs 13 to 15 qts, that's a huge difference.

What I'm getting at here is that if a significant amount of petroleum-based ATF was left in there, then continued breakdown of a remaining portion of that fluid could easily account for the color, while the Amsoil content maintains your shift quality. (You may know that during the break-in period when elevated tranny temps are the norm, the fluid breaks down more rapidly.) Reports I've heard are that the factory fill is supposed to be Transynd, which can be run until 100k under light-duty conditions. While Transynd is a synthetic and thus performs better and withstands heat much better than the "dino" fluid, the comparative SAE and ASTM test data show that Amsoil ATF clearly outperforms it. Plus it costs about half and has even been approved by Allison (no warranty concerns whatsoever).

If you got a partial flush, then the solution is to do a full flush.

However, if you think that the tranny was actually flushed well, then there's a problem. Can't say what the odds are of fluid contamination, but that's not the most likely issue. Odds are that there's a heat problem. What does your tranny temp gage typically read? Under useage you describe, it should read 175F or below. For every 10F in temperature above that, the life of petroleum-stock ATF is cut in half. The Amsoil will actually run cooler than that, so there's NO WAY it should be above that temp under non-towing, non-hot-rod conditions. If it is, then there is a problem - such as a pinched/internally-collapsed line to/from the tranny cooler, or debris plugging flow through the cooler,etc. Those are only examples. The work will be to discover WHY the tranny is running hot. Once that's found, remember to document the situation (pictures and actual parts are recommended).

I'd like to know how your story turns out.

[madmatt]

transynd is available from Allison, but is NOT the factory filled fluid. It's just got the Allison non-syn. ATF in it. also (not directly related but..) Change the automatic transmission fluid and filter at 75000 miles if the vehicle is mainly driven under one or more of these conditions:

- In heavy city traffic where the outside temperature regularly reaches 32

[jbplock]

Originally posted by madmatt:
... Change the automatic transmission fluid and filter at 75000 miles ... MadMatt, I think you meant 7500 miles for the first Alli Spin-on change (?) smile.gif

It

[madmatt]

let me rephrase that statment....I started posting one thing then mid post started another.

At 7500 miles per GM change only the external filter, don't mess w/ changing the fluid. then change the fluid and spin on every 50K or every 25K if used hard. Allison does not recommend changing the internal filter unless overhauling the tranny.

Non allison equipped Gas engine light trucks can go till 100K miles, if not used hard.

[Onebigcanuck]

I had the same problem at 35,000 Kms (18,000 miles) it seems there is a problem. I was told to much idle while in gear will do it. If you believe that, I've got some summer vacation land at the north pole.

You might want to look at this link:

http://www.allisontransmission.com/service/faq/index***p?CategoryID=11

Good luck