Lost 3rd Allison in 20k

Mine did not leak fluid. Never a drop, after 5 rd hrs, parking in the same spot for days. I always look, it's an easy check for early problems...And, just checked new ones. At $1,000, I dont imagine Allison cares to include it. I had their "Professor Transmission" give me a 3 minute "education" of how the "Cummins can kill transmissions, simply by having a miss. It happens sometimes. Or the ride height. We see it a lot." I said wouldn't driveline problems manifest different damage? (Mine have always been clutches)Seals, bearings, races? I was a heavy equipment mechanic in the Army, and have run it 35 years out in the woods. Probably wouldn't make it very long, and have an outstanding reputation with all my former employers if I let 500k machines break down because of poor maintenance or didn't detect small things before they became big ones. SO, then I had to pay about $265 for them to check ride height. It is fine, thanks. Then they sent the Cummins guy, with his computer to capture all the codes from the engine. Those, they sent to engineers in California. Nope, apparently nothing there either. After that, Allison kinda quit talking to me. I went to the service manager to be sure and asked, "So, Allisons position? No help?. He said "That's correct. Out of warrenty" I understand that, but you'd think, someone would want to know why! Thay have such an awsome reputation. You could probably throw rocks in the dang things, and your grandkids will still be driving it. Hundreds of ideas from several RV forums, dozens of transmission mechanics.... and no one mentioned torque converter once. Amazing. So many sincere thank yous!

As a tech for various GM dealerships, I've installed numerous factory reman or new transmissions, even a couple of Allisons in Duramax pickups.
They all come with new(or reman)torque convertors. 
There is no way to clean a torque convertor without cutting it apart(in fact, you can't get all the old, nasty fluid out of it no matter how long it drains), and no manufacturer is going to stand behind a new tranny with an old converter full of stuff from the old tranny).  Same reason they'll require the lines and cooler to be flushed.
In this situation, I think I might request that the transmission cooler itself be changed out(assuming it's not part of the radiator)due to having 3 blown transmissions worth of crap circulated through it.  If its part of the radiator, I assume it would be too much money to replace and you'll just have to live with a flush.

Old Crow  - can you tell us the function of a torque converter in an automatic transmission?  This whole thread is becoming an excellent learning tool for me. Great to know that all the remans come with a torque converter.

The torque converter transmits engine power to the transmission. It's the big donut shaped thing between the engine and transmission.  Basically, it's two impellers next to each other in a container of transmission fluid.  When the engine drives one impeller, the fluid transmits power to the other one connected to the transmission.

The fluid allows some slip between them, so the engine can idle when the transmission is in gear.  As the engine speeds up, more power is sent to the transmission.  The slippage converts engine RPM to torque, thus the name.

The slippage also wastes some power while creating heat in the transmission fluid, so modern torque converters also have a lock-up clutch.  The torque converter does it's thing while the vehicle is stationary or just starting up, then the clutch engages to create a direct connection between the engine and transmission, conserving power while also keeping the fluid cooler.

Back in the day when I hung around with some guys who built and raced IMCA Modifieds in the 80s and 90s, they liked the GM two speed automatic transmission in their race car, but to reduce rotating weight, they eliminated the torgue converter, and just used an inline ball valve in the pressure line as a substitute, opening and closing the valve as needed to get the car going or to stop it with the engine still running.

Bill N said:

Old Crow  - can you tell us the function of a torque converter in an automatic transmission?  This whole thread is becoming an excellent learning tool for me. Great to know that all the remans come with a torque converter.

Click to expand...

What Lou said.  More basically. it takes the place of the clutch in a manual transmission.

Allison is really hoping glycol contamination is why. Looked hard at radiator and cooler today. Separate, I'm pretty sure. One for engine and bottom one for trans. A thin metal bracket between them. Top has much larger tubes, bottom tubes are very thin, and 2 lines go to trans. It is a manifold type, not a continuous loop. And surely updated by previous owner. They seemed to spare no expense to make this home luxurious and nice, and mechanically sound. So, probably not torque converter if it's changed each time.  I can't find ANY charges for fluid sample tests after any of the failures. I think I would have ordered it. I'm going to take one in the a.m. and overnight it to a fellow that will test it for everything from Aardvark to xylophone. He's an engineer and very curious.

More good TC lessons and now I am beginning to understand how I blew my tranny a few years back.  Expenses never stop.  Yesterday brought coach home after having half of the windshield replaced (see thread: Winnie fails to score 3 pointer) and the wife was following me.  When we get home I tell her how that narrow road looked flat but it seemed to really crown off heavy to the right.  Then she tells me, no you were leaning pretty heavy to the right the whole time.  I put the coach away in storage but now I guess I have another problem to troubleshoot.  Will probably do that as I am winterizing it this week.  I know I have one very slow leaking tire on the right side rear but it is still at 75 lbs so that should not be the cause.  Suspension - hopefully not a broken spring. That may cause another new thread.  Thanks for the TC info guys.

You'll never believe this. I will send reciepts to any that don't.  Replaced trans with Weller reman, excellent reputation. Went to pick up. While paying $7,300 approx, we discussed diagnosis/causes. They checked everything. 2 samples to two labs revealed no contamination other than clutch particles. Allison filters were used. All engine and driveline measurments were well within spec. They don't know what is the reason this is #4. BUT... #4 BROKE DOWN BEFORE I LEFT THE PARKING LOT. There....believe THAT if you can. I probably would stop reading this thread at this point. It's like I said "I won the powerball and got struck by lightning today" The odds of that happening, are probably less than the odds of what did happen today. I am going to Spokane if it kills me. At least, this is warranty work. Shoulda seen the look on the service manager, poor young lady. Upper managment is involved (hence the very thorough search for the causes) and she had to notify them, and EVERYONE wanted to see the rear end of this rig moving away. Me most of all. If I  had some money, I'd look for a good used tow truck... thanks for listening and, it really did happen today.

The powerball is now 1.6 billion. Go buy a ticket FAST.  That could buy a lot of trannys.  Your story is one of those that should be on the old program 'Believe it or not."

BTW - the suspension problem I mentioned in my previous post is no big deal.  No spring broken and the 'lean' is about 1/4 inch max and zero when the water tank is drained and the right side tire that was low is pumped up.  Never seen a tire leak that slow - about 6 lbs in 3 months so I suspect it is in a connection between the valve extension and the valve stem to the rim.  Will do a soap check on it next trip.

Bill

New reman, internal wiring harness failure. 6 hr. warranty job.

A conclusion  (we hope). The ECU/TCM was commanding multiple clutch simultaneous engagement. A calibration error. Glad this is almost over.

FWIW:  I would install a new separate cooler & re-route the lines from the tranny to the fittings on the new(er) cooler.  To determine capacity for the new cooler, I'd ask the Allison people for suggestions.