Type of automatic in your truck?Differences?

performance mode doesn't make all that much of a difference, truthfully, unless I'm going downhill, I haven't hardly used M mode, and even then, I'm finding more and more to like about the power leash engine brake holding system. SLC to Denver Tuesday evening, 4,400 in the can, dropped off Genesse with engine brake on medium, power leash set to hold 46 mph, never touched the brakes, but had to give it fuel a couple of times. Even dropping down Parley's empty Tuesday morning, set the engine brake to 65 mph and let it run.

 

Hopefully the "Navistar Exclusive" contract that Allison has going on doesn't last too long. Allison has a good transmission in the TC10 and it would be great if in the future it finds itself as on option for anyone in the industry who wanted it. I know I'd be perfectly happy to have one behind a DD15.

They're big transmissions though. When I went to maintenance school for them I was amazed by their size. I also wondered how many there are out in the wild right now, and how long it would be before I actually saw one in my shop. Allison has been very tight lipped on production numbers. Not only are the numbers low, they have very long (500k) maintenance intervals. (Then we had one come into our shop last month because one of the clutch packs in the trans had decided life was no longer worth living).

On the service side of things, they're kind of a pain in the butt at the moment. Allison is still in the phase where they're collecting as much data as they can on what's going wrong with the TC10 in the field so if we get one in.. We have to go through this kind of annoying process before we can really begin troubleshooting. We actually have to provide a bunch of data direct to Allison and get approval to do work. Good times for those of us on the West Coast having to deal with engineers in Indianapolis. After a certain time of day, yeah.. Going to be tomorrow when we hear back.

 

YES, they are HUGE, I have to wonder if the physical size is causing some concerns among other manufactures? Plus they are what? 350# heavier than an Ultrashift?

My biggest issue with any of the ATM's is the lag time in downshifting when climbing a hill, and although that has been improved greatly, as long as you have a clutch it will never be eliminated, the TC-10 simply doesn't have that issue.

It just really impressed me as the test truck/trailer weighed around 58,000 and that is just above where we operate (54,000) at that weight is pulled seamlessly away from a stop like it was an empty trailer.

Since you are into Allisons let me ask you this, how much of a hit would I take on fuel mileage if I just went with a 4000 series, I know it is only 6 speeds but they seem to work well in the big motorhomes that are right at our weight, I just assumed that parasitic loss due to being a full automatic would be greater than the gear cut TC-10.

I have asked this question before but no one seems to be able to give me a good answer?

Thanks Stan

 

my DD12 which is a mercedes shifts quicker and smoother then I can
might just mean i cant shift
little hesitation from a stop

 

No doubt about it CY DT12 is a nice unit, but you still lose rpm on uphill changes what I liked about the TC-10 is that you have virtually no loss of rpm at shift point.

IOW, if you have big torque (like your DD15) it's not an issue, but if you are running a smaller motor, say 9/10 litre that rpm drop IS a big deal, I think that is why most of the smaller motor apps run the Allison full auto with torque converter, it makes it seem like a bigger motor.

Problem with the full automatic is parasitic loss in the tranny, whereas the TC-10 is a gear cut transmission once you get past the TQ convertor, best of both worlds.

My fear is that with Allison tying themselves to Navistar they may have shot themselves in the foot, I can see no way for them to recoup their cost investment in that platform on just Navistar products, even if it was across the board use of that tranny.

I guess time will tell, interesting side note, at the show when I drove that truck with the TC-10 you had to fill out a questionnaire on what your favorite or preferred model of truck and engine was, seems they are already looking for another partner.

I doubt you will ever see the TC-10 in the DTNA products as it is too close to the DT-12, I can't see why they would consider it, same with Volvo/Mack, which leaves Paccar which has been pushing the Cummins/Eaton product.

Guess we will have to wait and see.


On second thought, Cummins should just buy International trucks and offer their motors exclusive, be the best thing that could happen to Navistar, they have killed their rep. with all of the non-SCR hysteria.

 

1) There actually isn't much in the way of parasitic loss in Allisons because of the lock up torque converters. By the time you're in 2nd gear the converter has locked up and the transmission is operating in direct drive mode and no converter slip is going on. (1000/2000, 3000/4000 series)

2) As far as fuel economy hit.. A good answer may be hard to give because of what all goes into fuel economy beyond just the transmission itself. At your weights a 4000 would work, but a lot of things will factor into whether or not it would be a good fit. A local beverage distribution company I do field service work for runs a fleet of trucks that is 90% Allison equipped (all 3000 series, trucks registered to 48,000/54,000lbs), but I don't keep track of the kind of fuel economy they get. They obviously do a lot of local delivery work and spend little time out on the open highway. A 4000 would handle your weights just fine but, again, I'm sad to say I can't lock down if it would be a benefit to you from a fuel economy standpoint. It all depends on how much of an RPM split you'd find through each gear shift and if that would put your engine out of it's optimum RPM range too often while you were getting up to cruising speed. All the same stuff regarding your tire size, rear end ratio.. blah blah blah applies. The key for fuel economy is you want each gear you go through to offer the least amount of RPM split at each shift. An engine that only drops 200rpm per shift while keeping in it's optimal power range is going to use less fuel than one that has a 500rpm drop per shift.

Sorry if that is still an ambiguous answer, but it's all I have. I'm not too proud to admit that just because I work on the things for a living doesn't mean I have all the answers.


Oh, and speaking of the TC10 and torque converters.. TC10's are 1st gear lock up. TQ convterter locks and transmission is direct drive from the flywheel after 3mph.


As far as the exclusive partnership goes with Navistar/Interscraptional... We'll see. I, too hope that it is short lived and the transmission becomes available to anyone who wants to pony up the cash.

 

It does, unless your company disables it like mine did. They also disabled the manual feature. When pulling a good grade, I would try to downshift it at about 1300-1400 rpms to keep good momentum going up. Now, in economy mode and no manual shifting, it lugs down to 1000-1100 before doing the downshift. I lose about 5-8 mph on most longer grades.

As for disableing the manual fearure, where I REALLY hate it is when pulling a grade in a snowstorm. I like to hold a steady rpm and the same gear when the road is slick. The first snowfall, I shifted it to manual to hold the gear so it wouldn't upshift, and the #### thing defaulted to neutral. Not good.

 

I think it's funny that two of the biggest no-no's in truck driving are now ok with an automatic. Coasting out of gear and shifting over railroad tracks...lol!

That being said, for the most part I really like my automatic (Volvo I-shift), especially since I'm currently running local in Eastern PA and New Jersey, where traffic jams and city driving is the norm.

As for the the DT-12 transmission, the e-coast I think would scare me a bit, especially when the pavement is slick. When it senses that it needs to go back into gear does it lurch or throw torque too quickly, or is it a smooth and steady transition?

 

the DD12 is smooth smooth smooth
was one day before I got over that it was coasting
I dont know the ins and outs of the tranny
being just a dumb company guy but I am impressed
I dont pull Donner any slower then the 13 speed on the same engine

Last truck impressed me this much was 1980 when i went from a 671 Detriot to a 425 Kitty

 

Who and How does one get the Tranmission programmed to add Performance Mode ?