TMC

The auto shifts are exactly the same tranny as a manual. There is no difference other than the computer doing the shifting. Never drove an ultra shift so don't know. As far as bullet proof they are identical. Only problem I ever had was that I wanted a 13 to have 1/2 steps instead of 10 speeds gap between 9 and 10.

 

Exactly the same? Does the automatic use a clutch or a torque converter? Does it use a hydraulic valve body for shifting? I've never heard of or seen an automatic that didn't have a torque converter or hydraulic valves.

 

They are mistakenly called automatics. Even though they do shift automatically. The first auto shifting transmission, three pedal, still had the clutch pedal. It just used solenoids to shift the transmission, and instad of a gear shift lever you had a control box, that allowed you to shift it manually by pushing a button up ever gear, or let it shift itself. They also have a hold feature if you wish to hold a gear.

There is a even newer autoshift that is a two pedal autoshift, no clutch. I've not kept up with this one but it uses air solenoids to control the clutch.

The automoatic your thinking about has a slush box. They are around, but usually seen in the smaller city trucks, dump trucks ect. I don't know if allison makes one big enough for the OTR application. You will be seeing one from CAT that is big enough.
http://ohe.cat.com/cda/layout?m=136641&x=7

 

Thanks Jorlee. You are dead on. The auto shifts have a clutch pedal for taking off and stopping or if you need to disengage for some reason. The ultra shifts have no clutch pedal. But they do not use a torque converter as most are used to. Most who knock them have never driven one. They have their good points and some bad like all.

 

That's interesting, I've only seen wet automatics from dumps and stake beds. It's the wet transmissions that can overheat on the hills so if these autoshifts are still using a clutch and non-hydraulic solenoids for shifting then I'm sure they are nearly as reliable as a standard manual aside from the increased number of moving parts. Thanks for the info.

 

Here is site to learn a little more about them. They are good for normal loads and not to hilly terrain. I drive one in CO, UT and other mountain states and wish I had at least 13. But overall it has been very reliable.

http://www.roadranger.com/Roadranger/productssolutions/transmissions/autoshift10-speed/index.htm

 

if you don't know, why do you assume they're not as reliable? the automatics simply use a 3" tall wizard on top of the transmission housing to shift the gears at the appropriate time, instead of the driver having to do it. and the wizard, he is quite reliable. it's not an automatic like you have in a car, any more than a straight drive in a tractor is like the straight drive in a car. the autoshift has a clutch pedal....the ultrashift (which I absolutely looooooooved......tool around washington DC traffic at 5PM and thank me later) uses a centrifugal clutch which engages at around 1,000 RPM if I remember correctly - but still uses the same 3" tall magical wizard to shift the gears for you. this should clear up any misunderstandings that folks have about auto tractor trannies.

 

Off topic, but is that icon picture from the movie 'The Duel?'

 

I had an automatic for a little while. Didn't really like it that much. Didn't have a clutch. Didn't seem to pull the hills that well. It was a newer KW daycab. Ended up having problem with the afterburner, I think. Not sure, it broke down twice in 10 days and I threatened to burn it to the ground unless they got me out of it.

 

My dad used to haul gas for years. He hauled 104k and his company tried one of the ultrashifts. He said that it would roll back on hills untill the clutch would engage.Has that problem been fixed or is it somthing you just have to deal with