autoshift transmission

Aside from scanning for any fault codes, inspecting the wiring harness for damage, and sampling the oil in the gearbox, there isn't a whole lot that be done to tell if an autoshift will last or not. The eaton auto shift isn't much different than the RTO series gearboxes internally, and I've seen those boxes last into the million mile mark with little more than oil changes in a line haul application. However, local and short distance hauling can cut that number in half though. The bearings in the rear section and the synchro clutch really take a beating in those applications. The electronics are what dies on autoshifts and about the only thing you can do to prevent it is to keep the wiring harness tied up nicely to prevent abrasion on sharp metal parts and keep as many connectors as possible away from water spray. If you really wanted to be proactive in maintenance, you could change the XY shifter, wiring harness and all the sensors before they fail (my guess would be around 750k miles). However, those parts aren't cheap. The elclectonic bits often die with little or no warning though.

The other things that can be done to keep them alive also pertain to manual shift boxes as well, such as: Keeping drive lines lubed, tight, and addressing any shaft vibrations immediately, physically inspecting the trans oil for coolant contamination periodically (most new trucks have trans oil/engine coolant heat exchangers and they do fail) and above all, drive it nice and keep good clean synthetic oil in it (and keep it full).

 

thanks badmotorfinger, the truck i'm looking @ is an 03 with over 750k on it

 

That one has a few miles on it!

Here's my $.02: Way more often than not, older and/or high mileage autoshifts trucks can be had for cheap. People are afraid of them. A friend of mine runs a gear shop in LA and has converted a bunch of trucks from autoshifts to standards for the local Freightshaker dealer because they flat couldn't sell them. If you are comfortable working on your own stuff, get ahold of the software (and the pieces to make it work), download the service manual from Eaton (it's public...and free), carry some spare parts (used stuff will work fine, and pops up on eBay periodically), and have at it. You will work on it from time to time, but the money you can save at purchase will save you a fair amount of scratch.

 

The ultrashit plus is great. Im a technician not a mechanic. That's probley why u got some bad info on them. LoL a mechanic replaces parts a technician finds what happens and fixes the root cause.

 

While in a heavy LA traffic did you get 'CA' sign (Clutch Abuse) and how often?


I finally got two of our ultrashift trucks in for a scan! I've been really busy lately, so sorry for the late reply.

The first unit is mostly subjected to heavy LA traffic, and has had the best meathead/hammerhead/steering wheel holders the world has to offer as operators. In 17,000 miles it has had 4 different "operators". Here is a clutch heat historgram right out of the trans ECM



TABLE Clutch Temperature Histogram
Temperature (degC) Count
100 5726
150 2287
200 82
250 1
300 0
350 0
400 0
450 0
500 0
551 0


Clutch Overspeed Count 0


TABLE Clutch Abuse
Count 1
Elapsed Time (s) 34.200000


As you can see, there is one instance of clutch abuse with the temp above 250 degC for 34 seconds. 250 degC is about 480 degrees farenheit. It's not enough to melt stuff, but it will soften the metals on various clutch parts, and I can see why Eaton would set it there. The heat sensor is in the side of the bellhousing not far from the clutch cross shaft, and I imagine that the clutch face temperatures would be much hotter.

Now, here is a clutch histogram for our best driver. He doesn't do near as much LA work, but does sit in traffic from time to time, and is what I consider to be a very good driver. This truck has approx 30,000 miles on it

TABLE Clutch Temperature Histogram
Temperature (degC) Count
100 6243
150 161
200 0
250 0
300 0
350 0
400 0
450 0
500 0
551 0


Clutch Overspeed Count 0


TABLE Clutch Abuse
Count 0
Elapsed Time (s) 0.000000

As you can see, there is a pretty big difference in the histograms. Currently, both trucks are set with 2nd gear being the default start gear, and 3rd gear as the maximum start gear. "Default start gear" means that whenever the truck is started and placed in gear, it will start off in 2nd gear unless you manually select a different gear, and when you do so, it will continue to start in that gear until either 1) you select a different start gear, or 2) you turn the key off. I think that the LA truck is being driven in traffic with 3rd gear being selected at startup and not changed by the "operator" (if that's what you want to call him) to suit low speed conditions...and as a result the clutch is being slipped excessively in traffic. I have adjusted the maximum start gear in the LA truck to 2nd and I will recheck the histogram in another month or so.

Hope this helps someone,
Your friendly neighborhood diesel mechanic.

Notice: I refuse to call myself a technician. I consider the "technician" bit to be a sugar coating, and it's like calling the guy in the pit of your local Jiffy Lube a "Petroleum Transfer Engineer". I'm a diesel mechanic, I'm fargin good at it, I enjoy it, and that's the way it is

 

looking at your data it looks good as I've see far worse. I would keep both default gears the same but change the shift points. I don't know Engine you have or model of trans, but with a ISX and a RTO-10910B-DM3 i would set the shift points to 1800 with mid inerita. Ive done that with a few companies and they love it. speaking of it is Dallas traffic and not LA (witch I heard is 50 times worse).

 

Hello, I have an '08 T660 with a Cat C15 set at 1650 ft/torque. My transmission is a 13 ultrashift (no clutch). Kenworth wont raise my cat's output to 500/1850 since the transmission tops @ 1650.
It's been giving me some issues here and there, mostly "torque locking" and rarely but one on a coast to coast load the even numbers (7, 9, 11, and 13) would not go in.

My questions if you could answer are, do I jump in and start changing harnesses (3) sensors, clutch, and fluid or would it be better (cheaper) for me to stick a new tranny in?
If so I'd like an 18 ultrashift plus.. what kind of numbers would I be looking at?
How much does it cost to drop a standard super 18 in this truck?

Thank you

Forgat to mention my truck has now 663k on the clock

 

It was my question. Thank you very much for your comprehensive response.

Thats why I booked maxtorq version of ISX - to force manufacturer to pair it with MATCHING maxtorq gearbox.

Could you please explain how it happens and how you resolved it. Thanks.

 

My C15 is rated up tp 625/2050.. I just want 500/1850, but was told housing or something on tranny wouldn't like that.

The gear jumping was fixed by replacing splitter valve ($350 part) I was told by KW 3 times it was a bad wire in one of the 3 harnesses and it would take "a whole day" to find it. Furthermore a corner mechanic fixed it in 10 minutes and for $50.







what works for me when torque locking, in a kw '08, truck wont start, get in, shut door, insert key in the ignition; then you will flip the key from the on position to accessories "8 times" and stop and take key out.
Wait for a minute, re-insert and start.

Seems this resets the tranny somehow.

 

Wow. Outdated? The TC 10 TS was just introduced this last spring. If that is outdated, then the auto shifts out there now are dinosaurs.