Eaton ultra shift problems


Active Member
Thread starter #1
I have a 05 387 with a 10 speed eaton auto shift tranny sometime feels like it goes in and out of gear indicator light blinks like a miss sometimes acts up then may go 200 miles perfectly just pulled it out of shop no codes replaced spend sensor clutch is good so is 9 and 10th gears only acts up it 10th put it in 9th works fine anyone have this problem don't want to throw parts at it only thing is harness or ecm just want to be sure before I change them


curmudgeon extraordinare
Sorry bub. What you are describing is exactly why I won't touch an auto in a semi truck.


Professional Pot-Stirrer
I'd go wiring first... as bad as the roads are, you could certainly have wires chaffing, and corrosion on connectors setting in.


Active Member
Thread starter #5
Yeah kinda narrowing It down to that gonna clean and check grounds when I get home it's got to be something stupid dealer has looked internal trans clutch is good new harness and new sensors


curmudgeon extraordinare
Yeah kinda narrowing It down to that gonna clean and check grounds when I get home it's got to be something stupid dealer has looked internal trans clutch is good new harness and new sensors
Did it start before or after dealer messed with it? Or was that why it was taken to the dealer?

If it started after, then check their work first.


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Thread starter #7
First trip out only had truck 1 month been in shop 2 of those weeks


Well-Known Member
Jefro, just had problem w/ Ultrashift, took to Kw in Van Buren, Ar, excellent mechanic[Danny} discovered chaffed wire going to tranny controls, took $2.30 roll of tape, spend $974.00. Expensive trip but solved problem and truck is back working! Good Luck!!


Active Member
Thread starter #9
Hell yeah they changed full harness haven't ran far yet will know tomorrw


curmudgeon extraordinare
Be glad they replaced the entire harness. You'll be glad they did when you aren't chasing the same thing 5 times in the next 6 month.

Look past just this one repair and think about what caused that worn spot. Then realize there are likely several places that harness was bad.

I have replaced harnesses on my truck and opened then up afterwards to see all the damage that is in them. These mechanics that think they are doing you a favor replacing or patching that one little spot aren't.
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A note on ultra shifts, if it will work in manual but not normal it is generally electrical, if it does not work in either it is the XY shifter.
Thread starter #12
Nope still screwing up . Was idling and truck sounded like it was missing looked and gear indicator light it was flashing I neutral just like in 10th I have no clue what to even look for now can't afford to throw parts at it the said they ordered another harness that was custom made have no clue where that one goes this is driving me nuts
Thread starter #13
No worn spots eaton rep told them to replace fighting with them because it's so intermediate I can't get it to do it when they drive it it went 200 miles this time before messing up and then messed up all the way to Atlanta
Is it popping back out of tenth?

I wonder if it is a transmission problem rather than an ultrashift problem. Basically you just have an Eaton 10 speed with a computer and a box on top.
I wonder if a shift fork went out?
Thread starter #16
They said they looked at the teeth there is a bulletin about that laid it was ok
Thread starter #17
I have video of it doing it won't let me upload it
Thread starter #18
Well pulled fuse out of power wires coming from battery box and light started blinking fuse was lose went woo hoo think I found the problem nope still screwing up so it's losing power just not long enough to throw codes pritorylink is ordered so if that's not it I have no clue really don't want to replace computer not knowing if it is messed up
I am still going with it being a transmission issue boss. The Ultrashift problems are hanging between gears (programming problem), Not shifting at all (bad XY shifter), or losing shift point (bad harness).

When it shifts up it goes into 10th fine Correct?
Thread starter #20
Yes just indicator light starts to blink like its going out of gear or loading power for a sec then runs fine for ten 15 mins does it again shifts great only happens in 10th