Pete 579 2017 auto transmission issue
05-31-2024, (Subject: Pete 579 2017 auto transmission issue ) 
Post: #1
Pete 579 2017 auto transmission issue
Hello everyone,

I’ll start with my equipment which is a peterbilt 2017 579 with ISX15.
It has a 16 speed eaton auto transmission.
Truck is sitting at 807 k miles.

Recently I had a transmission issue where when I turn the truck off and go to start it again my transmission light on my gear selector starts flashing, dash flashes between F and N, and truck will not starts. I have changed the ECA and had it recalibrated and the issue stayed. Then the shop reloaded the relays and fixed the starting issue, I believe they swapped out the harness too.

I took a trip out and have been driving roughly 6000 miles without issues.
Earlier I stopped, got fuel and the transmission started beeping and flashing N. Would not go in 3rd gear or anything lower. Only gear it would go in was reverse. When putting it in Drive all
You hear is spinning and not grabbing gear. Then finally I shut it off let it sit and started it again. It showed F on transmission and service light was flashing but truck went into gear and I drove off. Once it hit the 10th gear it would not go past it. Beeping at me and staying in 10.

I’ve read online this could be caused by bad wiring, a 40 amp fuse on the Gen1 ECA or bad voltage reading to ECA.

I’m at a rest stop now in Wisconsin. Will try messing around with it more tomorrow. Any suggestions?
I cleared the code using the switch on/off x6 but it still would not shift past 10. No more flashing F or service light by the gear selector.

Any help would be appreciated.
05-31-2024, (Subject: Pete 579 2017 auto transmission issue ) 
Post: #2
RE: Pete 579 2017 auto transmission issue
Although I am not a fan of auto-sh#itter trannies... Here are some random thoughts that come to mind ...

At more than 800k+ miles.. when is the last time the clutch was replaced?.

When is the last time the XY shifter (and wiring) was replaced?.

When was the last time the tranny was dropped out of it for this type of major maintenance, inspections, and work?.

It sounds to me like 800k+ miles is getting long in the tooth for such things, and if the clutch, XY shifter, etc. is mostly still original.. then you have been very lucky with it.


Also, at 800k, that ISX engine is due for rod/mains + a second fuel pump guts replacement at that mileage too... so it sounds to me like its time to shut it down and do a whole lot of things (egr tune-up, have the DPF cans baked, etc.) to the engine too while your pulling the tranny. .. or if the engine is de-mandated, to also take the time to have the programming copied from the ecm, sent to me for review/inspected, to ensure it is not harmful to the engine, turbo, and/or the tranny as well.

User's Signature: ->: What I post is just my own thoughts and Opinions! --- I AM Full Of S__T!.
05-31-2024, (Subject: Pete 579 2017 auto transmission issue ) 
Post: #3
RE: Pete 579 2017 auto transmission issue
Hi Rawze, thank you for replying.

Clutch was done by company I bought it from when it was at at around 650.
One box I dropped it last year changed filter, sensors, dozers, all the goodies.
Rods and mains done last year as well alongside top set.
Waterpump changed not long ago.
Transmission oil changed last year as welll.

EGR tune up not sure about but I did read it in one of your post was looking to do that soon.

Tranny hasn’t had a new XY shifter, it’s the only outside part I haven’t replaced yet.

Other than doing that is there anything I can do to get back home? I’m only 7 hours away.
06-01-2024, (Subject: Pete 579 2017 auto transmission issue ) 
Post: #4
RE: Pete 579 2017 auto transmission issue

Changed xy shifter
Changed air filter regulator

Still same issue. Truck shifts through lower gears perfectly fine and smooth. Will not go past 10th gear. Beeps and service light flashes.

General codes nothing specific.

Could this be electric or a solenoid?

Taking it to the dealer Monday.

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