PLEASE HELP - possible trans issue

[Z71Burban]

Hello everyone,

Very new here and tried searching up this issue but couldn’t really find anything similar so my apologies if this has been covered already.

I have a 2017 Suburban z71 5.3 6speed trans that just rolled over 80k. Literally OVERNIGHT (seriously not 1 single issue before) it seemingly turned into a Ford and does not know how to shift. At 70mph with the cruise set on flat roads, I’m at 3200 rpm in 4th gear. Also, shifting from park to drive, it’s a pretty hard shift but that’s the only hard one. It seems that it just doesn’t know what gear it needs to be in. Also, last night when coming up to a stoplight, it got all confused and just shut down on me. I put it in park and restarted and resumed like normal but something is definitely up. No dash lights or anything. Wondering if it’s maybe a flash update that needs to be done since there’s no clunking or anything? Has anyone else experienced anything like this? Just wondering if it’s an easy fix or if I need to take it in.

Thank you for your help in advance!

Nate
Belvidere, IL

 

[Joseph Garcia]

Do you have a bi-directional scanning tool to assist in troubleshooting?

 

[Doubeleive]

the engine shutting off really should not have anything to do with the transmission but I suppose it is possible.
I would start with the basics
check battery and cables, be sure the battery is good and that the alternator is charging. be sure the battery cables are clean and tight.
then check and verify fuel pressure.
then progress from there, but rule those 2 out first.

 

[Z71Burban]

Do you have a bi-directional scanning tool to assist in troubleshooting?

I don’t but a buddy of mine does. Maybe I should have him scan it before I take it in?

 

[Z71Burban]

the engine shutting off really should not have anything to do with the transmission but I suppose it is possible.
I would start with the basics
check battery and cables, be sure the battery is good and that the alternator is charging. be sure the battery cables are clean and tight.
then check and verify fuel pressure.
then progress from there, but rule those 2 out first.

Yea the engine shutoff was the wildest thing - that’s why I’m wondering if it’s possibly a CPU issue. After that I did check cables to make sure and those are all good and battery gage still stays WNL during long hauls so I’m assuming the alternator is good. How do I verify fuel pressure tho? I didn’t think of that

 

[Doubeleive]

Yea the engine shutoff was the wildest thing - that’s why I’m wondering if it’s possibly a CPU issue. After that I did check cables to make sure and those are all good and battery gage still stays WNL during long hauls so I’m assuming the alternator is good. How do I verify fuel pressure tho? I didn’t think of that

you can pick up a fuel pressure tester at most auto parts store's or harbor freight for around $25-30, autozone may also loan one for the same price you just leave the money as a deposit and get it back when you take the tool back.
then you want to connect it to the fuel rail and "if" possible stick it up under the front of the hood near the wiper area so you can see it while driving, usually they come with a extension hose for this purpose.

 

[Doubeleive]

the fuel pressure should stay fairly steady while driving, if you see it drop or it is all over the place and it's doing all the weird stuff and/or the engine shuts off then you know it's possibly a fuel pressure issue

 

[Joseph Garcia]

I don’t but a buddy of mine does. Maybe I should have him scan it before I take it in?

Yes, for sure.

 

[Z71Burban]

Yes, for sure.

Thanks man I’ll do that and post up on here with results. Appreciate it!

 

[Z71Burban]

the fuel pressure should stay fairly steady while driving, if you see it drop or it is all over the place and it's doing all the weird stuff and/or the engine shuts off then you know it's possibly a fuel pressure issue

Awesome! Thank you so much! I’ll give it a shot and see what happens!