2010 Silverado 4L60E Issue (PO717)

QuickSilverz · January 1, 2016

Hey guys,

Looking to get a little insight on a problem I have been experiencing for about 6 months now. The truck is a 2010 Silverado with the 4.8L engine and 4l60e transmission. Pretty much bone stock besides 4.11 gears in the rear and a corvette servo. Anyways, the issue is a hard shift from 1-2 gear. I'm talking about slamming into second gear. It doesn't happen very often. In fact I can drive the car 5 days a week and it may only happen on one of those days, but wont go away until I shut the truck off for a few hours. Doesn't seem to matter if it is hot or cold, sometimes it will do it as soon as I pull out of my driveway and other times it will do it once I have been driving around for a bit. On a couple of occasions I have seen a check engine light and received code PO717, which is no signal from input shaft sensor. Usually when it starts to shift hard though, there is no engine light or stored trouble codes. I took it to a shop expecting to have them replace the input sensor, but they told me they couldn't find anything wrong and drove the truck around for a while trying to replicate the problem and couldn't get it to happen. I also replaced my TCM with a known working unit and it still happened. So, I'm still stuck at square one. Is there anything else I can check? Or anything I can check while I'm having the problem? Any help is greatly appreciated. I anticipate towing our trailer here in a few months and really don't want to slam into 2nd gear with all the extra weight behind the truck.

Thanks for any info.

diyer2 · January 1, 2016

Has the trans had proper maintenance?

If there is no other reason for this to start happening, meaning there was no other work done so the possibility of a wire or ? being damaged, I would put in a input shaft sensor ($40.00? ) being it trips that code, can't be that expensive. The next would be shift solenoids.

Intermittent problems are a nightmare.

QuickSilverz · January 1, 2016

I replaced as much fluid as I could when I installed a trans cooler. The truck only has 43k miles on it.

I may just replace the sensor, but easier said than done. This sensor is supposedly buried in the transmission a bit.

diyer2 · January 2, 2016

As I get older I don't enjoy wrenching as much but the current shop rates always close the deal, besides I hate to pay for something I can do. If you have a garage good on ya, I don't.