Transmission Issue?

dlcj21 · July 31, 2014

Hi,

I recently started having a problem with my 2007 Silverado LTZ.

The issue, lets say I'm going 35 MPH and then have to slow down but not come to a complete stop, when I accelerate normally (not punching it), the engine RPM revs up very high and it will not shift to the next gear. It's an automatic transmission and it normally shifts between 2500 and 3000 RPM. When this issue happens it goes well into the 4000 range which is odd because in the 4 years I've owned it, I've never had it go into that range on normal acceleration. I don't try to press the issue because I don't want to tear up the engine so I slow down to a complete stop put it in park, then back into drive and it is normal again.

It started happening 2.5 weeks ago. It seems to happen every 4 or 5 days. It happened the first time when my dad was driving my truck on 7/13. The way he explained it sounded like he had accidentally put it in 4 wheel drive so I didn't think anything of it. I asked him if it was in 4WD and he said yes, then turned it to 2WD and it didn't happen again for him. It happened to me on 7-17 for the first time. I immediately called the dealership and told them what was going on and they recommended a transmission flush but couldn't get me in until 7-28 to do it. While waiting for my appointment it happens 3 times in one day on 7-22 and then did not happen again until yesterday (7-30).

Thankfully each time it's happened I haven't had any traffic behind me so I could stop put it in park then start again. The times it's happened it's after I slow down or turn a sharp corner then accelerate, never when accelerating from a complete stop.

Long story short is my transmission going out or is it something else?

gmtech4 · August 1, 2014

something else ,take it in to a dealer that has a tranny guy,,,,a flush only empties your wallet ,,,dont feel pressured into one

dlcj21 · August 1, 2014

I'm glad you said it's something else. That at least puts my mind at ease in terms of having to have it rebuilt or replaced.

They didn't pressure me to do the flush, that's what they recommended after I told them what was happening so I did what they recommended.

I was hoping someone else had the same problem present or past that could tell me what they had done to fix it so I could look into cost. I'm already set back $300 doing something that like you said "only emptied my wallet" and didn't fix the problem. I don't want to keep throwing money at stuff that won't fix it since I know nothing about it I have to trust them at their word you know?

I can't make it happen and it doesn't seem to happen but every 4 or 5 days so a test drive won't yield any results unless it's the off chance that it happens while they're in the car with me. They ran the codes because my cruise control and parking assist systems went out and determined that my brake light switch and park assist sensors had went out. If it was throwing any other codes they would have been apparent at the time right? Or do they only runs tests for the systems I reported had problems?

Anyway, I'm still hoping someone can shed some light on it while I look into what chevy dealers around me have a transmission guy.

dlcj21 · October 16, 2014

So it's been happening once a week for the last few months but after I stop, put it in park, then drive and start moving again, it doesn't happen again for like a week. I've had a few people look at it, had the codes ran, and they couldn't find anything and I was tired of throwing money at it so I decided to hold off from doing anything until it happened more frequently.

Randomly my battery died yesterday, my truck wouldn't start, so I got a new battery and it feels like my truck has a lot more get up and go. I'm wondering if my dying battery was causing the electrical system not to have enough power and that was causing issues with the computer that controls the transmission and thus my problem? I don't know but with the new battery, my truck feels like it's brand new and it's shifting a lot sooner than it was before.

I found this interesting tidbit when searching to see if a dead or low battery could cause the problem:

A weak battery or low battery voltage can cause the transmission to enter into fail safe mode. This will cause a loss of power because the transmission will be locked in third gear.

That sounds exactly like what was happening to me. I'll report back if it happens again but just wanted to get this out here in case it helps others who are having the same problem.