Question re 2005 Chevy Trailblazer transmission shifting into neutral

Hello all: I’m new to this forum but hoping to get some help. We own a 2005 Chevy Trailblazer, 8 cyl, 150K miles. Since July 11, the transmission has been slipping into neutral, usually when slowing down. This happens anywhere, and usually in slow (so far) traffic. My husband has been able to get the car to drive either in D3, or has been able to get it back into Drive, and the car just drives off like nothing happened. This usually takes a few minutes of turning it off and on, and shifting gears. Today he drove it in AWD, and it was fine (so far). He normally drives it in 4WD. It has been at the Chevy shop twice; $1,500 later, they have been unable to duplicate this problem and, because there aren’t any codes, cannot tell us what’s going on. Needless to say, I’ve had it. Any ideas from this forum would be welcome and appreciated!!!

Meant to say he normally drives it in 2 wheel drive. thanks.

If you hang around the Trailblazer specific forums online, you will see a common warning to change the transmission fluid at least every 50k miles to avoid problems. When was the last time it was done on your truck?

What have you spend $1500 on? You must have some more info to give - ? What is the service history of the transmission?

I assume that the “Chevy shop” is a dealer? Not all dealer service departments will have people who are good with transmissions. I’d rather have it at a local transmission shop.

Is leaving it in 4WD normal? I confess that the last time I drove a 4WD vehicle regularly everything was manual - no electronics at all. But even so a 4WD setting for everyday driving doesn’t sound right.

“It has been at the Chevy shop twice; $1,500 later, they have been unable to duplicate this problem and, because there aren’t any codes, cannot tell us what’s going on.”

If they couldn’t duplicate the problem just what did they charge you $1500 for. That is a bit steep for not diagnosing anything.

This is one for Transman. Where is he anyway.

I had a similar problem with my Riviera only it would go to neutral when shifting from 1st to 2nd only on rare occassions but unpredictable. Usually when hot outside. Shop that overhauled it previously didn’t know what the problem was either. Seems to me there was some issue with a valve tube wearing or something causing a valve to stick. I ended up junking mine without ever determining the cause.

Here’s more info; the $1,500 was from two repairs; the first time the “shift into neutral” happened (around July 11), the advisor at the Chevy dealer shop told him that they couldn’t find anything, and to drive the car until the problem got worse. A couple of days later, the check engine light came on. Code was P0300, for “engine misfire.” Basically, they performed an 8-cyl tune-up for $1123. Car was fine until three days later, we got in the car to go to work, and the gear stuck in reverse. Turned car off, wouldn’t turn back on, and wouldn’t change gears. Towed to shop, $434 later, the shift cable was replaced. A few days later, car shifted into neutral again, two times in one day. Took it back to the same shop, the had a “transmission expert” drive the car for a bit but he was unable to duplicate the problem, of course. Last transmission flush was June 2010. My husband drove it in 4WD for a day, now has it back to 2Hi. So far it’s been fine, but I don’t trust it. May take it to an Amoco shop, but we’ve both heard not good stuff about them, so not sure what to do. Car has been driving fine, so far.

Ok - well that helps. So far you’ve spent $0 on the neutraling problem. I have no idea how they managed to ratchet things up to $1123 on a “tune up” - you really need to stop using a dealer - but a misfire code followed by a tune up has nothing to do with a neutraling transmission.

You could list out what was involved in the tune up, but I wouldn’t include any of that in any kind if vehicle “repair” cost. That stuff is maintenance & if it got to the point of misfiring then you were probably overdue to spend it anyway.

It is also entirely unlikely that the shift cable has anything to do with the neutraling.

On that note, rather than saying that the transmission is slipping into neutral describe exactly what the vehicle does - your actions, sights, sounds, feels of the vehicle… People give different labels to the odd things that an automatic transmission might do and then it all just gets confused.

You’re correct to shy away from AAMCO. Ask around among people that you know for a locally owned transmission shop.

From what you are describing, your problem internal and NOT electronic related. It sounds as though you are losing the forward clutch assy for some reason. Pump related?? Most likely, not sure though unless I was able to drive it and actually see it happen, thats why the dealer has’nt been much help yet.


I appreciate everyone’s input! And no, I am not crazy about that Chevy shop - it IS a dealer shop and we have had other experiences with them, that I won’t go into here, that have shown me that it is not very well run. Just haven’t found a good repair place yet for this car. Here is a description of what happens; either we are going up a slight hill slowly, or moving in traffic slowly, and the car goes “thunk,” kind of jumps forward, and is no longer in Drive; I say that it “shifts into neutral” but not even sure if that is an accurate description. It’s just no longer in Drive. So, my husband fiddles with it until he gets it to drive - by either putting it in D3, or AWD; so far, that seems to have worked. Thanks for input re aamco (forgot that’s how its spelled) - we won’t take it there.

I would post your detailed problem description over here-

Be very specific about the sequence of events and what has been done/tried so far. You can cut and paste from these pages if necessary but the more thorough you are, the better information you’ll get.

If you do go post it again keep a distinction in your mind between what the transmission is doing and what the gear selector says. A transmission itself really isn’t in or out of “Drive.” You select Drive with the gear shifter and then this activates the transmission’s forward gears - yours probably has 1st to 4th gear. When you talk about the transmission jolting and no longer being in Drive it suggests your gear selector is actually moving itself to the Neutral position. (Is it?)

I am assuming that you are “moving in traffic slowly” with the gear selector in “D.” At this point your transmission is probably in first or second gear. Then there is a jolt of some kind and the gear selector remains in “D” but when you press the gas the truck acts as if it is in neutral. At that point it would have dropped out of whatever gear it is in. If all of that is true I’d be shocked if the transmission didn’t need to be opened up - i.e. overhauled (as Transman noted above).