2003 TrailBlazer Transmission Issue

[Blackbeard]

Hey guys, I've got an 03' TrailBlazer with 203k on it and the transmission either shit the bed or is acting up on me. Last night I pulled in, put the vehicle in park and waited for my passenger and as I put it into reverse, it stalled. I started it back up and went to reverse out again and when I gassed it all she did was rev the engine up. No clunking, no grinding, no codes. I managed to get it to back up after a little fussing with the shifter but a few moments later drive stopped working in the middle of the street. No gears would drive the vehicle.
If you start the vehicle from sitting for a while reverse and drive work fine, but after a few moments it degrades. Any ideas?

 

[triz]

someone posted about something similar in a thread. I believe the shop told them they needed a new transmission.

 

[Blackbeard]

Good news everyone!
Clogged filter was the issue. The old fluid was as black as used motor oil! She drives like a dream now except one issue. It won't shift into 3rd or 4th gear. Not sure what could do that but we'll figure it out!

 

[Mooseman]

If it was that neglected, it could be borked. Darkest I have ever seen tranny fluid is a light brown. Black maybe just in the bottom of the pan, which is normal.

 

[The_Roadie]

Is this a new vehicle to you? The standard recommendation is to change all (100%) of the fluids when you first buy a used one. The dipstick should also have been a clue during the pre-purchase inspection, to make sure you pay a fair price.

 

[Blackbeard]

Alright sorry for all the late replies but here's what I've found!

3rd IS still there but does not engage/actually push the vehicle unless you're under 35-30 mph and by the time you get the vehicle to 5.5k - 6k RPM you're only doing about 40-45 mph and it wont shift out of 3rd into 4th! I think the throttle position sensor might be messed up but who knows. Any ideas?

 

[IllogicTC]

Alright sorry for all the late replies but here's what I've found!

3rd IS still there but does not engage/actually push the vehicle unless you're under 35-30 mph and by the time you get the vehicle to 5.5k - 6k RPM you're only doing about 40-45 mph and it wont shift out of 3rd into 4th! I think the throttle position sensor might be messed up but who knows. Any ideas?

The PCM monitors two independently-operating sensors to check for TPS accuracy and commanded vs actual position. Any anomalies in this area would turn on the Reduced Engine Power light, and you wouldn't be able to go very fast. This is a failsafe mode to mitigate the possibility of a runaway vehicle. The throttle position is actuated electronically, rather than mechanically, so to determine what gear and how much gas to give it, the PCM relies on the APPS on the gas pedal, and will adjust the throttle blade accordingly.

There are also DTCs available to identify failure of the APPS, which also uses two independent sensor circuits.

My guess is, with the symptoms and with the old fluid coloration, that transmission either needs rebuilt or outright junked. Did you only recently get this vehicle, or is this something you've had a while? If this thing is new to you, I would have saved a sample of the old fluid and walked right back to the seller and tried negotiating for them to foot all or part of the bill. If not, Yelp and word-of-mouth can keep others from going to the same place. Don't have to yell and scream, just put your position firmly and follow through on it.

 

[Blackbeard]

The PCM monitors two independently-operating sensors to check for TPS accuracy and commanded vs actual position. Any anomalies in this area would turn on the Reduced Engine Power light, and you wouldn't be able to go very fast. This is a failsafe mode to mitigate the possibility of a runaway vehicle. The throttle position is actuated electronically, rather than mechanically, so to determine what gear and how much gas to give it, the PCM relies on the APPS on the gas pedal, and will adjust the throttle blade accordingly.

There are also DTCs available to identify failure of the APPS, which also uses two independent sensor circuits.

My guess is, with the symptoms and with the old fluid coloration, that transmission either needs rebuilt or outright junked. Did you only recently get this vehicle, or is this something you've had a while? If this thing is new to you, I would have saved a sample of the old fluid and walked right back to the seller and tried negotiating for them to foot all or part of the bill. If not, Yelp and word-of-mouth can keep others from going to the same place. Don't have to yell and scream, just put your position firmly and follow through on it.

I was given the vehicle by a neighbor only a few houses down from me, he just wanted to get rid of the vehicle due to the fact it was becoming a money hole for him and I've got no problem fixing problems because most of the parts are relatively cheap anyways. I doubt the transmission is junk because the transmission worked perfectly fine up until the vehicle stalled while in reverse. That's when the transmission didn't work at all and wouldn't move until we changed the fluid and filter. Once we did that we had R-1-2 all perfectly fine with no issues but 3rd only works at a low speed and 4th isn't found yet because 3rd never gets the vehicle fast enough to shift anyways.

 

[IllogicTC]

I was given the vehicle by a neighbor only a few houses down from me, he just wanted to get rid of the vehicle due to the fact it was becoming a money hole for him and I've got no problem fixing problems because most of the parts are relatively cheap anyways. I doubt the transmission is junk because the transmission worked perfectly fine up until the vehicle stalled while in reverse. That's when the transmission didn't work at all and wouldn't move until we changed the fluid and filter. Once we did that we had R-1-2 all perfectly fine with no issues but 3rd only works at a low speed and 4th isn't found yet because 3rd never gets the vehicle fast enough to shift anyways.

The automatic transmission has a lot of components, and a partial failure in one area could keep certain features from functioning while retaining other functions. Clutch packs could make it difficult or impossible to hit certain gears, and if the valve body got clogged up somewhere it could be withholding proper shifts. The transmission is electronically-shifted while in Drive, so the PCM decides when to make the switch to the next gear. The fact that you have to get the tach up high to even get a shift to 3rd (when the PCM has likely commanded shifting long before) is a huge warning sign. 4th should be hit by 40 MPH tops (as that's when the TCC is willing to lock up, 4th can actually be shifted into below that speed)

Black, burnt fluid is a classic sign of burnt-up clutch packs.

 

[Mooseman]

If the truck was given to you free, you're already ahead of the game even if you have to replace the tranny if the rest of the truck is in good condition. Maybe a used one is an option if you're trying to go the less expensive route. Check with yards that will give a warranty and install it where they would also foot the bill if it does fail and needs to be replaced again.

Just an idea.

 

[Blackbeard]

If the truck was given to you free, you're already ahead of the game even if you have to replace the tranny if the rest of the truck is in good condition. Maybe a used one is an option if you're trying to go the less expensive route. Check with yards that will give a warranty and install it where they would also foot the bill if it does fail and needs to be replaced again.

Just an idea.

Yeah I've been looking at local yards and nobody want to touch the transmission. Everyone around here treats the thing like the plague except the local dealership but they want 2k to install + 800 for a new tranny.

 

[IllogicTC]

That's weird, I thought the 4-digit number would be on the new transmission.

The 4L60E has a particular reputation. Not necessarily garbage, but not considered exactly high-quality either, you know?

 

[Blackbeard]

Is there any possibility that this isn't a bad transmission. I'm only 17 and don't have 3k to go blow on a new tranny. I'd really like to fix it rather than replace it.

 

[The_Roadie]

The condition of the fluid guarantees it's the tranny. Find a competent independent mechanic, shun the dealer, or get ready to buy a manual and learn to change it yourself with a used one from eBay or a junkyard.

 

[Mooseman]

I agree. A dead gear or gears usually spells the death of the tranny. Either replace it or scrap it and find an old Accord.

 

[IllogicTC]

Trust me, I don't like being the guy who is bluntly saying, "this is a thousand-dollar issue," but I'd rather tell you straight-up than give you any hopes (and end up blowing money) on things that are not actually the problem.

 

[marinegrunt]

Maybe check the shift solenoids. My Sierra has the 4l60e. When changing the fluid and filter I bumped the 3-4 solenoid without knowing. Got it all back together and it wouldn't shift above 2nd gear. Being that yours is shifting into 3rd on occasion, and that the fluid was as bad as you say, it wouldn't surprise me if you needed a new tranny.

I rebuilt my first tranny a couple years ago. It wasn't the 4l60e but rather the 4t65e. I purchased a rebuild manual online for about $20. Believe it or not it wasn't all that bad of a job. It was our 3rd vehicle so I wasn't in any rush though. I just took my time and really did my research along the way. I also took about 1000 pictures (no kidding) along with labeling everything. It was a lot of fun.