Possible Transmission Problem? [Archive] - Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum

: Possible Transmission Problem?

01-01-2009, 09:04 PM
Happy New Year everyone,

I own a 2005 Chevy Trailblazer LT Automatic Trans with about 37,000 miles and just went over my 3yr/36,000 mile warranty in August. Last week I drove about 2 hours (highway) to pick up my daughter for Christmas. I noticed a slight shudder around 65mph seeming to come from the front axle area. I just blew it off but I slowed down due to traffic congestion a little later and felt another shudder around the same speed. So now it has my full and undivided attention. So I start playing around with driving speeds watching my TAC closely. I slow to about 55 mph and notice the TAC jump up & down from 1500rpm to 1800 rpm. It is not constant but happens every 10 seconds or so. There is no noise or shudder while this is going on. I am a pretty positive I am in OD (1400-1500rpm @ 55 mph) so I slowly apply the gas and feel another light shudder and a small thud. At this point, I continue to make sure I can duplicate the problem which I can. So I speed back up to about 65 mph around 1800rpm, steady the pace, then lightly apply gas and I get the shudder for about 2 to 3 secs.

(The shudder is the only word that comes to mind to describe the problem. If I had to explain it another way I would say the shudder feels like the entire front axle shakes or bounces. The thud can be described as a hard shift I suppose.)

Well tonight, we went out for dinner and I decided to test this issue again. I am able to duplicate the exact same problem using the same methods above but this time the thuds are a little sharper and the shudder is a little heavier. I have no problems getting to 55mph and seems to shift smoothly. I checked the trans fluid tonight and it was full. Fluid color was clear bright red
with no noticable shiny fragments or debris.


01-02-2009, 01:11 AM
:tiphat Welcome :tiphat Do you have the selector switch in 2WD or A4WD? I had a shudder/stutter that went away when switched from A4WD to 2WD. Changed the transfer case fluid and the problem is gone. :m2: It will help us if you fill in your User CP info at the top of the page.

01-02-2009, 07:43 PM
Sorry for the delayed response. Had to drive my daughter back to VA today with my wife's car.

Sorry about the USER CP info....it is filled in now. The selector switch is in 2WD. I switched it to A4WD and got up to the same speed. Had the exact same problem. Once I parked I was able to switch from 2WD, A4WD, 4HI, & 4LOW without any problems.

01-03-2009, 12:47 AM
If the tach reading is jumping up and down, I'm thinking maybe the transmission lock-up is going in and out. Anyone else have an idea?

01-03-2009, 07:55 PM
If the tach reading is jumping up and down, I'm thinking maybe the transmission lock-up is going in and out. Anyone else have an idea?
:iagree: That is what it sounds like to me. Does it do this if you lock the trans in 3rd?

01-03-2009, 11:15 PM
Not at all

01-04-2009, 02:36 AM
Did you notice a harsh 1-2 shift or have your MIL come on? Mine did the same as yours at 65 the other day. Mine threw a p0894 code. I cleared it and it hasn't done it again, but I haven't done much highway driving.

01-04-2009, 06:14 AM
3yr/36k is the bumper to bumper warranty. drivetrain warranty is 6yr/60k if im not mistaken. check with your dealer on that.

01-04-2009, 09:40 AM
No...doesn't shift hard at all getting up to 50-55mph and have not gotten an MIL. What exactly is transmission lock up? So would it be a true statement to say....Get the trans system flushed and test it out again?

Yeah, I have read the warranty book forward, backward, upside down, with a witch doctor....you name it and I still am not sure about my warranty. Those things read like stereo instructions. I found the 3/36,000 part but then it goes into emission control systems and blah blah blah.

01-07-2009, 04:37 PM
I had a similar problem with the rpm's climbing, espically up hill and in 3rd and 4th gear. Turned out the tranny was severly losing pressure in 3rd and 4th and had to be rebuilt. Granted it happened at 112K, so $1700 for a rebuilt transmission seemed decent. I had the PCM for less tune and shift firmness 3 but only from 95K on. I'm sure the tranny was on its way out before that. I plan on keeping the the tune with the rebuilt tranny. Good luck, seems early for your transmission to be slipping, but keep an eye on it. Good ol 4L60E...

02-03-2009, 10:04 PM
Ok I have an 03 and it started doing the same thing exactly as the starter of the post and did it for a few hundred miles. Last weekend I drove from to Columbus Ohio to Alabama and at Nashville I got off the interstate and at the stop light I noticed a whirring noise and when the light turned green and I started to move the noise was louder and it slipped a bunch and got worse as I pulled to the Autozone. Fluid was slightly grey-pink and up to level. I pumped out a quart and put in Trans-X but no change. If I let it cool a while it would move well for a few minutes and be quiet, but then noise and slip again. I actually got it the last 100 miles to the house after I let it cool for an hour. Bought another TB and towed this one back to OH with transfer case in neutral and now with it so cold up here the thing will drive for about 4 miles with no noise or slip before it starts slipping again and seems like as many times as I let it cool down it will move again for a while. Is trans ok then and maybe just a bad torque convertor or pump or both ???????

02-04-2009, 03:29 PM
I'm absolutely no expert here like some of you but my story is a little similar to WolfCP except I have 123K on my Blazer (second owner).

I was passing a truck when I noticed my rpm's around 4 to 5K and when I got back in the right lane it didn't get any better. Cause was diagnosed as a loss of 3rd and 4th gears. I was quoted by a number of shops for a rebuild at somewhere between $1900-$2500 "depending on what went wrong".

I did a lot of research and found Trans-Plant Transmissions out of Mesa, AZ to have great prices and a 1 yr warranty ($725 with a rebuilt transfer case and shipping). They also found a shop for me that would install it for $500 including back flushing and fluids. Core deposit was only $325 an Vincent at Trans-Plant told not to worry as they rarely ever fail to return the deposit.

The shop called me yesterday and to tell me it was in and to bring it down on Friday for the swap. It will take about 4 hours "book time" so I get it back the same day! I figure I've saved at least 1/3 to 1/2 the price.

I'll let you know how this all goes but so far I'm feeling good about it.

02-04-2009, 04:01 PM
Hey Wolvescp >>> Did you get the problem worked out???

02-24-2009, 07:50 PM
Sure didn't. I went to the shop and had them flush the transmission then drove it down to VA from home (NJ). Still the same problem. Between 40-70mph is where the front axle shakes or thumps usually at the low end of the RPMs but I think it goes into OD way too early. In some cases, it feels like it shifts into OD at 40 mph and check the RPM which is sitting at 1400-1500. That is when it really starts to act up. I can step on the gas to get out of OD and I don't notice anything to get it up to 70mph. Once I get it 70mph (RPM 2000) it works like a champ. No problems at all.

I am going to take it into the shop this week. Enough tinkering with it before I get stuck somewhere. Will keep you guys updated.

03-07-2009, 08:56 PM
Well...dealer couldn't find anything wrong!:hissy: I asked him to keep it overnight and try again in the morning. Still nothing. So I asked them to flush the system (again). I haven't had any problems since then (last week). Hmmmm...I have a 2010 Camaro on order and am selling the wife's '03 Jeep Grand Cherokee. Boy, I really hope this thing doesn't screw up on me.

08-18-2009, 10:31 PM
Wolvescp, did you ever find out what is wrong? I have a 2004 TB now doing the same thing.

08-19-2009, 12:47 AM
Nope....it has not happened in months. I had the system flushed 3 times I think. After the last flush it was fine and has run fine ever since.:weird:

12-16-2010, 09:15 PM
Hi Everyone, Not only am I new to this site, I am new to forums of any kind. My mechanic is on several and swears by them. So, if I don't seem like I know my way around its b/c I don't. I've decided to join in an effort to find out what in the world my truck is doing. It has the same problem that is already listed with the skipping, thumping, jumping, whatever you want to refer to it as around 60mph in OD. My truck has 147k on it and has been great. This is my 2nd trailblazer. Didn't have 1st one long. I bought it new and have stayed on top of all recommended services and then some. Fluid was just recently changed, new thermostat, and throttle body due to SES light. I originally though the truck had a dead miss, but with the recent repairs, plugs, and boots the motor seems to be running great. Torque converter lock up is what it seems like, but I'm a landscaper. Any help out there?
Thanks, Allscapes

12-17-2010, 12:02 AM
The 4L60E transmission was known to sometimes have torque converter lockup issues. The 4L60E in my 98 Camaro was really bad about it, once the transmission warmed up the lockup wouldn't happen at all. Bye bye fuel economy and hello hot transmission.

What I did to fix that on my Camaro was install the Transgo SK-4L60E kit. It replaced the TCC lockup valve, and upgraded a few springs and stuff inside the valve body. After that, I never had any more TCC lockup problems. That trans has 161k on it, and zero issues. Well, except the car it is in is now wrecked...

Last month I put the same kit in my Trailblazer (along with a couple other upgrades I have learned about since doing the trans in the Camaro, such as Sonnax pistons and the vette servo). It wasn't having any issues but I figured it's the same darn transmission, it's very possible for it to have the same darn issue later, so why not take care of it while I was doing the trans cooler lines and fluid change?

All that is to say, if it is a torque converter lockup issue, the Transgo SK-4L60E kit might be the fix for you.

12-17-2010, 11:50 AM
I'm having similar problems. After throwing a P0014 code, the cam sensor and actuator were changed out, but I'm still having sluggish shifts.

I've read here about the Transgo 4L60E kit. Is this a fix that can be done without pulling the trans? Also read about a TC kit, same question.

12-17-2010, 12:20 PM
I'm having similar problems. After throwing a P0014 code, the cam sensor and actuator were changed out, but I'm still having sluggish shifts.

I've read here about the Transgo 4L60E kit. Is this a fix that can be done without pulling the trans? Also read about a TC kit, same question.

Yes. You just have to get underneath the truck and drop the pan to get to the valve body. To do any spring upgrades to the 2-4 servo (or upgrade the servo itself) you'd need to lower the transmission crossmember a couple inches to get to it. But no removal of the transmission itself necessary. A lift is very helpful.

To save yourself any headaches however, I would also recommend getting the transgo separator plates (make sure you get the right year!). The original plate seals tend to tear. Ask me how I found this out the first time, the hard way :bonk:

12-18-2010, 10:06 AM
Thanks for the reply Sparkyjjo. I am going to get this info to my mechanic. I am still trying to figure out how to get back to my original post and continue the "thread?" For now this is the only way I know how to post. Sorry. Again, I am a landscaper, so I'm much better at grading and patios than I am computers. It sounds like I'm not the only one with tranny issues out of the trailblazer. I didn't realize that the tranny was a 4L60E. I have one in my '94GMC Z71 that I have rebuilt, replaced, re-cussed 3 times now. However, I love that truck and will never get rid of it. 250k and counting, and still doesn't really burn any oil. Good ol' 350cid. They should put them in everything that has an engine:) Anyway, sounds like if the recommended mods are made then the whole tranny should get a run thru. YE-HAH, exactly what you want at christmas time right?!
Thanks, Allscapes

12-18-2010, 03:38 PM
I apologize for an apparent hijacking of your thread, but I saw something here that might have been overlooked and time was getting tight. The Envoy was in the shop going on it's third week. And this did help. Again, sorry about that.

08-30-2012, 06:43 PM
so i have leakage on the passanger side of my chevy trailblazer i was told it could be a hole in one of my cooling lines. when this problem first happened i drove home but i couldnt pick up any speed will this leakage cause my suv to move slowly :worried:

11-06-2012, 01:37 AM
Hi. I have an 03 TB LT 4x4. the same thing happened to me about a month and a half ago. while on the hwy i noticed that my RPMs started to jump up and down by 500 every few seconds. progressively got worse. and my mpg went from 19.5 in town to 12.1. come to find out it was my torque converter lock out. last week i hit the highway to head to work and everything seemed fine. pulling on it shifted from 1st to 2nd with no issues, then came 3rd. instead of shifting to 3rd it just red lined. i lost 3rd and 4th. wound up having the tranny rebuilt the next day. was 1400 for the full rebuild. runs like new now.