Transmission question

[timothy918]

I'm so glad I found where all the great people from the other site went to. Before I realized they had left I posted this.

Hi all, I have a 2004 Trailblazer EXT 4x4 with 145,000 miles, and a 4.2L engine. While driving at around 55-60 mph, it shifts into OD and the Torque converter locks up, but then it seems like the engine sputters like it's got a miss and causes a shudder then the torque converter acts like it doesn't know if it should stay locked up. The tach then fluctuates about 200-300 rpm. After doing some searching it seems the TCC valve may be defective. About 2 years ago the transmission went out and I had a GM Remanufactured transmission installed in Tifton, Georgia (transmission shop) on our way to Florida. I live in Indiana. That's why I went with a GM Reman. Because if there is/was a problem I could take to any GM dealership for warranty work. I had to take it to the GM dealership in Florida 2 days after it was installed because the check engine light came on and it was a transmission code (don't remember what it was). The dealership said they replaced a solenoid inside the valve body. It has a 3 year 100,000 mile warranty. Would this problem be covered under the warranty?
When I take it to the dealership should I tell them I think it's the TCC or just tell them what's it's doing and let them figure it out?

 

[BRomanJr]

I'm so glad I found where all the great people from the other site went to. Before I realized they had left I posted this.

Hi all, I have a 2004 Trailblazer EXT 4x4 with 145,000 miles, and a 4.2L engine. While driving at around 55-60 mph, it shifts into OD and the Torque converter locks up, but then it seems like the engine sputters like it's got a miss and causes a shudder then the torque converter acts like it doesn't know if it should stay locked up. The tach then fluctuates about 200-300 rpm. After doing some searching it seems the TCC valve may be defective. About 2 years ago the transmission went out and I had a GM Remanufactured transmission installed in Tifton, Georgia (transmission shop) on our way to Florida. I live in Indiana. That's why I went with a GM Reman. Because if there is/was a problem I could take to any GM dealership for warranty work. I had to take it to the GM dealership in Florida 2 days after it was installed because the check engine light came on and it was a transmission code (don't remember what it was). The dealership said they replaced a solenoid inside the valve body. It has a 3 year 100,000 mile warranty. Would this problem be covered under the warranty?
When I take it to the dealership should I tell them I think it's the TCC or just tell them what's it's doing and let them figure it out?

It may sound like a broken record to many members on here but the first thing you should do (if you haven't already) is to disconnect the battery, remove the Throttle Body and clean both sides with TB Cleaner then reinstall.

It needs to be cleaned periodically whether it is the current problem or not.

Two caveats:
1)The battery disconnect might trigger spontaneous HVAC Actuator problems.
2)Keep the TB spray out of the Electrical parts on the TB (keep that side high while spraying and scrubbing)

 

[timothy918]

It may sound like a broken record to many members on here but the first thing you should do (if you haven't already) is to disconnect the battery, remove the Throttle Body and clean both sides with TB Cleaner then reinstall.

It needs to be cleaned periodically whether it is the current problem or not.

I am going to take your advice and clean the throttle body because you're right I've read that over and over at the other place it needs to be clean.
How does the throttle body effect the operation of the TCC on the transmission? If I drive in 3rd it doesn't act like it has a miss.

 

[meerschm]

I would just tell them what you saw, and let them figure it out.


be sure to check the fluid level first. my acted something like that , would fall out of lock at low throttle and around 55 MPH, and it was just low on fluid.

can you read any codes?

could also be time for plugs.

 

[timothy918]

I would just tell them what you saw, and let them figure it out.


be sure to check the fluid level first. my acted something like that , would fall out of lock at low throttle and around 55 MPH, and it was just low on fluid.

can you read any codes?

could also be time for plugs.

Plugs are about a year old. Fluid level is good (first thing I checked) No codes.

 

[Wooluf1952]

I would just tell them what you saw, and let them figure it out.QUOTE]

They won't know for sure if it's covered until they check it out. Telling them what you think is wrong could lead them down a wrong path. If they replace that part and it doesn't fix the problem, they can blame it on you.

Also:
Welcome

In case you haven't heard:
http://gmtnation.com/f5/welcome-gmtnation-com-heres-story-226/

 

[dfc739]

If you're having the problem I did, it's extremely common on the 4L60E transmission. It uses pulse width modulation (PWM) to apply the torque converter clutch for a smoother apply (you typically can't even tell it's locking the torque converter unless you're watching gas mileage). This rapid back and forth causes the valve to wear in the valve body and start leaking around it. Mine would only keep the torque converter locked if I feathered the accelerator. If I was cruising on the highway and had to go up even a very slight incline it would drop converter lock (and gas mileage) then relock once I got over the small hill. This lock-unlock wears out the torque converter clutch faster also. See this:

30 Common 4L60E Transmission Problems & Repair | Charlotte NC

Your problem sounds like #25. There are numerous fixes out there for this problem. I used a Transgo shift correction kit to replace the TCC valve and more but Superior and Sonnax also make fixes. It bypasses the PWM and makes it feel more like another gear when it engages. I actually like this feeling and it'll keep torque converter lock going up small hills. If it's still under warranty, you should take it back to them but only tell them how it was acting. Make sure it's covered under warranty. Once it wears more and starts slipping, it'll throw a P1870 code. I did a writeup with pics when I did this and changed out several other parts in my valve body:

http://gmtnation.com/f93/how-remove-4l60e-valve-body-replace-plastic-accumulator-pistons-4972/

 

[timothy918]

If you're having the problem I did, it's extremely common on the 4L60E transmission. It uses pulse width modulation (PWM) to apply the torque converter clutch for a smoother apply (you typically can't even tell it's locking the torque converter unless you're watching gas mileage). This rapid back and forth causes the valve to wear in the valve body and start leaking around it. Mine would only keep the torque converter locked if I feathered the accelerator. If I was cruising on the highway and had to go up even a very slight incline it would drop converter lock (and gas mileage) then relock once I got over the small hill. This lock-unlock wears out the torque converter clutch faster also. See this:

30 Common 4L60E Transmission Problems & Repair | Charlotte NC

Your problem sounds like #25. There are numerous fixes out there for this problem. I used a Transgo shift correction kit to replace the TCC valve and more but Superior and Sonnax also make fixes. It bypasses the PWM and makes it feel more like another gear when it engages. I actually like this feeling and it'll keep torque converter lock going up small hills. If it's still under warranty, you should take it back to them but only tell them how it was acting. Make sure it's covered under warranty. Once it wears more and starts slipping, it'll throw a P1870 code. I did a writeup with pics when I did this and changed out several other parts in my valve body:

http://gmtnation.com/f93/how-remove-4l60e-valve-body-replace-plastic-accumulator-pistons-4972/

Thanks for the great information. I bought the GM remanufactured transmission with a 3 year 100,000 mile warranty through GM which is up in July. I'm not even close to the mileage part of the warranty. Do you think they're gonna give me any problems because its not throwing any codes? And what if they come back and say they can't find anything wrong with it? Thanks again for the info.

 

[gmcman]

I'm going through a similar issue as well and noticed a shudder while towing a couple weekends ago. Did the same thing you described and when I was accelerating at about 55-60 there was a slight vibration and went away when I let off the gas.

I actually have the Transgo replacement valve kit on my table awaiting next weekend for the swap.

One thing you can try is when the TC is locked and is shuddering, lightly tap the brake pedal which will disengage the TCC but stay on the gas while you do this. If the shudder disappears then the valve is likely the problem. The Transgo kit also includes a drill bit to ream the opening of the separator plate to increase clutch holding pressure in the TCC.

I have heard that the clutch in our TC is made up of carbon fiber and Kevlar clutch material and last a very long time if everything works as it should.

I would surely try the warranty first but if you need to open the bottom of the trans and you are slightly mechanically inclined....you can easily fresehen up the valve body by replacing the separator plate, a few accumulator pistons, and a vette servo which will make a world of difference.

 

[timothy918]

Update to my transmission problem. I took it to the dealership and they did a diagnostic and found I was getting random misfires on cylinders #1 and #5. They told me the transmission pressures were fine and before anything else can be done the misfires need to be fixed. This cost me $80 for the diagnostic and $70 for 2 days of rental car. I changes all 6 plugs and cleaned the throttle body now according to my obd reader the misfires are now zero. Now the shuddering when the torque converter locks up is pretty much gone. Now the problem is when you're accelerating and the trans switches from 1st to 2nd it hits very hard like its got a shift kit and when the trans switches from 2nd to 3rd it acts like you're putting it in neutral and them back into drive. The tach goes up at least a 1000 rpms before 3rd gear engages and every once in awhile when you put it in reverse it will die. Is there anything I check before I take it back to dealer. Thanks for the help.

 

[gmcman]

Now the problem is when you're accelerating and the trans switches from 1st to 2nd it hits very hard like its got a shift kit and when the trans switches from 2nd to 3rd it acts like you're putting it in neutral and them back into drive. The tach goes up at least a 1000 rpms before 3rd gear engages and every once in awhile when you put it in reverse it will die. Is there anything I check before I take it back to dealer. Thanks for the help.

At 3500 RPM's in 2nd gear I had a flare and it would jump about 300 RPM's, in the video below. Does your's act similar? I needed to change my separator plate since the check balls were pounding through the plate, this fixed the hard 1-2 shift and the vette servo fixed the 2-3 flare but I think the plate fixed that as well, just the servo holds the clutches with more force and also firmed up the shift.

I would take it back if still under warranty and roll the dice. If they won't fix it then changing some parts like I did should fix the issues. Let us know what they say.

This is when I was having slippage in my 2-3 shift last year.

[video=youtube;DV-3M0FmBMI]http://www.youtube.com/watch?v=DV-3M0FmBMI[/video]

 

[timothy918]

At 3500 RPM's in 2nd gear I had a flare and it would jump about 300 RPM's, in the video below. Does your's act similar? I needed to change my separator plate since the check balls were pounding through the plate, this fixed the hard 1-2 shift and the vette servo fixed the 2-3 flare but I think the plate fixed that as well, just the servo holds the clutches with more force and also firmed up the shift.

I would take it back if still under warranty and roll the dice. If they won't fix it then changing some parts like I did should fix the issues. Let us know what they say.

Your video is what my trailblazer is doing. It revs higher when its switching between 2nd and 3rd. I want to take it back to the dealer I just want to know if there's anything else I should check before I take it back so they don't surprise me again. I knew the misfires weren't the problem but they wanted that fixed (trying to make a sale) before they would move forward. I don't have a problem working on it. It's just the point that it's under warranty and they should honor it instead of making jusp through hoops.

 

[gmcman]

Have them ride with you when it flares. Tell them the trans is slipping or (flaring) on the 2-3 shift. Have you kept up on the fluid changes? That would be just for the warranty if they ask. Go in there with some knowledge so they don't try to push it off to the end of the warranty.

One of the ways a trans works is if the pump is good which has already been determined it is, and the pressure has been noted...you need pressure to move the valves. The pressure is always there but is it moving the valve. Equal pressure on both sides of the valve keeps it in the middle, lower pressure on one side allows it to move. If you have pressure bleeding somewhere then a valve may not fully seat and then you get slippage from a less than fully applied clutch pack.

Of course there are many other variables but the point of my ramblings is under normal maintenance and no abuse you should not be experiencing this at your current mileage on the reman trans.

 

[timothy918]

Another update to my transmission problem. I haven't taken it back to the dealer yet. It's going back Monday because now I'm getting P0756 code and it doesn't want to accelerate from a stop, once you get going it goes. I suspect the trans isn't downshifting back to first. I checked the trans dipstick and it showing full but if you look closely you can see metal specks.

At what mileage does the GM remanufactured transmission need to be serviced?

 

[gmcman]

Another update to my transmission problem. I haven't taken it back to the dealer yet. It's going back Monday because now I'm getting P0756 code and it doesn't want to accelerate from a stop, once you get going it goes. I suspect the trans isn't downshifting back to first. I checked the trans dipstick and it showing full but if you look closely you can see metal specks.

At what mileage does the GM remanufactured transmission need to be serviced?

I would stop driving it before it leaves you stranded.

This is what's likely happening and what you need to do. First you need to find out about the warranty, and what the dealer, or whoever is going to service the trans under warranty will cover.

The metal flakes are bad. This will likely restrict flow through the filter and ruin other areas of the trans, including the valve body. The code is for the shift solenoid and is an easily repaired part. Remove the pan and both are side by side and are removed by a spring clip.

Does the vehicle move from a stop if you select 2nd gear? This puts the trans in 2nd from a standstill.

The fact the shift solenoid could be bad is obviously possible but why the flakes? This is generally from burning clutches so who knows how much is circulating through the trans.

I believe the flush, replace separator plate, TCC eliminator and accumulator pistons will be on the back burner for now until you find out what the shop says.

I will play the devil card and say they might not want to replace the trans and try to push it off until the warranty expires. Just keep that thought in mind if the deal starts to turn south for you.

Good luck , keep us posted.

 

[timothy918]

I would stop driving it before it leaves you stranded.

This is what's likely happening and what you need to do. First you need to find out about the warranty, and what the dealer, or whoever is going to service the trans under warranty will cover.

The metal flakes are bad. This will likely restrict flow through the filter and ruin other areas of the trans, including the valve body. The code is for the shift solenoid and is an easily repaired part. Remove the pan and both are side by side and are removed by a spring clip.

Does the vehicle move from a stop if you select 2nd gear? This puts the trans in 2nd from a standstill.

The fact the shift solenoid could be bad is obviously possible but why the flakes? This is generally from burning clutches so who knows how much is circulating through the trans.

I believe the flush, replace separator plate, TCC eliminator and accumulator pistons will be on the back burner for now until you find out what the shop says.

I will play the devil card and say they might not want to replace the trans and try to push it off until the warranty expires. Just keep that thought in mind if the deal starts to turn south for you.

Good luck , keep us posted.

The trans is a GM remanufactured transmission it has a 3yr 100,000 mile warranty which is up in June. So I know what to watch for in what ways can they push fixing it until the warranty expires?
The metal flakes are really really small. You have to look at the dipstick real close to see them.
The trans was installed at 96,500 miles I now have 135,500 miles. Should the trans had any scheduled services done in the 36,000 mile time frame?

 

[gmcman]

Should the trans had any scheduled services done in the 36,000 mile time frame?

The way I understand it is the warranty requires you to follow the maintenance schedule in your owners manual.

For the automatic transmission the service intervals are at 50K, 100K, 150K etc. The footnotes for this schedule show that the 50K intervals are for severe duty and one of those footnotes includes:

Change automatic transmission fluid and filter if the
vehicle is mainly driven under one or more of these
conditions:

In heavy city traffic where the outside temperature
regularly reaches 90°F (32°C) or higher.

This can sometimes be used against you but fortunately in your case you are only at the 40K mark. Indiana doesn't get too hot but mileage is key here.

 

[timothy918]

The way I understand it is the warranty requires you to follow the maintenance schedule in your owners manual.

For the automatic transmission the service intervals are at 50K, 100K, 150K etc. The footnotes for this schedule show that the 50K intervals are for severe duty and one of those footnotes includes:

Change automatic transmission fluid and filter if the
vehicle is mainly driven under one or more of these
conditions:

In heavy city traffic where the outside temperature
regularly reaches 90°F (32°C) or higher.

This can sometimes be used against you but fortunately in your case you are only at the 40K mark. Indiana doesn't get too hot but mileage is key here.

Thank you. That was the information I was looking for. Just one less thing they can mess with me with. It's going to the dealer Monday.
I'll keep everybody updated.

 

[CaptainXL]

The metal flakes are really really small. You have to look at the dipstick real close to see them.

If you have metal flakes in the oil then that's bad. The filter should handle anything you would ever see with the naked eye. I would have it serviced under warranty. Also, some transmission shops want you to come back in 5000 miles to check for leaks and change the fluid. It is sometimes a condition of the warranty. Might want to check that.

 

[timothy918]

Finally got the trailblazer to the dealership. The tech called and told me the front pump was in the process of self destructing. Thats why there was metal on the dipstick. He said there were bigger pieces on the magnet in the pan.

They are going to replace the transmission at no charge and extend the warranty another 12 months with unlimited mileage. They also supplied us with a loaner car because I bitched about the first time I brought it in and they wouldn't troubleshoot the transmission because the engine had misfires on 2 cylinders.
I should have it back on Monday.

Thanks everybody that commented.

 

[dfc739]

Finally got the trailblazer to the dealership. The tech called and told me the front pump was in the process of self destructing. Thats why there was metal on the dipstick. He said there were bigger pieces on the magnet in the pan.

They are going to replace the transmission at no charge and extend the warranty another 12 months with unlimited mileage. They also supplied us with a loaner car because I bitched about the first time I brought it in and they wouldn't troubleshoot the transmission because the engine had misfires on 2 cylinders.
I should have it back on Monday.

Thanks everybody that commented.

That makes sense. It's good to know customer service at GM isn't quite dead. Good job!