Bravada AWD driveline clunk [Archive] - Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum

: Bravada AWD driveline clunk


03PoloBravada
12-10-2005, 06:33 PM
Well I know this is a TB and Envoy forum but the Bravada is the same ride. I have a driveline clunk that doesnt always happen but it bothers me. It seems to be most common when the vehicle is warmed up, and I am going up a hill. The clunk can be felt in the floor of the vehicle and also in the sterring wheel. A friend of mine has felt the clunk and has described it as feeling like the front wheels were squares. Dealer has driven vehicle several times but the problem can not be recreated for them. Anyone here have any issuse with a cluncking action? Any Rainer owners here?....thoes are copies of the Bravada and they use the same AWD system.

Thanks for any replies

Blulytes
12-10-2005, 09:26 PM
Welcome... This forum actually covers all of the vehicles on our platform... its all in the family... no worries!
Is the clunk happening from first to second gear????
Do you think its more transmission or drive line????

There are other bravada owners around so I'm sure someone else will chime in. But in the mean time, if there is anything else we can help you out with...
let us know!

03PoloBravada
12-10-2005, 10:27 PM
Thanks, Blulytes, its definately not a shifting issue, its more of something not right in the drive line. It just pounds really hard as you are driving, like its hitting potholes or something. I have posted this on other GM forums and noone has any idea what im talking about. I just doont know if its the transfercase, front axle, transmission, i just have no clue.

ScarabEpic22
12-10-2005, 11:44 PM
Welcome to the forums!
Always glad to see another Bavada owner b/c they are extinct, as the Ranier, Saab, and all extended models will be!

Any questions, ask away!

New to TB
12-11-2005, 07:55 AM
How many clunks do you get? Just a couple? Or is it a rapid assault of 15 or 20?

03PoloBravada
12-11-2005, 12:55 PM
Depends, sometimes it is only a few, but most times it can be 15 or 20. This is why I think its something in my AWD system because my friends with trailblazers do not have this problem.

New to TB
12-11-2005, 12:59 PM
Depends, sometimes it is only a few, but most times it can be 15 or 20. This is why I think its something in my AWD system because my friends with trailblazers do not have this problem.
Are you still covered by the B2B warranty?
I would definitely take your car to the dealer, if it's clunking that much it might be doing a lot of damage everytime it's used.

03PoloBravada
12-11-2005, 05:54 PM
Yeah TB its under warrenty, had it at 2 different dealers, neither can get the vehicle to duplicate the problem and neither has ever heard of any problem like this. The best answer I got so far is "we wont know what is wrong until it fails" and I dont like the sound of that answer.

bmm354
12-11-2005, 06:06 PM
Welcome! Sorry to hear about your Bravada's problem. If you can definitely feel it in the steering wheel that points more towards a front axle, front diff, and/or driveshaft issue. I'd think if the system's speed sensors (there are several) or transfer case was causing the problem you'd get the 'Service AWD' light on the dash.

Btw, the Bravada's transfer case and AWD system is actually very similar to what the TB and Envoy have. The Bravada's system works almost as if you glued a TB or Envoy's 4x4 selector switch to A4WD (auto 4WD). It is electronically controlled and is different than the viscous-clutch version the previous generation S10 models had. The newer Bravada uses the same kind of electronic transfer case control module (TCCM) and what's called an encoder motor that the TB and Envoy uses for A4WD.

In fact I've seen some service bulletins for conditions that can occur "in the normal AWD mode for the Bravada and Rainier models, and in the Auto 4WD mode for the TrailBlazer and Envoy." What this means to you is that any shop that has experience with the TB's A4WD system can probably help you out.

New to TB
12-11-2005, 07:12 PM
Yeah TB its under warrenty, had it at 2 different dealers, neither can get the vehicle to duplicate the problem and neither has ever heard of any problem like this. The best answer I got so far is "we wont know what is wrong until it fails" and I dont like the sound of that answer.
I feel your pain, I've been in that position before too. Hopefully it all gets settled before your warranty runs out. Good luck with everything.

03PoloBravada
12-11-2005, 09:29 PM
BMM, do you by chance know any of the service bulletin numbers so I can have something to present to the dealer?

I did have the vehicle serviced when it was new and i think they changed the encoder because it was experiencing the condition of front end binding while turning sharply at slow speeds.

New to TB
12-12-2005, 10:27 PM
Welcome! Sorry to hear about your Bravada's problem. If you can definitely feel it in the steering wheel that points more towards a front axle, front diff, and/or driveshaft issue. I'd think if the system's speed sensors (there are several) or transfer case was causing the problem you'd get the 'Service AWD' light on the dash.

Btw, the Bravada's transfer case and AWD system is actually very similar to what the TB and Envoy have. The Bravada's system works almost as if you glued a TB or Envoy's 4x4 selector switch to A4WD (auto 4WD). It is electronically controlled and is different than the viscous-clutch version the previous generation S10 models had. The newer Bravada uses the same kind of electronic transfer case control module (TCCM) and what's called an encoder motor that the TB and Envoy uses for A4WD.

In fact I've seen some service bulletins for conditions that can occur "in the normal AWD mode for the Bravada and Rainier models, and in the Auto 4WD mode for the TrailBlazer and Envoy." What this means to you is that any shop that has experience with the TB's A4WD system can probably help you out. This is good news.

I've read a lot of people talk about how using A4WD could be harmful to your truck since it will jerk into gear when the rear wheels slip, but if the two sister trucks use it full time it can't be that bad, right?

I've noticed how A4WD can be harsh when it sudden locks in the front wheels, is it like that with the sister trucks with AWD?

03PoloBravada
12-12-2005, 11:49 PM
I never notice it locking into 4wd but I have a Sierra with Auto 4wd and I can feel it slightly in that truck. I just dont understand my harsh clunking I am expercing, my Bravy only has 21,000 miles.

bmm354
12-13-2005, 01:28 PM
BMM, do you by chance know any of the service bulletin numbers so I can have something to present to the dealer?

Here's the list I have for an '03 Bravada, but there are probably more. The DB I have access to seems to only go to sometime in 2004.

#02-04-21-006B Inoperative 4WD/AWD Lamps, Inoperative 4WD/AWD System (Reprogram Transfer Case Control Module) - (Aug 18, 2003)

#03-04-21-005 Service 4WD Light On, 4WD Inoperative, Diagnostic Trouble Codes C0300 and/or C0305 Set (Reprogram Transfer Case Control Module (TCCM)) - (Jun 5, 2003)

#03-04-19-002 Squeak, Squeal or Whistle Noise from Front Axle (Replace Intermediate Axle Seal and/or Differential Carrier Seal) - (Feb 18, 2003)

#02-04-21-008A Shudder, Rocking Motion, Binding, Feels Like Vehicle is Stuck in 4WD (Crow Hop) When Turning at Low Speeds (Replace Transfer Case Encoder Sensor and Reprogram TCCM) - (Feb 13, 2003)

#03-04-17-002 Whine Noise From Rear Axle (Diagnose and Replace Rear Propeller Shaft With New Tuned Torsional Damper Rear Propeller Shaft) - (Feb 12, 2003)

bmm354
12-13-2005, 01:37 PM
I've read a lot of people talk about how using A4WD could be harmful to your truck since it will jerk into gear when the rear wheels slip, but if the two sister trucks use it full time it can't be that bad, right?

I've noticed how A4WD can be harsh when it sudden locks in the front wheels, is it like that with the sister trucks with AWD?

FWIW, on my Envoy there is a slight jerk when it engages the front wheels, but it's not severe enough for me to worry about it. The jerk seems more severe based on how hard I hit the gas. Still, I figure A4WD was tested and designed to engage the way it does, so I wouldn't lose sleep over it.

I also remember reading that if you're in A4WD and the system recognizes it's engaging the front axle too often (meaning you're driving through some seriously sloppy stuff) it will temporarily switch to 4HI mode to avoid unnecessary wear on the system. It will switch back to auto mode by itself. Unfortunately I don't remember where I read this or any more details...

Fishhunter911
12-13-2005, 02:43 PM
here is a dumb question..... do you have the original tires on it??? I had the same problem on my 02 when in A4wd. Front tires were original backs where new when I got it. different diameter made it think it was loosing traffic.

03PoloBravada
12-14-2005, 02:30 PM
Yes the tires are original, size and brand.

#02-04-21-008A Shudder, Rocking Motion, Binding, Feels Like Vehicle is Stuck in 4WD (Crow Hop) When Turning at Low Speeds (Replace Transfer Case Encoder Sensor and Reprogram TCCM) - (Feb 13, 2003)
Thats what I had fixed about 2yeears ago and that problem has been resolved.

I know the A4wd has a slight jerk when it engauges...I have that feature on my Sierra. The Bravy just had this hard pounding, jerking, that can not be correct. I still think it has to be something with the front axle or transfercase to cause this jerking/pounding i feel in the floor and the steering wheel.

This just seems such a hard problem to find.

double10x
12-16-2005, 03:39 PM
If it's a noise/vibration that you note when you're hitting decent sized bumps or potholes, have the dealership replace the Front Stabilizer Bar End links. These End links are almost impossible to know that they are bad when they are. But when they are bad (excessive internal lash), they rattle quite severely with bumps. They almost sound like you have a hammer banging inside the front fenders.

03PoloBravada
12-16-2005, 06:33 PM
The feeling is not from hitting potholes, it feels like hitting potholes in the vehicle while on smooth pavement.

03PoloBravada
01-25-2006, 10:06 PM
It is still clunking, sometimes at speeds over 40mph. I think Im gonna take it to the dealer and request that everything gets changed, T-Case, front axle, hubs. It just shouldnt be doing this. Am I the only one who has this problem?

GroundChuck
01-26-2006, 02:02 PM
03PoloBravada,
Before my current TB I had a Bravada (loved it). I had (I believe) the same issue that you are having. To me it felt like the bumps you feel when hitting the (larger) cracks in the pavement (although as you mentioned, I was on smooth road). It normally happened during acceleration. I took it in the first time and the dealer replaced the whole front end. Problem solved. 10K miles later it came back. Had them look at it again. This that time they tried other things to narrow in on the issue. Just prior to me saying "screw it, replace the whole front end again" my lease was up so I didn't bother with it. I feel your pain, it's a bummer. The only thing that I know that worked was replacing the whole front end.

03PoloBravada
02-09-2006, 11:11 PM
03PoloBravada,
Before my current TB I had a Bravada (loved it). I had (I believe) the same issue that you are having. To me it felt like the bumps you feel when hitting the (larger) cracks in the pavement (although as you mentioned, I was on smooth road). It normally happened during acceleration. I took it in the first time and the dealer replaced the whole front end. Problem solved. 10K miles later it came back. Had them look at it again. This that time they tried other things to narrow in on the issue. Just prior to me saying "screw it, replace the whole front end again" my lease was up so I didn't bother with it. I feel your pain, it's a bummer. The only thing that I know that worked was replacing the whole front end.

GroundChuck, do you know what else they tried? I have reported this at 3 dealers and each of them has never heard of the condition that i am describing. I think im going to print up your last post and take it with me so they can see others have reported this problem.

LMMJ
02-09-2006, 11:26 PM
GroundChuck, do you know what else they tried? I have reported this at 3 dealers and each of them has never heard of the condition that i am describing. I think im going to print up your last post and take it with me so they can see others have reported this problem.
The dealerships could just be being lazy. I took my TB in once for the tail light recall and had two service writters tell to me that the parts weren't available to them. Well, I went back the next day when I was hoping other service writters would be there and got it done in 15 minutes. They may just not want the work PERIOD. They may have had others before and know how big of a job it is and passed on it.:m2:

03PoloBravada
02-09-2006, 11:53 PM
maybe, its just really making me mad. And they have driven the vehicle with me in it many times and the stupid thing does not clunk once with the service manager in the car....go figure.

LMMJ
02-09-2006, 11:54 PM
maybe, its just really making me mad. And they have driven the vehicle with me in it many times and the stupid thing does not clunk once with the service manager in the car....go figure.
they tend to "behave"`when at the dealership.

GroundChuck
02-10-2006, 12:33 AM
03Bravda,
I am honestly not sure what they tried during the last fix attempt (I assume that's the one you are referring to). By that time it was towards the end of the lease and I was getting sick of the problem.

When they did the full replacement the first time they replaced : L & R Front axle shafts, power steering gear on Right Front strut assm, diff carrier, and re-aligned the front end (I pulled my old paper work to verify).

Hope this helps.

03PoloBravada
02-22-2006, 05:55 PM
Well the clunking was really bad on Monday and I was able to take it to the dealer and this time when I had a service tech drive it it clunked for him. They told me to drop it off Tuesday morning so they could hook it up to the tech tool and go from there. So they call me Tuesday evening and said they have to tear into it some more to find the problem so I said do whatever it takes to fix it. They changed the encoder motor and the vehicle still did it. They called me today that they are going to check the fuel injectors but the computer says its not missing or anything.

The comment that really got me thinking was the service manager said...."if this was my horse id take it out back and shoot it".

New to TB
02-22-2006, 06:26 PM
The comment that really got me thinking was the service manager said...."if this was my horse id take it out back and shoot it".
:rotfl: :rotfl:

Sorry brother, good luck with her.

03PoloBravada
02-22-2006, 09:10 PM
I just hope it gets fixed. The problem started over a year ago and has only got worse with time. The truck only has 22,000 miles. Dealer still has the vehicle so maybe they found something else.....i dont know.

GroundChuck
02-22-2006, 11:21 PM
Good luck getting it fixed. Hopefully they find something.

03PoloBravada
02-23-2006, 04:20 PM
Well the fuel system checked out ok and all pressures were good. Dealer is still keeping the vehicle because it is still clunking. :confused:

03PoloBravada
02-25-2006, 02:41 PM
Got the Bravada back on Friday....and still no idea what is wrong. The dealer has a tech computer hooked up the the diagnostic port right now and as I am driving I am to hit this record button whenever the Clunk happens. Once I get 3 records, it goes back to the dealer so they can look it over. They have it set to record engine data because they think it is missing, causing the clunk. I still think its something in the AWD, but they are also going to set the recorder next time for the transmission then the AWD system.

03PoloBravada
03-01-2006, 10:41 PM
Well talked to the dealer today about the computer recordings. The engine data showed that during the clunking the timing was being advanced up to 18 degrees. This was the only reading from the engine that stood out. Now they have the recorder back in the vehicle and it is set to record transmission and transfercase data.

Also had a strange thing happen when my mom shut it off. The dash lit back up and the radio lost time and the ignition was off with the key out. The radio has blinked out and lost the time in the past, so were going to report that to the dealer now also.

GroundChuck
03-02-2006, 12:51 AM
Wow, what a saga. You've got far more time into fixing the problem than I did. It sounds like they are making some progress though. :crazy:

03PoloBravada
03-02-2006, 08:57 AM
Wow, what a saga. You've got far more time into fixing the problem than I did. It sounds like they are making some progress though. :crazy:

Yeah it has been a lot of trips and calls to the dealer lately for me. Im just trying to get the problem fixed. I love the vehicle and it only has 23K and it still has a little more than 2 years of b2b warrenty from GM, I got the free 5 year from GM when they were offering it on OLDS, so it is worth trying to fix.

MTPockets
03-02-2006, 09:58 AM
How many miles are on your bravada? Have you looked at the level and 'condition' of the front and rear differential oil and transfer case oil? Does this clunking happen on smooth surfaces AND under load? Transmission torque converter shudder happens in rapid sucession like that & feels almost like driving over a big rumble strip. I'd start with the easy stuff like checking all the oil levels.

G/luck
Joel

03PoloBravada
03-02-2006, 01:20 PM
How many miles are on your bravada? Have you looked at the level and 'condition' of the front and rear differential oil and transfer case oil? Does this clunking happen on smooth surfaces AND under load? Transmission torque converter shudder happens in rapid sucession like that & feels almost like driving over a big rumble strip. I'd start with the easy stuff like checking all the oil levels.

G/luck
Joel

23,000 miles. Dealer has checked all fluids first and all are fine. The clunk, pounding, feeling is felt on smooth surfaces while accelerating or crusing between 20-40 mph.

MTPockets
03-02-2006, 02:31 PM
Can you get the truck to do it in all gears (L,2,3,D) by shifting manually? Does it do it in 2wd and AWD mode? I have seen limited slip rear diffs clunk/chatter/bang when they dont have the right oil additive in them. That's usually on low speed turns though. Keep working at pinpointing exactly which conditions cause it and where it's coming from.

G/luck
Joel

GroundChuck
03-02-2006, 09:21 PM
I agree it's worth fixing if you bought it. I loved the one we had too. I was actually wishing that Olds would have stuck around long enough to have a Bravada version of the three row vehicles I would have choose that over our 3 row TB. I still think I like the Bravada/Rainer/97X family, then the TBs, then the Envoy family (no flames from the Envoy guys, you're still cool :) ).


Yeah it has been a lot of trips and calls to the dealer lately for me. Im just trying to get the problem fixed. I love the vehicle and it only has 23K and it still has a little more than 2 years of b2b warrenty from GM, I got the free 5 year from GM when they were offering it on OLDS, so it is worth trying to fix.

03PoloBravada
03-15-2006, 05:45 PM
Vehicle has been at the dealer again for 2 days now and they are trrying to narrow the problem down. On 3 occasions I had a tech tool recoreder in the vehicle, once it recorded engine, then transmission and then AWD systems. The dealer reviewed that information and trided a few things that did not solve it. Most reciently they just changed all axle and transfercase fluids, and now they say that it is doing it even worse and more often then before the fluid change. So they called today and said they are keeping it another day. I hope they are on to something now.

NorthRainer
03-26-2006, 07:37 PM
The feeling is not from hitting potholes, it feels like hitting potholes in the vehicle while on smooth pavement.


My Silverado did exactly the same thing in the front end. If I turned the wheel just a slight bit you would feel a bumping sensation (and clunking) in the steering wheel it felt like the drivers side front tire was hitting minor bumps, when I actually wasnt. There was a tech bulletin out for the Silverado though stating that the condition was normal so I cant tell you how to get it fixed.

I have never felt the condition you are describing in my Rainer

03PoloBravada
03-27-2006, 09:13 PM
Well after the dealer changed all the fluids it was doing it alot, so they drove it for about 20 miles and then changed it all again. So far a week later and it has not done it once for me. Maybe its fixed. The dealer said the smart trak fluid should be changed every 30K, but I just rolled 23K and the condition I had has been there for awhile now. Hopefuly it is fixed for good.

Also, I dont know if it is because they flashed the computers so many times and played with the engine settings but wow it drives like a different vehicle now. It feels very responsive, and its just much smoother to drive. So far it is great so I am happy... I hope its fixed.

mjd932
03-28-2006, 02:04 PM
I hope it's fixed for good for you. The only thing I've noticed in my Rainier is that sometimes after driving a very short distance and stopping, before I take off again I will feel a little clunk like it's going into gear (which makes no sense). I don't know if that's normal or not.

sanger35
12-08-2006, 09:30 PM
I assume you have a transfer case with AWD. My Trailblazer was bucking in AWD, okay in 2WD, 4WHi and 4WLo. Had the transfer case fluid changed and its back to normal. Maybe the dealer didn't get it filled up enough the first time...

mstazlee
12-11-2006, 09:30 PM
I'm glad you got your bravada fixed. I have an 02 that had 60,000 miles on it before the AWD broke. I didn't have any light coming on in the dash about servicing the AWD. I noticed that when making turns it felt like I my wheels were locked in. I thought it was do to my tires being worn out and low in air pressure. I went to a transmission garage and they looked underneath and found my transfer case leaking. When they started taking it apart they found the transfer case cracked on top about 8" long. Well they couldn't rebuild it because the case was on back order from Rockwell. Where the garage gets his parts. So I found one at a salvage yard that had 61000 miles on it. The garage put it in and it was still locked in all wheel drive. He had a computer and plugged it in to my car but couldn't find any problems. So he suggested I get the transfer motor from the salvage yard. Well that lasted 4 days. I ended up bringing it to a gm garage and they were stunned on what was wrong. I told them that when they changed the motor it worked. So this time I got a new one and had them put it in. And it works fine. Come to find out the salvage yard sent me the wrong one. I needed one with option np4 and they sent me one without. I did get my money back but lost money in labor. When this transfer case went I didn't have any clunking sounds. I didn't see any oil leaking on the ground. I've learned that if I have a problem I am taking it right to a garage. I did drive this for a while with a small leak but it ended up costing me a lot of money. I have since put new tires on it and had all the fluids changed. I did get a clunking sound in the front end afterwards and the garage told me it was my bushings. Nothing to worry about now. But will have to change in the future. Last note with having an 02 Bravada the only transfer case that works is an 02.
Very hard to find. I found one transfer case in all of New England.
I am glad that I found this site because it has been very helpful. No question is a stupid question. Everyone is very nice at helping.:)