Driving the past couple of days I noticed a distinct vibration. It is not jarring but is definetely enough to annoy. The most noticalbe time is when I first dirve the truck each day. Usually a couple miles to the highway and after a mile or so about 60-65 MPH the converter locks and I feel/hear a vibration immediately. It disipates when the load is removed but is present cruising and accelerating.


I tried it in T/H and noticed in most of the gears. I checked my fluid it was maybe a pint low but when filled it didn't make any diff. I question the level, after 20 Mi. on the highway tranny temp about 140-145. If does seem to lessen when warmed up but is still present. I am off to the dealer Monday to have my PS windshield leak fixed http://www.dieselplace.com/forum/smileys/Angry.gif and will have them look at it.


I had noticed a vibration previously when in T/H only and only between 2000-2200 RPM (early fall) and around Christmas when in 4WD at 55+MPH and am now wondering if they may all be related. Any input/experience would be appreciated. Thanks in advance for any replies.


MikeEdited by: HisDMAX

Mine comes on very very slightly in T/H between 50 and 55, 4wd right at 60. I have an appointment next Saturday. Mine is an 01, but the problem sounds about the same. I'll let you know what they find if yours isn't taken care of on Monday. Would appreciate it if you'd let me know what they have to say on monday.


Thanks,

The 01's had problems with lose bolts ... Mine had one that was finger tight ...


With the 03 has revised TC bolts .... Good luck Mike let us know what happens ....





Mac

Thanks for the info on the 01. I'll be checking the bolts this afternoon.

I took it to the dealer to listen to the trans. and at least they fixed the windshield leak. Of course I don't really know because the last thing we are going to see is rain at 5-10 degrees!! http://www.dieselplace.com/forum/smileys/Shocked.gif


Anyway, the tech drove my truck and didn't hear anything. Service writer wanted to drive and listen himself and takes the diesel tech with him. "nothing out of the ordinary" heard. The writer did check for TSB and GM and there are no others experiencing what I am and he said it is documented if it becomes a prob. I guess because 150 others don't have the same issue and there is no TSB then it isn't a problem????


I questioned if it was just me but it isn't!! I put the truck in T/H and I hear this noise just when the TC locks at about 1800 RPM it does seem to disipate when the RPMs are higher 2300RPM. The only time I notice it when not in T/H is once the TC locks until 70+ MPH (the majority of my highway driving). In the truck it almost sounds exhaust related but it correlates way to much with the TC.


I drove around in T/H letting it shift from 1st to 2nd to 3rd. Going from 2nd to 3rd is when notice a slight fluctuation in RPM and hear it start. It is bugging the heck out of me. http://www.dieselplace.com/forum/smileys/Angry.gif It seems to respond to load when in 4wd the other day it was quite noticable. I will fill my dump trailer with rocks or something this weekend and I am almost sure it will be louder.


Rant over! What is the chance that I can get a tech/service writer to accompany me some time? A snowballs chance in...... bad analogy.... but you know what I mean!!! Any thoughts?


Mike

I have the same problem with my 03. Vibration comes on about 50 mph and goes away at about 70 mph. Is much worse in 4wd and like you said it goes away when I let off the throttle. So far I have balanced and rotated the tires with no effect. The dealer has had the truck on two seperate visits and has checked tires, driveshafts and torque converter bolts. They can't figure it out. On monday they are going to try swapping parts out with a new truck. I will post thier findings. My suspicions are that it is the front diff or driveshaft. Would you describe your vibration as like driving over small rumble strips?

My 02 does the same thing. It started in the Spring last year, and vibration comes on from 55-65.

Ditto my 01 complete w/ suncoast TC.


I don't think the TC causes the vibration, I think it is related to the front diff, only because is gets louder when in 4 wheel drive. The TC locking may transmit more of the vibration though the body of the truck but I think it is coming from someplace else.


My only thought is tire pressure, the front of the truck weighs almost twice as much as the back, yet I think my tire pressure is the same all the way around. Front tire diameter is probably significantly smaller.


Would this cause gears in the transfer case to bind slightly?


Just a guess.

I think the theory of the transfer case binding slightly could hold true in 4wd. In 2wd however the front and rear wheels should be isolated from one another.


I think it is something to do with the front diff. as well. The fact that it is worse in 4wd points to the front end. Along with the diff, front axles theory maybe it could be a front wheel bearing problem.

MIne has the same vibration... but only with the juice installed... I took out my juice, and after a few days the vibration was gone.... Put back in the juice, and after 100 miles, it was back..... Are any of you guys adding power?http://www.dieselplace.com/forum/uploads/6ZB_burnout.gif

I am going to just run mine with a load this weekend and see what happens.


403 - The dealer was instructed to check the turbo bracket to see if it was cracked after "calling Detriot" (Oh man it sounded so official!!! Bear in mind his quoted comment was in the same breath when he "reminded me" of the satisfaction survey and it's importance LOL). Anyway, it is worth checking. As I have said it does have a sound like it could be exhaust related but on a cold morning like today at 0 degrees, hit the highway and when the TC locks there it is!


I'll monitor it. If it keeps up maybe a 4" Banks system might help neutalize ithttp://www.dieselplace.com/forum/smileys/Approve.gif.





Mike

With the front dif, in 2wd, the front shaft is stationary and the outer axle shafts only spin the spider gears inside the carrier assy.

I don't see where that would do anything noticable unless you have something wrong with a wheel bearing or CV joint.

Yes, it sounds a bit like going over rumble strips. Not quite as bad though. I do not have any of the power chips, completely stock. I'll be at the dealer at 0800 tomorrow. I'll let you know what this one says. I already have it arranged to have the tech take a ride with me so I know he'll get to hear/feel it.

Ok, took mine in this morning. I took the tech for a test drive to make sure he knew what noise/vibration I was talking about. As soon as I hit 60 in 4H it started. he said he was pretty sure what it was, and he was correct, as the shop had taken care of sevrral with teh same symptoms. The front diff pinion torque was almost double what it should be. The bearing is now bad and has to be replaced and the T/C front output shaft bearing is starting to go. This is not a problem unique to mine, he has seen it on several others. I'd say have your tech drop the front driveshaft, and check the pinion torque and bearing. Good luck.

Oldman did you have this noise even when not in 4WD?


Being the front diff pinon it should only be turning when in 4WD. Mine is more noticable when in 4Hi but also when its not, and it does seem to be worse when TC locked.


Just trying to convince myself that we have the same problem before I tell the tech to rip off the front axle @ $68 an hour.

I have heard the noise in 2WD. You're right, it should not be there if it's coming from the front diff. I never really paid much attention to it, it may have been just after coming out of 4WD. I have to wait a week for parts to get up here - can't believe they've had this problem with other trucks and don't have the bearings and seals in stock!! Anyway, I'm not headed out again today but I will check tomorrow and let you know what I find.

The dealer had another look at my truck today. (4th trip) They are still not sure what is causing the vibration but have heard of the problem. They are still waiting to hear from GM on a possible cause. I mentioned what your dealer found Oldman about the front pinion bearing. They are willing to try changing the bearing on Tuesday. I will keep you posted if this turns out to be the cause. It looks like it is a difficult problem to troubleshoot as there are so many possible sources of vibration.

The dealer is done troubleshooting. They went through a process of elimination until nothing was left but the engine and the tranny. With the truck on the hoist and no driveshaft hooked up they had a vibration at 1900 rpm. This was in more than one gear but not sure which ones they checked. It sounds like at this point they disconnected the tranny and the engine ran vibration free. When I take it in next they are going to check for obvious causes in the tranny. It was indicated though that they don't actually fix the Allison's, they are replaced. I'll let you know how that goes.

The early Ally has had failures at the stator support bushing(where the input shaft come out the front of the trans). This in turn will prematurely wear out the pilot bushing on the input shaft where it mates to the intermediate shaft. This can cause a converter shudder. I have not felt this in a truck yet and have not had anyone complain about it yet. The new stator bushings are teflon coated. The are the only ones i have seen on my customers trucks. I now have an Ally core donated by TTS and it's an early '01 and it has the early bushing and it's totaly worn out. This unit must have had a converter shudder.

The vibration was there in 2WD but not much at all. An inspector is comiong by the dealership today to see if they will rebuild or replace the T-case!

Mike L. what year did they change the bushings? Any idea? I have an 03 and this seems most like what I am experiencing. It is def. TC/tranny related right now they say "it sounds normal" The funny thing to me is if this is normal then my truck was not normal before! I am going to drive and wait. If it is a problem it isn't likely to "heal" and I will be using 4wd as much as possible as it seems worse then. Where is that satisfaction survey anyway?


Mike

HisDMAX


The bushing was changed in '02, maybe late '01. I have felt these type of vibrations on many, many different cars and trucks. It usually will act up after 2-3 shift then the lock up clutch will come on with a shudder.( like a washboard road). I have never felt this in the Ally. i have driven some wasted Allys, but have not felt this. (doesn't mean it doesn't happen). My usuall test for this is;(you must drive with both feet) get the truck up to where the vibration occurs and try to hold a steady speed and keep the vibration constant, then lightly tap brake pedal with left foot, (brake switch releases converter clutch electronicaly) watch the tach to see if rpm's went up a bit(that tells you that you did release the clutch). Now, did vibe go away? if it did , then it's converter related. if it did not go away, then look elsewhere.


mike

Mike L.


Thanks, I'll try that and see what happens.


Mike

I have what sounds to be exactly the same problem. I've had it for over a year now. Just used 4wd yesterday in the snow and man when it dropped into 5th under load, WoW!!! Like you said it is there in 2wd but very pronounced in 4wd especially w/ the TC locked. I took it to the dealer about 10 months ago and again like you they said there is no problem. They copyed the manual that said do not use 4wd in dry conditions ( i use it for racing), and also T/H does not need be used unless towing. What a crock!!http://www.dieselplace.com/forum/smileys/Disapprove.gif But atleast I have it on record, not that that matters. I hope someone figures it out because it bothers me alot, but i have learned to live with it.


I am really suprised that even a Suncoast trans has this problem, that is scarey. I thought for sure a suncoast trans/converter would solve the problem, unless that is only half of it and the other half is the fron pinion bearing?? Who knows, but I'll keep and ear open hear because I would love to know the cause of this 40k vibrator.


Jason

I tend to think that if you have the same vibration with a Suncoast, it's not the trans.

Well I have the Transgo kit with the Suncoast convertor, so could it be bearings in the trans itself, yes I suppose it could. It was rebuilt by a very skilled tranny builder and I feel that if wear was seen it would have been addressed.


Being out of warranty and given that even in 4hi this is not a consistent issue I am not going to knock down the dealers door trying to get it fixed.


My truck has a little added character now and thats all it is. If it grenades I'm sure I will feel differently.


At 70,000 miles operating everyday at 150% of rated power I'm not gonna freak over a vibration at 60 mpg in 4 wheel drive.


http://www.dieselplace.com/forum/smileys/Evil Smile.gifIn warrantly and stock I would be in the dealers face.http://www.dieselplace.com/forum/smileys/Evil Smile.gif

403turbo


I don't think your vibration is in in the trans. The Ally has needle thrust bearings inside; but if they were bad you would be in limp so fast it would make your head spin.(metal and solenoids are not friends). The Ally also has an output shaft roller bearing (i have not seen a bad one yet) but, i would think it would make noise along with the vibration. Every other trans with output bearing i have worked on has made noise when bad. Usually noise comes before vibration. Vibrations are tuff, guys, i fight them on a regular basis and it is easy to get fooled. We tend to throw money at them in my business. I think Eric might be able to throw some light on this.

Mike L.


Thanks for your input. I tried the 2 footed approach to disengage the TC and it didn't make a difference. If it is not the TC what else might be effected by the TC locking? I am thinking maybe the Trans case? Mine is there in 2wd but much more so in 4wd. On a cold morning the first time the TC locks on the highway is most noticable. Arghh!!???


Mike

I managed to sneak a peek at the work order on my truck. No way in hell an over tightened nut caused all my problems. Lots of metal in the front diff and the t-case. All bearings and seals are being replaced as well as the pump in the T-case!!

I HAVE AN 02' WITH THE SAME SOUND. HAVE HAD IT IN TO THE DEALER MANY TIMES FOR SERVICE 4 WHEEL DRIVE LIGHT, AND THE HOULING. FIRST TIME IN, TOOK SERVICE TECH W/ ME, HOUL WAS BAD IN 4X4 @ 60 MPH, WORSE IN TOW HAUL MODE. THERE SOLUTION BRAND NEW FRONT DIFFERENTIAL.(COST TO CHEVY-$3000.00). THAT DIDN'T DO IT, SECOND TIME IN STILL GETTING SERV. 4 WHEEL DRIVE LIGHT, AND BAD HOUL. THEY TIGHTENED T/C BOLTS, SAID ONE WAS LOOSE, AND LOOSE CONNECTION ON ENCODER MOTOR WILL SOLVE MY LIGHT PROBLEM.


WELL NEEDLESS TO SAY 2 WEEKS LATER, SERV. 4X4 LIGHT ON, HOUL IN 4X4, LOADED W/ 4 GUY'S, 4 SLED'S, IN AN ALUMINUM ENCLOSED TRAILER IN TOW HAUL MODE AND 4X4 YOU CAN FEEL IT THROUGH THE SEATS IN TO YOUR STOMACH SO BAD IT MAKES YOU SICK @40 MPH!! OH,AND DID I ADD 9.1 MPG ON THAT TRIP GOING 60 MPH!!http://www.dieselplace.com/forum/smileys/Angry.gif


SORRY TO VENT SO LONG, BUT LETTERS ARE BEING TYPED AND PHONE CALLS ARE BEING MADE, CHEVY HAS TO KNOW THEY HAVE A PROBLEM, AND THEY NEED TO STAND UP TO THERE PRODUCT. WHEN WE PAY AS MUCH AS SOME PEOPLES SALARY'S FOR OUR TRUCK'S THEY DAMN SURE BETTER PERFORM LIKE A $40,000 TRUCK SHOULD!!

WHEN WE PAY AS MUCH AS SOME PEOPLES SALARY'S FOR OUR TRUCK'S THEY DAMN SURE BETTER PERFORM LIKE A $40,000 TRUCK SHOULD!!


AMEN!! I was kind of surprised I didn't get a new T-case out of this. believe me, at the first sign of the problem showing up again it will be back to the dealer!!

The dealer has told me today that they will be replacing my transmission. They tore it apart on thursday. They found some scoring on the main shaft and bushing. They feel there is an alignment issue with the main shaft. Hopefully I will get a replacement next week. I still have a bit of doubt about this being the problem, but I'll know for sure next week when I take it for a drive. They said they found no loose metal, I am wondering where this scoring could have come from?

Hey, let me throw my 2 cents in here. I have what I think is the same problem here. On the highway if I'm on the gas (accelerating or holding a steady speed) I get this "rumble noise". if I let up on the gas, the noise goes away. It sounds like the noise is coming from the front of my truck somewhere.


Here is one catch different from you guys:I have a 6.0 gasser with the 4l80E (2001, 2500HD). Seems most of you have D/A combo's. So my problem may or maynot be the same as yours. Some guy over at RV.net has the same sounding problem with a 2004, 2500HD 6.0 gasser. In fact he said the few they tried right off the lot had this noise.


I'm somewhat convinced in my case its engine noise. One way to prove this is when I pull on the highway cold (just starting out) the noise will go up with the revs of the engine. The truck will turn over 2500 rpm in 4th on the highway before the TC locks up. Once the tranny locks up the RPM's drop about 300-400, and the noise level decreases even though I'm going the same speed, or faster. As I speed up back to 2500-3000 RPMs the noise keeps increasing with the RPM's


Not sure what I'm going to do about it... is way too cold out to crawl under the truck.


ON Edit: BTW I noticed both here and other boards people complaining that in 4wd their trucks make noise at 50+ MPH. My 1990 chevy K-1500 made a noticable rumbling noise in 4wd at higher speeds. My new 2001 2500HD also makes the same exact runble in 4wd. I can't speak for other brands as I've only owned chevy's ut I heard from more than one person this is "normal". The front end "stuff" was/isn't balanced/designed for high speed driving. The other comment is why would you be doing 50+ MPH in 4wd anyway?Edited by: jimmarako

They finished up with my truck yesterday. New tranny, still have vibration! They have either missed something in the troubleshooting or perhaps there is a grounding problem. I am going to just carry on for a few thousand more kms and see if it gets worse.


I am still of the opinion that it is a driveshaft or front cv joint problem. A friend of mine has the same problem on his truck. Another thing we have both noticed is the noise changes when going over whoops in the road sorta like a roller coaster. This could be due to the angle changes in the front axles, or if something was rubbing it could come and go.


If the gasser trucks are getting the same vibration that would eliminate the tranny and most of the drivetrain as being the issue as they are different in the d/a trucks. Not sure about the transfer case forward though.


Driving in 4wd at highway speeds is not an issue. I have been doing it in my 99 every winter. No rumble, no vibration. As long as there is ice or packed snow on the pavement it is acceptable. I would never do it if I could see pavement though. I believe some front diffs and transfer cases are noisier than others and this could account for the differences. Edited by: charlielake

Hey guys, How many of you have two piece drivelines?? I lifted my 01 d/a truck with a 4" block spacer in the rear and developed the same problem you guys are talking about. It wasn't noticable before i lifted it. Has the wobble from take off in addition to the vibrations mentioned. If the new tranny...t/c etc does not fix it maybe look at the driveshaft. I think it is tsb 01-04-17-001a


I will be listening to what you guys find.Edited by: Gray Gmax

WELL, HERE IS WHAT I GOT. I HAVE JUST TURNED ABOUT 1500 MILES ON THE NEW FRONT DIFF. IN MY O2' LISTED EARLIER. I'M ABOUT TO CHANGE TO SYN. IN FRONT THIS WEEKEND. MY VIBRATION IN 4X4 HAS SLOWLY DISAPPEARED, NOW THE ONLY TIME I HEAR IT IS PULLING THE ENCLOSED TRAILER IN 4X4-HI, T/H AT ABOUT 2100-2200 RPM'S. ONCE IT SHIFTS OUT IT GOES AWAY. CAN SOMEONE TELL ME EXACTLY WHAT T/H DOES? AS FAR AS, DIFF. SHIFT CURVES, IS IT MOSTLY JUST COMPUTERIZED BS, AND HOW MUCH MORE ENGINE NOISE SHOULD WE NOTICE. ANY HELP WOULD BE GREATFULL!!

The other comment is why would you be doing 50+ MPH in 4wd anyway?





I live 40 miles from work, 25 of that is on a Hwy. Sure it's winter and yes there's ice and snow on the road but I drive 70 anyway. i need 4WD.


BTW, About the only thing that was not changed on my front diff was the housing. T-case got all new bearings, seals and a pump. Purrs along quite nicely now in 4WD at speeds up to 90.

Purrs along quite nicely now in 4WD at speeds up to 90.


http://www.dieselplace.com/forum/smileys/Shocked.gifhttp://www.dieselplace.com/forum/smileys/Shocked.gifhttp://www.dieselplace.com/forum/smileys/Shocked.gif


Man, what does that do to fuel mileage?