Rear end howl on decel

[OldScoolCamaro]

Originally Posted by Sven59

Two different issues, noise on deceleration in straight line is backlash off, replace ring and pinion. Noise two, usually when cold howling on turns. There is a tsb specific to ZL1, calls for changing fluid a couple times along with specific driving techniques. The cause is leftover lashing compound.

...you are correct on the noise and part issue that causes it. The tan lashing compound was really, really built up on the drain plug when I changed out my fluid at about 1,500 K. It was about 6/32 of an inch thick with the darker residual grease with contaminents and fillings/particles on top of that.

[ZMEnow]

Originally Posted by Sven59

Two different issues, noise on deceleration in straight line is backlash off, replace ring and pinion. Noise two, usually when cold howling on turns. There is a tsb specific to ZL1, calls for changing fluid a couple times along with specific driving techniques. The cause is leftover lashing compound.

Sven59 I seemed to remember that you had your rear end replaced, maybe not, but I noticed you comment on this issue alot. Therefore I am going to run something by you. My backlash was perfect, not a sound on decel or accel. Before I stored for the winter I had the oil changed and the rear end drained and new fluid. Yes I verified they used the correct fluid for the ZL1 as I think you provided that info in an earlier thread.

I had 3700 miles when the oil was changed, and the only thing I did was a 3500 rpm hole shot up to 3rd gear just make sure everything was good. When driving home I noticed the howling at around 68 - 70 mph, very narrow range with decel only. You stated that replacing the ring and pinion is recommended, but I am curious why I would do that vs. attempting to reset the backlash as is it was fine before this.

I am terrified of the problems I have read on here of people getting new rear ends, or shimming , and the problem only getting worse. When I read through the workshop manual it goes in to great detail on pattern wear for decel issues, but starts with a loose pinion as a first step check point. I have confidence in the GM tech that would do the work, but I know enough about rears ends that if you don't do it alot, you will probably will make things worse. Appreciate your response..

[The Stig]

Originally Posted by Sven59

Two different issues, noise on deceleration in straight line is backlash off, replace ring and pinion. Noise two, usually when cold howling on turns. There is a tsb specific to ZL1, calls for changing fluid a couple times along with specific driving techniques. The cause is leftover lashing compound.

It's howling when I let off the throttle if/when I'm going about 65 mph ish.

[OldScoolCamaro]

...then there is an issue with the materials involved. Whats wrong with the cake? Manufacturer defect with some of the parts...obviously not the setup if you describe an issue at that point through use. Or is it subjective interpretation. Something now, nothing before.... odd observation, does not compute.

[Sven59]

Originally Posted by ZMEnow

Sven59 I seemed to remember that you had your rear end replaced, maybe not, but I noticed you comment on this issue alot. Therefore I am going to run something by you. My backlash was perfect, not a sound on decel or accel. Before I stored for the winter I had the oil changed and the rear end drained and new fluid. Yes I verified they used the correct fluid for the ZL1 as I think you provided that info in an earlier thread.

I had 3700 miles when the oil was changed, and the only thing I did was a 3500 rpm hole shot up to 3rd gear just make sure everything was good. When driving home I noticed the howling at around 68 - 70 mph, very narrow range with decel only. You stated that replacing the ring and pinion is recommended, but I am curious why I would do that vs. attempting to reset the backlash as is it was fine before this.

I am terrified of the problems I have read on here of people getting new rear ends, or shimming , and the problem only getting worse. When I read through the workshop manual it goes in to great detail on pattern wear for decel issues, but starts with a loose pinion as a first step check point. I have confidence in the GM tech that would do the work, but I know enough about rears ends that if you don't do it alot, you will probably will make things worse. Appreciate your response..

The decel sound was the first problem I had, took it to the dealer and they found the backlash to be off, they replaced the ring and pinion. I have read many threads on here where people have had the same issue and resolved in somewhat the same manner. As for your issue, on the face it sounds like backlash and I am no expert almost everyone with the howling issue is in slow turns usually cold weather. That was the second problem and resolved with the TSB. I also have a great dealer who takes very good care of me, and he is always open to my input on things I learn here. If you trust the tech, go talk to him about the situation and things learned here. I am not sure about the harm to the rearend but if it is backlash that could be serious, I think the other one is maybe more of a nuisance I am not sure how over time excess lashing compound will affect it. I hope that helps, also search for more threads here, there are many.

[AquaSSRS]

Same here, mine makes the howl on decel at speeds over 45. I planned on taking it in to the dealer in the spring. My good friend is a service tech/mechanic (whatever the term is now) at my dealership, so I will take him for a ride once the road salt and cinders are gone. I probably noticed it around the 1400 mile mark and am currently at 2200 miles and it has gotten progressively louder.

[ZMEnow]

Originally Posted by Sven59

The decel sound was the first problem I had, took it to the dealer and they found the backlash to be off, they replaced the ring and pinion. I have read many threads on here where people have had the same issue and resolved in somewhat the same manner. As for your issue, on the face it sounds like backlash and I am no expert almost everyone with the howling issue is in slow turns usually cold weather. That was the second problem and resolved with the TSB. I also have a great dealer who takes very good care of me, and he is always open to my input on things I learn here. If you trust the tech, go talk to him about the situation and things learned here. I am not sure about the harm to the rearend but if it is backlash that could be serious, I think the other one is maybe more of a nuisance I am not sure how over time excess lashing compound will affect it. I hope that helps, also search for more threads here, there are many.

Thanks, when things thaw out in a few months I will go sit down with my tech and discuss. It just seems many here start out with problem and my didn't happen until 3700 miles with oil change. I was leaning towards the hole shot loosened the pinion nut, but this car better withstand a lot more than 3500 controlled slip start. When I was in college I did a summer at Fords gear and axle and was a gear lapped. I know you don't want backlash to go unattended, it just gets worse.

[Sven59]

Originally Posted by ZMEnow

Thanks, when things thaw out in a few months I will go sit down with my tech and discuss. It just seems many here start out with problem and my didn't happen until 3700 miles with oil change. I was leaning towards the hole shot loosened the pinion nut, but this car better withstand a lot more than 3500 controlled slip start. When I was in college I did a summer at Fords gear and axle and was a gear lapped. I know you don't want backlash to go unattended, it just gets worse.

Supposedly they did something like 8 or 9 hundred red line starts on the rearend, it is bombproof as long as everything is correct inside. I haven't heard of any blowing that I know of from the guys dragging them regularly.

[oldchevyguy]

This will be my final post in the ZL1 forum. After 4 months of waiting for a decision it happened last week. I was given the opportunity to have another differential installed and live with the end result, meaning if it still makes noise consider it normal for the ZL1. Or trade for a different vehicle and get monetary assistance from GM. As much as I loved my ZL1 in the beginning, it was not a difficult choice to make. I love the Recaros in my new SS! Happy motoring guys!

[JackalopeZL1]

Geesh that stinks.. I think I would have had set it up myself or had it done before I traded it off for a ss.. But In the end glad your happy!!

[oldchevyguy]

Thanks. It was such an awesome car but after 4 months of trying to get GM to just decide to do something I got burned out on it. This is my second Gen 5 SS so at least I know what to expect from it.

[OldScoolCamaro]

...I tried to have faith with the product... and it's within expectations for me, but there is some issue that I can't understand with the rear axle. They are given the same parts, it's put together under the same specs using tools where you can't miss on the line...what' the issue.

[oldchevyguy]

Wondered about that as well. When they put the new ring and pinion in the original diff they couldn't get it set up right using the biggest shims available for that diff. Then the new diff made noise constantly where the original on made noise only when decelerating. Mystery! After 4 months of trying to get it resolved I got tired and took the other offer.

[Destructo09]

Originally Posted by djnice

Mine has a whine on decel when in the 60 to 70 mph range. It happens when slightly letting up from nuetral throttle. I am not sure what can be done about it.

Mine is the same, if ii'm holding the throttle in a neutral position it whines a bit.

If there is something wrong you'll know it, a bad setup or bad gear set will make quite a bit of noise, mine goes away with my foot completely off and accelerating at all.

Completely acceptable in my book long as it doesn't do it on complete decel or accel.