Anyone experiencing a Gearbox Whine might want to read this.
Hey there everyone,
I was curious to find out how many 996 street car owners have noticed a whine in their gearbox? Sometimes you might notice that this will change in pitch or volume depending on your throttle position. Well I thought that I would address what has caused this with everyone, so that you can appreciate how important it is to get this taken care of sooner rather than later.
This gearbox has essentially 4 bearings inside of it that control the forces generated by the pinion and main shaft. Two of these bearings are the culprit of the whine that you might be hearing. These two bearings are quite pricey at about $480.00 each, however have a very important function. They essentially maintain the distancing of the main shaft and pinion shaft.
There is one on the main and one on the pinion and they look like what is shown in picture number one. These are sealed bearings, which you might think would be a good think right? Well usually this is a good thing, however, there are instances where this can also be a bad thing. While they do a fair job of keeping particulates out of the bearing races, once debris does push itself in there, this design does an even better job of keeping it there. As this bearing continues to do its work the particulates that are trapped inside the bearing also begin to work. In a very negative way, unfortunately.
Picture #2 shows the inside of one of these bearings after some of the damage has been done. As you can see the inside of the bearing is fairly pitted up. This is what is generating the whining noise that you are hearing. It is important that this be addressed sooner rather than later, as this is also generating additional heat. Heat inside this bearing is a particularly bad thing.
Picture #3 shows how this bearing is actually constructed inside. You will notice that the cage that holds the ***** in place is constructed of plastic. While this is not a bad design in and of itself, it is a bit more sensitive to increased heat. Should the internals of these two bearings get too hot, the bearing will ultimately fail. This can generate a very large repair bill, as well as potentially lead to complete failure of the gearbox itself.
Now don't get me wrong here, I am not trying to stir anything up or be overly sensational about this issue. I simply thought that you might actually like to see what was going on inside and make the recommendation that if you should notice this problem, it would be in your best interest to get it taken care of in a timely fashion, rather than wait for complete failure to occur.
I hope that this has been at least a little educational, please don't hesitate to contact me with any questions that you might have. I am always here to help. We have been building these gearboxes for quite some time, and while they are somewhat tricky they can usually be turned around in less than a week.
GBox Performance Transaxle
(303) 440-8899 work
(303) 895-4828 cell www.gboxweb.com
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Why didn't you post this a year and a half ago before I dropped a Sh*tload on a new tranny after being told that these bearings seized on the shaft. Oh well. Hopefully this will help someone else.
Any smart ideas about the front c4 differential? Being told by the stealership that the front diff is going to have problems ( I believe them, slight whine. So I keep the top down and the radio up) but that I have to replace the whole axle!!! The service guy gave me a wink and said he couldn't answer me when I asked if I can just replace the guts instead of buying the whole thing but he said he can only order the entire axle not just the inside parts. Would appricaiate any help.
Ahhh the 996 with its infamous bearing problems...LOL
Notice all of these "infamous bearings" are sealed?? Must have been a good idea on some engineer's CAD screen and on some procurement manager's BOM, but boy do they seem to be a pain to all of us "users".
I think the key is to be in tune with your car, and address these items when they become apparent (like the whine Eric describes).