Differential Bearings info - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

DataXUnknown · 01-21-2009, 05:23 PM

I was just reading up a thread back in 2007 and I'm kinda relating to it. Basically, there are wierd noises coming from my Diff, it is Welded. The noises ONLY come for some reason in 5th gear.

To me, it sounds like somthing isn't balanced. It makes vibration when I step on the gas. I was reading about backlash and differential bearings and I couldn't find much information on exactly where and what they are.

So what exactly is "backlash" and how would you go about measuring it? Also the diff bearings, are they located outside the pumpkin where the axles would fit into? Oh and I can make the sound go away for the most part by shifting it out of 5th, and then putting it back in. Somtimes it takes a couple of tries. There is no grinding or anything though so I didn't think it would be the tranny.

thelinja · 01-21-2009, 05:32 PM

Backlash in the differential is the amount of "play" between the pinion gear and ring gear if you move them back and forth. It's usually measured with a dial gauge, but you have to take the diff apart to measure it. This doesn't really sound like a backlash issue to me. Did you install the diff?

The differential itself has four bearings (two of which are pressed onto the diff, the others are on the pinion gear). If one of those bearings fails, the noise should be constant and it shouldn't matter what gear you're in. At least that's what I've experienced. I had to replace a pinion bearing last spring and it didn't matter what gear I was in, it made constant noise. It may be your 5th gear going out.

DataXUnknown · 01-21-2009, 05:45 PM

I can understand where you're coming from. But the sound comes from the rear, maybe even the driveshaft area. My hatch is gutted so I can pinpoint pretty well where the sound is coming from. Thank you for the info on the bearings and backlash.

And yes I did install the diff myself. I traded my open diff for a welded awhile back. It had at least 2 years of driving on the diff before I got it, and now when I got it it's had another year, and it's also leaking a lot. If it's low on fluid could that matter? Since it was welded I just kinda didn't care about the fluid level.

01-21-2009, 05:23 PM	#1
DataXUnknown Post Whore! Join Date: Sep 2006 Location: Mission Viejo, CA Age: 35 Posts: 2,934 Trader Rating: (30) Rides Gallery: DataXUnknown Feedback Score: 30 reviews	Differential Bearings info I was just reading up a thread back in 2007 and I'm kinda relating to it. Basically, there are wierd noises coming from my Diff, it is Welded. The noises ONLY come for some reason in 5th gear. To me, it sounds like somthing isn't balanced. It makes vibration when I step on the gas. I was reading about backlash and differential bearings and I couldn't find much information on exactly where and what they are. So what exactly is "backlash" and how would you go about measuring it? Also the diff bearings, are they located outside the pumpkin where the axles would fit into? Oh and I can make the sound go away for the most part by shifting it out of 5th, and then putting it back in. Somtimes it takes a couple of tries. There is no grinding or anything though so I didn't think it would be the tranny.

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01-21-2009, 05:32 PM	#2
thelinja Zilvia FREAK! Join Date: Jul 2002 Location: New Jersey Posts: 1,466 Trader Rating: (3) Rides Gallery: thelinja Feedback Score: 3 reviews	Backlash in the differential is the amount of "play" between the pinion gear and ring gear if you move them back and forth. It's usually measured with a dial gauge, but you have to take the diff apart to measure it. This doesn't really sound like a backlash issue to me. Did you install the diff? The differential itself has four bearings (two of which are pressed onto the diff, the others are on the pinion gear). If one of those bearings fails, the noise should be constant and it shouldn't matter what gear you're in. At least that's what I've experienced. I had to replace a pinion bearing last spring and it didn't matter what gear I was in, it made constant noise. It may be your 5th gear going out.

01-21-2009, 05:45 PM	#3
DataXUnknown Post Whore! Join Date: Sep 2006 Location: Mission Viejo, CA Age: 35 Posts: 2,934 Trader Rating: (30) Rides Gallery: DataXUnknown Feedback Score: 30 reviews	I can understand where you're coming from. But the sound comes from the rear, maybe even the driveshaft area. My hatch is gutted so I can pinpoint pretty well where the sound is coming from. Thank you for the info on the bearings and backlash. And yes I did install the diff myself. I traded my open diff for a welded awhile back. It had at least 2 years of driving on the diff before I got it, and now when I got it it's had another year, and it's also leaking a lot. If it's low on fluid could that matter? Since it was welded I just kinda didn't care about the fluid level.