This 1972 Chevy Nova with LS power has a really bad noise coming from its 12 bolt rear end. In this episode I take you through the process of diagnosing and repairing this noise. I also cover backlash, pinion bearing preload, bearing installation, setting pinion depth, reading gear tooth patterns, installing new gears, and other tips and tricks to make sure that the differential in your vehicle stays quiet and strong.
I hope you find this information useful!
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Links
Sorry I don’t have direct links to the parts used in the video as they were brought to me along with the car. These are the places where I get most of my differential parts and accessories.
Summit Racing: https://www.summitracing.com
Randy’s Worldwide: https://www.randysworldwide.com
Info on Identifying 12 Bolt Differentials: https://www.onedirt.com/tech/drivetrain/12-bolt-rearend-guide/
Diagnosing Ring and Pinion Issues: https://www.onallcylinders.com/2014/03/21/gear-doctor-quick-guide-diagnosing-common-ring-pinion-issues/
Tools
Pinion Depth Measuring Tool: https://www.raceplumbing.net/TD-Machine-11001-Pinion-Depth-Gauge-Deluxe-Dial-Indicator-Fixtures-GM-Dana-Ford-Mopar-Kit_p_84187.html
Dial Indicator Set (Checking Backlash): https://www.jbtoolsales.com/central-tools-3d102-dial-indicator-set-with-on-off-magnetic-base#oid=1002_1
Bleepin Jeep Pinion Tool: https://store.bleepinjeep.com/product/yoke-wrench-tool/
Astro Pneumatic Bushing/Seal Driver Kit: https://www.jbtoolsales.com/astro-pneumatic-7824-bearing-race-and-seal-driver-set#oid=1002_1
Shim Installation Tool: https://www.summitracing.com/parts/yga-56077?seid=srese1&cm_mmc=pla-google-_-shopping-_-srese1-_-yukon-gear-axle&gclid=CJ6Dj-DSxc0CFQgaaQodKbgFjA
Milwaukee Angle Die Grinder: https://milwaukeetool.com/Products/Power-Tools/Metalworking/Grinders/2485-22
Inch Pound Torque Wrench: https://www.jbtoolsales.com/precision-instruments-d2f150hm-torque-wrench-dial-with-memory-needle-3-8-dr-150-in-lb#oid=1002_1
CRC Brake Cleaner (5 Gallon): https://www.amazon.com/gp/product/B000M8PYRY/ref=ppx_yo_dt_b_search_asin_title
Brake Cleaner Sprayer: https://www.jbtoolsales.com/titan-tools-tekz-19419-spot-spray-non-aerosol-sprayer#oid=1002_1
CRC Rags: Sorry, I believe these are discontinued
Related Videos
What’s That Noise in My Differential?: https://youtu.be/lv94-bItw-I
How To Use a Pinion Depth Measuring Tool: https://youtu.be/S61Ut8tOu1o
ETCGDadsTruck Axle/Differential Rebuild (Part 1): https://youtu.be/F439MFi6qIk
ETCGDadsTruck Axle/Differential Rebuild (Part 2): https://youtu.be/vkSvYCqrlOI
How To Clean, Prep, and Paint a Differential FairmontProject: https://www.youtube.com/watch?v=il8nDlCepyc
Ford 8.8″ Differential Complete Tear Down FairmontProject: https://www.youtube.com/watch?v=Plvg0NTLraA
Ford 8.8 Assembly & Set Up (Part 1) FairmontProject: https://www.youtube.com/watch?v=5fARhE7v5Bg
Ford 8.8 Assembly & Set Up (Part 2) FairmontProject: https://www.youtube.com/watch?v=npUBF9Wj1Iw
Ford 8.8 Final Assembly FairmontProject: https://www.youtube.com/watch?v=P3Pb_eNLkQc
ETCGDadsTruck Playlist: https://www.youtube.com/watch?v=kCepnacqRuI&list=PLSzhQ6St-ov1g_GML2aVq6EN-_ShJ9G2o
The FairmontProject Playlist: https://www.youtube.com/watch?v=L22GsHQi7tU&list=PLSzhQ6St-ov2nxWVKCeU14Vt7JJ_QSZvs
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Stay Dirty
ETCG
Due to factors beyond the control of EricTheCarGuy, it cannot guarantee against unauthorized modifications of this information, or improper use of this information.  EricTheCarGuy assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. EricTheCarGuy recommends safe practices when working with power tools, automotive lifts, lifting tools, jack stands, electrical equipment, blunt instruments, chemicals, lubricants, or any other tools or equipment seen or implied in this video.  Due to factors beyond the control of EricTheCarGuy, no information contained in this video shall create any express or implied warranty or guarantee of any particular result. Any injury, damage or loss that may result from improper use of these tools, equipment, or the information contained in this video is the sole responsibility of the user and not EricTheCarGuy®.
That thing is awesome!! I'd love to take it for a walk on the beach 🙂
Glad you mentioned the break in on the gears. That’s key as you know to gear longevity. Your really a fantastically thorough mechanic. Folks are blessed to have you doing the fixes.
The classic “Craigslist rebuilt rear end†tear down.
I’ve got a slight vibration in my rear at 70-75 mph. 7.5 gm with a 3.73 posi. Feels like a ujoint or a driveshaft balance issue. Really sux on the highway. Any information as to how to narrow down the cause? Great video ETCG!
So I can pull the old bearing off and use as a setup bearing as long as it is the same brand
TIMKEN bearings are made about 15 minutes from me. I actually thought about applying to work there at one point
Really nice video! I really hope if you were in UAE, that you can fix my RRS 2013 Supercharged V8. My RRS has a whining noise similar to this video, but I am not sure where it comes from, either from the rear differential or from the propeller shaft
I recently acquired an experience-based Faux Expert Leisure rating on differential service for our ‘71 Caprice (hubby drive it in HS, but I’m doing most of the rebuild 🤓
Part 2: This video completely legitimizes all of my home repair shop tool purchases, including the 20 ton press that I just couldn’t resist when it was on sale. Just saying…
hey I did that exact model car!
Excellent video but you were unclear on whether you liked the 4.11s or not. Ha ha!!! What transmission is in the Nova? Thanks. Cheers mate!!
Thoroughly enjoying your vids. Great attention to detail.
can you tell me what hydraulic press that is. thank you.
Absolutely loved this video. Always great content. Thank you Sir!
great video excellently detailed…makes me not want to rebuild my 12 bolt.
At the beginning of the video – but wondering why a new diff cover when it already has a good one…
I ordered the BleepinJeep pinion yoke tool about five minutes before watching this so that's good new. Good video. I still dread this job though.
What cleaning fluid to you use? I'm a DYIer and been using brake cleaner, but I go through way too many cans of the stuff; it gets expensive. Thanks for the video. Love the channel.
my first car even the same color WYYYY do we sell them? man i miss it
With different gears is your speedometer reading wrong?
Good video. Great camera work!
I said camaro last muscle great car I went Pontiac fiery bird, transAm. 2016' yeah end of game the satanist had a concept fiery trans Am they wanted to bring back out but they r playing 1 script serving satan & we r on a new script concept blown.
Be a gear head!!! Yessir!
bag of marbles, like all our old cars no?
That lamp is about to fall
Can you check the backlash from the yoke? Would like to check mine before complete tear down.
GM made three “types†of 12-bolt carriers (Type 2, Type 3, and Type 4). Thats the issue you ran into with the pinion difference. Here is a good page on a GTO forum that explains how to tell the 2,3,and 4 carriers apart. http://www.iegtoclub.com/Tech%20Lib/gto_axle_identification.htm Also you want to put some of the GM or Ford limited slip additive in even if the gear lube claims it has the additive in it from my experience. Makes for a less noisy rear at low speeds.
Lol learn to differentiate your differentials. I like it. ðŸ˜ÂÂ
Nice video Eric .
Hey look for a Nova Drag car in. The Uk Called " Nosferatu"
One cool looking Nova .
Nice to see you again, hadn't been here since the Fairmont saga killed your channel for me.
I'm trying to put together a parts list foe a 5 lug conversion on a cb7.
Bought Timken axle bearings for my Son's Ford 7.5 inch differential and guess what came in the box!!
Koyo bearings in a Timken box. "Life is like a box of chocolates; you never know what you're going to get!" Forest Gump