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Old 03-03-2013, 01:38 PM   #1
Yellow72C10
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14 bolt differential?

i need some help with my diff under my truck, a 72 k10 short stepper. i doubt its been cracked opened since it rolled off the line, so should i replac the entire thing or just a fluid swap? im a newbie so any help is appreciated. thanks!!
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Old 03-03-2013, 01:49 PM   #2
mr48chev
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Re: 14 bolt differential?

If it isn't broke why fix it outside of normal maintenance? Changing the gear oil in the rear axle is under the Normal maintenance thing.

My info shows a 14 bolt as 73 and up though. As it is a K rather than a C two wheel drive has a previous owner changed the axles over to the later axles which is a very popular swap on Chevy 4x4 trucks?

Changing a Half ton truck to the 14 bolt 8 lug 3/4 ton axles is another popular swap swap around here to get a full floating rear axle and heavier duty running gear for serious four wheeling.
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Old 03-03-2013, 05:32 PM   #3
Yellow72C10
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Re: 14 bolt differential?

I doubt my grandad would've changed axles, cause it was just a farm truck...but it is definitely a 14 bolt. How do you change fluid?
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Old 03-03-2013, 08:37 PM   #4
Yellow72C10
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Re: 14 bolt differential?

Well okay you are right sir. It's a 12 bolt, not a 14 bolt...my bad. What gear oil would you recommend, maybe 90 wt? Thanks!!
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Old 03-05-2013, 02:10 PM   #5
MJN
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Re: 14 bolt differential?

Just unbolt the differential cover and let the oil drain out, try to keep as much dirt and rust from falling in when you do this. Use 80w90 GL-5 gear oil. If it is a posi differential get a bottle of friction modifier from your GM dealer and add that when you refill to keep the clutches working properly. The fill plug is on the front side of the housing, just fill it until oil begins to run back out of the fill hole.
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Old 03-05-2013, 05:57 PM   #6
truckster
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Re: 14 bolt differential?

Now is a good time to check your seals, at the wheels and the pinion. Also check the condition of the wheel bearings. With the brake drums off, rotate the axle. Listen and feel for any grinding or unusual noises. Check the ring gear for any chipped or broken teeth. Also make note of any pieces of metal that are in the bottom of the pumpkin.

80W90 is good, I also like the synthetic stuff at Walmart.
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Old 03-05-2013, 07:20 PM   #7
SS Tim
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Re: 14 bolt differential?

If you don't them download a service manual and an overhaul manual.
http://ventura.craigslist.org/sys/3652590086.html
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