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Author Topic: rearend gears  (Read 3394 times)

Offline 75??? franken-trunk

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rearend gears
« on: November 02, 2007, 03:47:53 am »
i have a 84ish gmc sierra classic short box. it a k15 that has a 305, 700r4, np208, 10 bolt front and back non splicer, corporate, dana ect... any one have a idea on the gears i have they feel steep like 3.08"s but i know that they may not be... and no there is no sticker in the glove box... any ideas thanks
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Offline VileZambonie

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Re: rearend gears
« Reply #1 on: November 02, 2007, 04:59:28 am »
Only sure way to tell is to pop the meatball cover off. If you have 41 teeth on the ring gear and 11 on the pinion... 41 ÷ 11= 3.73 etc
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Offline Blazin

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Re: rearend gears
« Reply #2 on: November 02, 2007, 07:08:03 am »
Not quite sure what you mean by this?
" 10 bolt front and back non spicer, corporate, dana ect... "
If they are 10 bolts they should be corprate. Or AAMC Which is the company that makes what are referred to as corprate axles in all makes of light duty trucks. My 84 K10 4x4, 305, SM456, NP 208, had 10 bolts with 2:73 gears in it. The only 4x4 I have ever seen with that high of gear. I swapped in a 12 bolt from and older 2x truck as I blew the original rearend burning tire. most common gears I have seen in the early to mid 80s trucks is 3:42. But have seen a few with 3;08, and 3:73s.
« Last Edit: December 17, 2007, 07:42:48 pm by Blazin »
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Offline sav_x69

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Re: rearend gears
« Reply #3 on: December 17, 2007, 06:33:34 pm »
are 3.42 any good wit a sm465
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Offline Blazin

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Re: rearend gears
« Reply #4 on: December 17, 2007, 07:45:06 pm »
My 86 K 2500 has 3:42s and I like them. It plows good, but is not so low geared it can cruise at 75 80 on the highway and not be twisting the motor out from under the hood.
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Offline loudnlow87

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Re: rearend gears
« Reply #5 on: December 17, 2007, 11:37:37 pm »
pinion and ring gear tooth count is stamped on the ring gear. so just look for 2 consecutive numbers like "41 12" and divide them
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