Help Identifying Differential - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**MDPotter** · 08-30-2019, 10:48 AM

I'm curious to know more about my rear axle. My 68 GMC C15 has a Dana/Spicer 44, but I don't know anything about the differential. The truck was a factory 307/4-speed. It does have a factory metal tag attached to one of the cover bolts that indicates to use limited slip fluid. The stamping reads: 3 25 68 DANA 18437 A3D80 46-13

Is this really a limited slip? And does the 46-13 mean it's got 3.53 gears?

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Name: IMG_5896[1].jpg
Views: 354
Size: 61.5 KB

Bigdav160 · 08-30-2019, 11:08 AM

Best differential case made, dana powerlock

geezer#99 · 08-30-2019, 11:21 AM

Yup, it’s more commonly called a 3.54 ratio.

**MDPotter** · 08-30-2019, 01:31 PM

Awesome, thanks guys. So it's a good rearend to handle my 400 HP LS?

I've done some research on how to replace bearings and seals, but not sure if they need it or not. The truck has 35,000 miles on it and it seems to be a little difficult so if I don't need to replace them I don't want to. I'll know better what condition they're in when I rebuild the brakes.

GASoline71 · 08-30-2019, 01:45 PM

You will snap an axle before you'll break that carrier. D44's can handle a bit, but not the most stout axle out there.

Gary

BigBird05 · 08-30-2019, 02:40 PM

Those seals are 50 years old. Why are you even asking?

08-30-2019, 10:48 AM	#1
MDPotter Senior Member Join Date: Aug 2018 Location: Western Colorado Posts: 1,165	Help Identifying Differential I'm curious to know more about my rear axle. My 68 GMC C15 has a Dana/Spicer 44, but I don't know anything about the differential. The truck was a factory 307/4-speed. It does have a factory metal tag attached to one of the cover bolts that indicates to use limited slip fluid. The stamping reads: 3 25 68 DANA 18437 A3D80 46-13 Is this really a limited slip? And does the 46-13 mean it's got 3.53 gears? __________________ 1964 Chevy C10 - Gen IV 5.3 Restomod http://67-72chevytrucks.com/vboard/s...d.php?t=768632 1968 GMC C15 - Gen III 6.0 Restomod http://67-72chevytrucks.com/vboard/s...d.php?t=772047 1969 Chevy C10 - Restoration http://67-72chevytrucks.com/vboard/s...d.php?t=809184 1978 Chevy Scottsdale K20 1993 Chevy C1500 - 5.3/T56 swapped 2008 Silverado Duramax

08-30-2019, 11:08 AM	#2
Bigdav160 Registered User Join Date: Apr 2011 Location: Klein Texas Posts: 3,852	Re: Help Identifying Differential Best differential case made, dana powerlock __________________ My Classics: '72 K20 Suburban + '65 Dodge Town Wagon '72 Corvette Roadster +'67 Corvette Roadster '73 Z-28 Camaro '63 Ford SWB Uni Pickup '50 Ford Coupe

08-30-2019, 11:21 AM	#3
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,731	Re: Help Identifying Differential Yup, it’s more commonly called a 3.54 ratio.

08-30-2019, 01:31 PM	#4
MDPotter Senior Member Join Date: Aug 2018 Location: Western Colorado Posts: 1,165	Re: Help Identifying Differential Awesome, thanks guys. So it's a good rearend to handle my 400 HP LS? I've done some research on how to replace bearings and seals, but not sure if they need it or not. The truck has 35,000 miles on it and it seems to be a little difficult so if I don't need to replace them I don't want to. I'll know better what condition they're in when I rebuild the brakes. __________________ 1964 Chevy C10 - Gen IV 5.3 Restomod http://67-72chevytrucks.com/vboard/s...d.php?t=768632 1968 GMC C15 - Gen III 6.0 Restomod http://67-72chevytrucks.com/vboard/s...d.php?t=772047 1969 Chevy C10 - Restoration http://67-72chevytrucks.com/vboard/s...d.php?t=809184 1978 Chevy Scottsdale K20 1993 Chevy C1500 - 5.3/T56 swapped 2008 Silverado Duramax

08-30-2019, 02:40 PM	#6
BigBird05 Registered User Join Date: Aug 2019 Location: Cheraw Posts: 1,300	Re: Help Identifying Differential Those seals are 50 years old. Why are you even asking?



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