what kind of rear end do i have?

[prostreetC-10]

Originally Posted by J Knight

I think this whole thread was informatively entertaining!

.....and I think you NAILED why I like these guys so much!

[patmchicago]

Forty-six years old and going to do this on the "new" 79 Big Ten that I just bought. First time I've ever done one -only 30 years behind you
project 7 - and probably the first time ever done on the 150,000 mile truck. It's a 12 bolt on a 350 automatic.

Thanks for all the great information so far, but I have one more question. What is the best way to remove the old gasket.

[patmchicago]

Not sure if anyone was going to chime in but don't need the info. as I got er done today.

[pcdoc2001]

I rebuild differentials every day. Never depend on the tags to see what you have. Elevate the rear tires. With your truck in neutral look at the valve stem on one tire and line it up with something.(I just put mine at 12:00). Count how many turns it takes to spin the driveshaft around until the wheel rotates once. If you spin the driveshaft just barely over 3 times you have a 3.07

[b454rat]

How bout take the cover off and read the numbers? Also this post is 6 years old.

[pcdoc2001]

Lol, I didn't see that the post was six years old but the advice that I gave is still good advice. Many people want to make gearing changes and need to know what they have. You don't have to pull the cover to figure out the current ratio. If I spin the driveshaft barely over 3 turns it's a 3.07 barely shy of 3 1/2 turns and it's a 3.42, almost exactly 3 3/4 and it's a 3.73 just over 4 turns it's a 4.10. If both wheels are spinning it's not an open carrier. The original poster was sixteen years old so now he's 21 and again many people want to know what they have without disassembly. Also I never use a gasket on the rear end. I check the cover with a straight edge and use grey sealant.

[Ironangel]

Originally Posted by pcdoc2001

Lol, I didn't see that the post was six years old but the advice that I gave is still good advice. Many people want to make gearing changes and need to know what they have. You don't have to pull the cover to figure out the current ratio. If I spin the driveshaft barely over 3 turns it's a 3.07 barely shy of 3 1/2 turns and it's a 3.42, almost exactly 3 3/4 and it's a 3.73 just over 4 turns it's a 4.10. If both wheels are spinning it's not an open carrier. The original poster was sixteen years old so now he's 21 and again many people want to know what they have without disassembly. Also I never use a gasket on the rear end. I check the cover with a straight edge and use grey sealant.

Actually, when you elevate both wheels off the ground, both wheels should spin, however; If they spin in the same direction, you have a LS (Posi) If they spin in opposite directions, you have an open carrier. If only one wheel turns, you have a problem! It's always best to pop that cover and get the tooth count off the edge of the ring gear. You can inspect wear, find out for sure what kind of locker or LS you have if any at all or if it's an open carrier. There's really no good reason not to use a diff cover gasket. If I wrap up $1000 on rear end build and find out some silicon found it's way into a bearing cage because somebody went crazy making an $8 gasket? Aint worth the risk in my not so humble opinion..."Just sayin" ~Ghostrider~ PS.