Posted By: Clayton
8 3/4 questions - 02/05/12 04:28 PM
Gonna be putting a 8 3/4 in my 67 barracuda and don't know much about them. I have a 489 case but Ive been told I can put any carrier in any case so my question is which is best for mostly street 500 hp big block, the one with clutches or the cone type. Ive heard conflicting advice about both so I would appreciate any help. Thanks, Clay
Posted By: StukaJU87
Re: 8 3/4 questions - 02/05/12 06:28 PM
Use the clutch type. I have the cone type and it only hooks one wheel sometimes, sometimes both. It's a crapshoot.
Posted By: Clayton
Re: 8 3/4 questions - 02/05/12 07:13 PM
So I can just get any clutch type carrier from 741,742,489 case, add the gears I want and I'll be fine? Sorry if these seem like dumb questions but at this point I've been told so many things that I'm not sure what is right and I figured this would be the best place to ask;)
Posted By: Kern Dog
Re: 8 3/4 questions - 02/05/12 07:14 PM
The title read 8 3/4 questions.
I only read one question. Feel free to add in the other 7 3/4 questions. We are always willing to help.
Posted By: Kern Dog
Re: 8 3/4 questions - 02/05/12 07:17 PM
The 3/4 race cam is for HALF assed Chevy guys!
Posted By: Clayton
Re: 8 3/4 questions - 02/05/12 07:28 PM
I might have to stop at 8 5/8 questions before I learn just enough to be dangerous...:)
Posted By: Pacnorthcuda
Re: 8 3/4 questions - 02/05/12 07:29 PM
What size socket is required to adjust torsion bar ride height?
Posted By: Junky
Re: 8 3/4 questions - 02/05/12 08:41 PM
I must be one of the lucky ones. Purchased a 3.73 cone type pig from Randy's 10 years ago. Still works perfect.
Posted By: Clayton
Re: 8 3/4 questions - 02/05/12 09:26 PM
Yea popular opinion seems to be the clutch type especially since its rebuildable. Now have to pull the center and see whats in it, since its been back braced and has aftermarket axels I have the sneeking suspicion thats its spooled......
Posted By: SportF
Re: 8 3/4 questions - 02/05/12 09:46 PM
I wasn't going to reply to this as this topic comes up all the time. Why will the spyder gears gall. There isn't much load on them when the unit is wore and there is no load going straight ahead. On the cone vs clutch, those clutch types (used) are pretty rare. The cone types can be rebuilt as well. If only one wheel grabs the unit is wore. I rebuilt a wore out cone unit 15 years ago, and crudely at that. In a '62 Plymouth running low 12's with well over 400 passes and 10k in hard street miles it still works. This is with tapered axles and a ball and trunnion joint at the tranny, and that isn't suppose to work either. I took a cone type gear set out of a junkyard truck with 200,000+ miles on it and the cone stuff was still good. Give me the cone stuff every time. This isn't stuff I think, its stuff I know. Good luck.
Posted By: John_Kunkel
Re: 8 3/4 questions - 02/05/12 09:55 PM
The cone-type spider gears are more likely to gall because there's only two of them, the clutch-type has four.
Since it's unlikely that any two tires are the exact same diameter, the differential gears will be under load even when going straight ahead.
Posted By: DoctorDiff
Re: 8 3/4 questions - 02/05/12 10:02 PM
You run into problems when the cones wear and the unit turns into an open differential.
If you do many 1 wheel burn-outs with a worn cone sure-grip, the spider gears friction weld themselves to the differental cross shaft. This causes the cross shaft to spin, which eventually wallows out the pin bore in the carrier.
Posted By: SportF
Re: 8 3/4 questions - 02/05/12 10:17 PM
Doesn't that also means open rears must be subject to the same galling effect, if not more, and you really don't hear much of that, unless you run low on oil.
Posted By: DoctorDiff
Re: 8 3/4 questions - 02/05/12 10:43 PM
Open differentials suffer the same fate. I see it all the time.
If you perform extended burn outs with an open differential, you will friction weld the spider gears.
Because spider gears do not contain bearings, they are designed to spin SLOWLY only when the vehicle goes around corners, NOT thousands of RPMs during a 1 wheel burn-out.
Of course, this can also happen with an over-zealous driver stuck in mud/snow/ice.
Posted By: StukaJU87
Re: 8 3/4 questions - 02/05/12 10:50 PM
So, I guess I will soon be needing a new Eaton TrueTrac somewhere down the line.
Seriously though....if I drive the worn out cone type without doing extensive burnouts, will it live or self destruct?
Posted By: buildanother
Re: 8 3/4 questions - 02/05/12 11:03 PM
It should last for normal cruising. I don't like the big lash in spider-side gears that is caused by the cone and case wear. The springs still push the side gears out but that causes the 4 gears to ride higher up on teeth where they become a little weaker for the driver that still intends to put slicks on it and race it. That enhances it's need to explode I believe.
