Sure grip questions

[General Ryan]

I have the 3:55 axle package tag on my car, but that doesn't mean that along the way something was changed or a sure grip. I'm pretty darn sure I have 3:23's in there now.

What I'm really getting at here is how can I tell if I have no sure grip or its just not worn out without taking the pig out of the 8 3/4?

If I do a brake stand, it peg legs, in reverse, if I jab it and sqeel em, it'll leave 2 marks. Turning left and stabbing it will send it sideways, turn right and it'll one leg unless its wet (sometimes).
Going straight in wet will sail the rear out and very rarely I can get both to go for a burnout, like today.

I'm just not convined its an open rear and not a badly worn and sloppy suregrip. Next question, can I rebuild one or do I have to replace the whole thing like I'm adding a sure grip??

[derailed]

Im no expert at this but i believe even if the clutches were worn i would think both rear wheels would still spin in the same direction with the rear wheels jacked up off the ground if it were a sure grip. Have you tried that test yet? If they spin opposite each other its an open rear. They have rebuild kits like this one for the clutch style units.

http://cgi.ebay.com/ebaymotors/Dodge-Chrysler-Plymouth-8-3-4-Sure-Grip-Rebuild-Kit_W0QQitemZ8009807279QQcategoryZ33731QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

[Duey]

Ryan, lift one of the rear wheels off the ground by jacking under the axel spring pad...if the raised wheel turns easily, you have an open differetntial.   If it's very difficult or impossible to turn, you have a good SG.   If it has some resistance but will still turn with moderate force applied, you may have a cooked SG unit (489 case w/ cones needs complete rebuild, 742 with clutches can be refreshed).

Cheers,
Duey

[General Ryan]

I have a 489 case.
I'll dbl check when I lift er up

[Ghoste]

And quit doing brake stands in reverse!  You're going to really break something (no pun intended).

[General Ryan]

And quit doing brake stands in reverse!   You're going to really break something (no pun intended).

HAHA, no, I don't do them, I only stated that because sometimes when backing in the driveway, if I give er too much throttle to go up the slope, it'll leave a couple small patches.

Wouldn't sit there and smoke em in reverse, thats ridiculous!!!

[Ghoste]

It is, but you'd be amazed how many do it.  Admittedly more popular in the brand X camp, but still.

[aifilaw]

Im no expert at this but i believe even if the clutches were worn i would think both rear wheels would still spin in the same direction with the rear wheels jacked up off the ground if it were a sure grip. Have you tried that test yet? If they spin opposite each other its an open rear. They have rebuild kits like this one for the clutch style units.

http://cgi.ebay.com/ebaymotors/Dodge-Chrysler-Plymouth-8-3-4-Sure-Grip-Rebuild-Kit_W0QQitemZ8009807279QQcategoryZ33731QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

This is actually true, the worm sure grip units will act like a sure grip off the gruond, but when your on the ground and putting power they won't function, the test off the ground to see if its a suregrip works is fine....

Another thing of note here is that even with a worn sure-grip, or an open differential, if you have enough torque at the flywheel you can actually make an open differential mimick a sure grip unit through sheer power output, I find this comes into play upwards of 450 ft lbs of torque from the flywheel

[myk]

It is, but you'd be amazed how many do it.   Admittedly more popular in the brand X camp, but still.

They've been watching Bullitt again, haven't they?