maybe a dumb question

[Roger63]

Here we go I have a 8.75 489 case diff in my charger. I done the spin the whell trick they go opposite direction. Is it possible that a suregrip will mimic a open carrier if it is in need of rebuilding.

 

[benno440]

yes I believe so, I have a 489 centre and I put an eaton true trac in mine and they spin opposite ways until torque is applied then the helical gears contact each other and spins both wheels.
but I believe your correct with your question, either that os it has been removed completely

 

[Roger63]

When I apply torque I get one wheel spin so maybe worn out?

 

[Hemi Rebel]

If a limited slip differential is worn out it becomes an open differential. Sounds like you either have that, or it is not a limited slip differential to begin with

 

[Cranky]

Yup....very possible and depending on if it's a cone unit or a clutch will depend on how much damage is there. If it is a worn out SG and you continue to burn down one tire, things only get worse so if you suspect it might be a SG, pull it and check it out. What year car do you have and do you know if the diff has ever been changed out? With a clutch type, you can pull one axle and using a good flashlight, you will see a button in the center of the splines but if it's a cone type, you will see a large 'button' that's around 1" or so in diameter. Problem with the cone unit is that the center pin is about the same size as on open diff....

 

[Roger63]

It is a 71 rt charger and is original to the car but makes no noise or whining or clunking noises

 

[Hemi Rebel]

You have owned the car since new? Probably just a worm out unit. It wont make noise. Just will not work as designed