MikeP84

Has anyone else heard grinding from either their 4+3 or rear end while turning very hard??? I only get the grinding noise under very hard turning. Fluids are good on both. Loud while in the car but you cant hear it very well from the outside of the car. I cant see anything (half shafts/drive shaft) rubbing anywhere. Sounds like pennies in a blender. Thanks!

BlueTwoToneCorvette

Sounds like your diff friction plates are slipping like they should during low speed tight turns. You say your diff fluid level is good, as in up to the check hole?

Is your diff working otherwise?

The sound shouldn't be very loud, at least it's not noticeable in my 85. But my exhaust is loud.

I would pump all the diff fluid out from the side hole using one of those $10 fluid pumps and make sure there are no metal fragments in it. Then replace with gear oil plus the limited slip additive. I think people with more experience than me with diffs have posted that the diff is sensitive to type of gear oil and LSD additives you put in.

MikeP84

Yeah I was kinda thinking it was my diff slipping one gear over another but it seems to be louder near the trans but it's hard to tell. I can hear it over my car only exhaust.

Yeah diff works fine other wise. Im pretty sure I replaced the fluid last year and got the additive from chevy but for >100 its alot cheaper than a new dana so I might as well do it again.

The only other think I can think it might be is my trans flexing from the torque and it's trying to go into two gears at once if that makes sense.

383vett

The differential doesn't "slip one gear over the other". The gears should always mesh, the clutch pleates might be chattering. Before draining the fluid, try adding a 1/2 bottle of limited slip additive to see if it makes a difference. The tranny isn't going to know if you are turning or not.

MikeP84

Thank you for the reply and yes I would agree it isn't actually slipping one gear over the teeth of another gear, it is a limited slip after all and they are supposed to spin independently of each other. I can try to put some extra slip additive in it and see. I have the limited slip additive you can get from chevy btw. Expensive but worth it in my opinion.

I have hear that they flex but it would only make sense if it is flex under acceleration only and not turning.

The only reason why I thought it might be the trans is bc it sounds like one gear spinning at speed and hitting another gear. As if it is in second and it is trying to mesh into third gear while in second.