Will lack of friction modifier cause all sorts of funny noises? (chattering, rubbing, etc)

Do all factory posi's need modifier? (in particular, a 92)

Will putting modifier in a rear that doesnt need it cause any problems?

Long story short, I just had my entire rear changed and its making a hell of a racket at slow turns.

 

More details?

Did you get it from a junk yard?
Did you have it rebuilt?
Does it have posi, locker, spool?

 

yes, a lack of friction modifier can cause noise. it will get hot and not slip when required to (i.e. slow turns). if it needs it, add it. as for that year needing it, im not sure. i added some to the rear of my 95 blazer when i changed the oil, then i found out it wasnt required. oh well, its in it now. i havent had any issues for 3k miles

 

4th gen's need it, is the unit different in the 3rd gens? The additive keeps the clutches from getting gummy and sticking, which just plain oil will do. You will hear and feel a clunk-clunk-clunk as you go through a slow turn. Using the additive if it isn't needed (non-clutch l.s.) won't hurt a thing.

 

It was a junkyard rear end. Brought the entire rear to a shop and had the guy install the gears. Hes a reputable shop (and actually have their own NASCAR car they race)....Its all set up correctly. Im just wondering if he maybe forgot (or didnt realize) to put a modifier in. Its a factory posi from a 92. The installer checked it all out, said all the internal springs etc were in spec....

I installed everything last week and its making a hell of a chatter at slow turns. I cant figure out where the hell else it may be coming from as Ive triple checked that everything is tight, nothing appears broken, and straight line driving has no issues at all.

 

Its not a clunk clunk clunk.....its a metallic 'ir-ir-ir-ir-ir' with a vibration. Its driving me nuts as I cant even begin to find the cause.

 

sounds like you should try adding friction modifier.

Is it your first posi? Could it be noise from the tires chattering?
If I couldn't tell on my own I would ask the shop who put it in to listen to it.

Oh, I didnt see your second post. I wouldnt drive it much like that.

 

I would still put in the additive, take the car to an open parking lot, and do a lot of easy figure-8's (that'll work the stuff in faster) and see if that clears it up.
Maybe the reaction on yours is different from what I've experienced in my old Vettes.

 

Im taking the car back to the shop on Monday (weather providing). He installed the gears, I installed the axle assembly. I guess there is some chance that I screwed something up, but Ive checked it all over. Its just turning into a royal pain in the ***. The guy did the job for me because he thought it was gonna be a quick simple swap....I know hes already lost money on the job. I just hate having other people work on my car, in the middle of the summer, for a problem in which I cant diagnose......

 

So, are you going to stick the lube in your rearend and rotate it, or not?
That didn't sound quite right, did it?