Rear Diff clicking noise after Fluid change........

I've done plenty to my 2nd gen, but last week I helped a buddy change out Front & Rear diff fluids for maintenance. Pretty simple task but now his rear diff is making a clicking sound when turning. I went over and he pulled in & out of driveway a couple times and its pretty noticeable.

Is Valvoline 75/90 not a good choice? Does it need a friction modifier added? Any input would be great.

I did remove fill plug and oil starts to drip out so I know its full. I'm just scratching my head

Thank you

 

What year? Locker?

 

here is the info i have....

96 truck with a 3.4 swap, auto trans, 4x4, lifted lifted and body lift.

1. truck doesn't have accuator on diff like my 2nd gen does.
2. when i jack up left rear tire (right rear still on ground) with truck in park, tire spins forward and makes clicking sound, driveshaft no move. Try to spin tire backwards it stops, locks up.
3. Jack whole rear up, (both tires off ground) you can spin one side and hold the other side still, makes clicking noise and driveshaft spins when in neutral.

just drives fine straight (no noise) but turning it clicks pretty loud when walking next to rear tires...

I'm pretty mechanically inclined but im scratching my head on this one and don't want to pull the diff if i don't have to...maybe trying different oil with friction modifier first??

 

I’ll have to re-read that, but my question remains unanswered: locker, or no locker?

I did read that there is no actuator.

Is the diff stock?

 

Did you just drain and refill? No pulling axles, brakes etc?

 

just a plain drain and refill...

i thought it might have locker until i jacked up one tire and it spins with the other on the ground....thought lockers were "lockers" thats why the tires usually chirp when turning...

 

Also you mention friction modifier. Does that mean you know it has a limited slip (and obviously no locker)

 

If it’s a spool yes. If it’s a selective locker like the factory one or an arb etc, you can turn it off.

 

its a new well used truck to my buddy, he knows not much about them, hence why he asked me to help with fluid changes....

def not a arb (no air hose), def not a spool, and no accuator motor on diff housing...so I'm thinking its just a plain jane rear end from the 96'......

 

I think you should find out exactly what kind of carrier is in it. It might just be friction modifier that is needed, but some diffs can be damaged by that stuff too.

 

Run the vin.

 

How’d the oil look that came out?

 

i can try and get phone video this sunday,

not aweful, but like a dark coffee color with a lil creamer....no metal on drain plug

just wondering since it didn't start making the noise til recently, maybe trying a diff oil/additive first and report back?

thank you for the input @Rujack and trying to point me in the right direction

This truck has been backyard built from what I see....we are in Hawaii and you may know how some things go down...

 

Yea, I think more info is needed. Maybe someone more helpful than me will have some input in the mean time.